Assignment 17: Flutter REST API Program
Objective
Create employee data (empid, empname, salary, dept) and display it in a ListView using REST API.
PART 1: Project Setup
Step 1: Add HTTP Dependency`
Change View in Android Studio
- In Android Studio, change view from Android to Project
- This allows you to see all project files
Modify pubspec.yaml
- Open
pubspec.yaml file
- Locate the
dependencies: section
- Add the following dependency:
dependencies:
flutter:
sdk: flutter
http: ^1.1.0
- Save the file
- Run command in terminal:
flutter pub get
Description: The http package enables making HTTP requests to REST APIs
PART 2: Creating Mock API
Step 2: Generate JSON Data
Create Employee JSON Array
[
{
"empid": 101,
"empname": "John Doe",
"salary": 50000,
"dept": "IT"
},
{
"empid": 102,
"empname": "Jane Smith",
"salary": 60000,
"dept": "HR"
},
{
"empid": 103,
"empname": "Mike Johnson",
"salary": 55000,
"dept": "Finance"
},
{
"empid": 104,
"empname": "Sarah Williams",
"salary": 65000,
"dept": "IT"
}
]
Description: JSON array containing employee records with 4 fields
Step 3: Create Free API Endpoint on Mock.io
Process:
- Go to https://mocki.io/
- Click "Create Mock API"
- Paste your JSON data
- Click "Generate Mock Endpoint"
- Copy the generated URL (e.g.,
https://mocki.io/v1/1eabf0c9-fff1-4656-af13-9c957251aa7f)
- Save this URL for use in your app
Description: Mock.io provides free hosted JSON endpoints for testing
Step 4: Generate Model Class
Use QuickType.io
- Go to https://app.quicktype.io/
- Paste your JSON data in left panel
- Select Dart as output language
- Copy the generated Dart model class
- Use this as template for
Employee.dart
Description: QuickType automatically generates type-safe model classes from JSON
PART 3: Creating the Flutter Application
Step 5: Create Employee Model (Employee.dart)
Create file: lib/Employee.dart
import 'dart:convert';
// Function to parse JSON array string into List of Employee objects
List<Employee> employeeFromJson(String str) =>
List<Employee>.from(json.decode(str).map((x) => Employee.fromJson(x)));
// Function to convert List of Employee objects to JSON string
String employeeToJson(List<Employee> data) =>
json.encode(List<dynamic>.from(data.map((x) => x.toJson())));
class Employee {
int empid;
String empname;
int salary;
String dept;
// Constructor with required parameters
Employee({
required this.empid,
required this.empname,
required this.salary,
required this.dept,
});
// Factory constructor to create Employee from JSON map
factory Employee.fromJson(Map<String, dynamic> json) => Employee(
empid: json["empid"],
empname: json["empname"],
salary: json["salary"],
dept: json["dept"],
);
// Method to convert Employee object to JSON map
Map<String, dynamic> toJson() => {
"empid": empid,
"empname": empname,
"salary": salary,
"dept": dept,
};
}
Key Components:
- employeeFromJson(): Converts JSON string to List of Employee objects
- employeeToJson(): Converts List of Employee objects to JSON string
- fromJson(): Factory constructor for creating Employee from JSON map
- toJson(): Converts Employee object to JSON map
Step 6: Create Remote Service (Remote_Services.dart)
Create file: lib/Remote_Services.dart
import 'package:http/http.dart' as http;
import 'Employee.dart';
class RemoteService {
// Async function to fetch employees from API
Future<List<Employee>?> getEmployees() async {
var client = http.Client();
// Parse the API endpoint URL
var uri = Uri.parse("https://mocki.io/v1/1eabf0c9-fff1-4656-af13-9c957251aa7f");
// Make GET request to the API
var response = await client.get(uri);
// Check if request was successful (status code 200)
if (response.statusCode == 200) {
var json = response.body;
return employeeFromJson(json);
}
// Return null if request failed
return null;
}
}
Key Components:
- http.Client(): Creates HTTP client for making requests
- Uri.parse(): Parses string URL into Uri object
- client.get(): Makes GET request to API
- response.statusCode: HTTP status code (200 = success)
- response.body: Response data as string
- employeeFromJson(): Converts JSON response to List of Employee objects
Step 7: Create Main Application (main.dart)
Create/modify file: lib/main.dart
import 'package:flutter/material.dart';
import 'Remote_Services.dart';
import 'Employee.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
),
home: const MyHomePage(title: 'Flutter REST API'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<Employee> employees = [];
var isLoaded = false;
@override
void initState() {
super.initState();
getData();
}
getData() async {
try {
final result = await RemoteService().getEmployees();
if (result != null) {
setState(() {
employees = result;
isLoaded = true;
});
}
} catch (e) {
print("Error Fetching Employees: $e");
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: Text(widget.title),
),
body: Visibility(
visible: isLoaded,
replacement: const Center(child: CircularProgressIndicator()),
child: ListView.builder(
itemCount: employees.length,
itemBuilder: (context, index) {
return Card(
margin: const EdgeInsets.all(8.0),
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text('EMPID: ${employees[index].empid}'),
Text('Name: ${employees[index].empname}'),
Text('Salary: ${employees[index].salary}'),
Text('Dept: ${employees[index].dept}'),
],
),
),
);
},
),
),
);
}
}
Key Components Explained:
State Variables
- employees: List to store fetched employee data
- isLoaded: Boolean flag to track loading state
initState()
- Called when widget is first created
- Calls
getData() to fetch employees immediately
getData()
- async: Function runs asynchronously
- try-catch: Error handling for API failures
- await: Waits for API response
- setState(): Updates UI with fetched data
UI Components
- Scaffold: Basic app structure
- AppBar: Top bar with title
- Visibility: Shows loading or data based on
isLoaded
- CircularProgressIndicator: Loading spinner
- ListView.builder: Efficiently builds list items
- Card: Material design card for each employee
- Column: Vertical layout for employee details
PART 4: Running the Application
Step 8: Run the App
Using Android Studio:
- Connect Android device or start emulator
- Click the green "Run" button
- Select target device
- Wait for app to build and launch
Using Command Line:
flutter run
Using Chrome (Web):
flutter run -d chrome
Description: Builds and launches the Flutter application
PART 5: Understanding the Data Flow
Complete Data Flow Diagram
1. App Starts
↓
2. initState() called
↓
3. getData() executed
↓
4. RemoteService.getEmployees() called
↓
5. HTTP GET request to Mock.io API
↓
6. API returns JSON response
↓
7. employeeFromJson() parses JSON
↓
8. List<Employee> created
↓
9. setState() updates UI
↓
10. ListView.builder displays employee cards
Assignment 16: Flutter Database Program (SQFlite)
Objective
Create 2 fields (name, age) and perform CRUD operations: create, insert 5 rows, delete record (by id), update record (by id), and show all records.
Step 1: Add Dependencies
Change view in Android Studio from Android to Project
Open pubspec.yaml and add:
dependencies:
flutter:
sdk: flutter
sqflite: ^2.3.0
path_provider: ^2.1.1
Save and run:
flutter pub get
Step 2: Create Database Helper (database_helper.dart)
Create file: lib/database_helper.dart
import 'dart:io';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';
import 'package:path/path.dart';
class DatabaseHelper {
static final _dbName = 'student.db';
static final _dbVersion = 1;
static final _tableName = 'student';
static final columnId = '_id';
static final columnName = 'name';
static final columnAge = 'age';
// Singleton pattern
DatabaseHelper._privateConstructor();
static final DatabaseHelper instance = DatabaseHelper._privateConstructor();
static Database? _database;
Future<Database?> get database async {
_database ??= await _initiateDatabase();
return _database;
}
_initiateDatabase() async {
Directory dir = await getApplicationDocumentsDirectory();
String path = join(dir.path, _dbName);
return await openDatabase(path, version: _dbVersion, onCreate: _onCreate);
}
Future _onCreate(Database db, int version) async {
db.execute(
"CREATE TABLE $_tableName($columnId INTEGER PRIMARY KEY, $columnName TEXT NOT NULL, $columnAge INTEGER NOT NULL)"
);
}
// INSERT
Future<int> insert(Map<String, dynamic> row) async {
Database? db = await instance.database;
return await db!.insert(_tableName, row);
}
// SELECT ALL
Future<List<Map<String, dynamic>>> showAll() async {
Database? db = await instance.database;
return await db!.query(_tableName);
}
// UPDATE
Future<int> update(Map<String, dynamic> row) async {
Database? db = await instance.database;
int id = row[columnId];
return await db!.update(_tableName, row, where: '$columnId=?', whereArgs: [id]);
}
// DELETE
Future<int> delete(int id) async {
Database? db = await instance.database;
return await db!.delete(_tableName, where: '$columnId=?', whereArgs: [id]);
}
}
Step 3: Create Main Application (main.dart)
Create/modify file: lib/main.dart
import 'package:flutter/material.dart';
import 'database_helper.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Database Program',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
),
home: const MyHomePage(title: 'SQFlite Program'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final TextEditingController _name = TextEditingController();
final TextEditingController _age = TextEditingController();
final TextEditingController _id = TextEditingController();
List<Map<String, dynamic>> _records = [];
@override
void initState() {
super.initState();
// Uncomment if you want auto-fetch on start
// _fetchRecords();
}
void _clearInputs() {
_name.clear();
_age.clear();
}
// ADD RECORD
Future<void> _addRecord() async {
String name = _name.text.trim();
int? age = int.tryParse(_age.text.trim());
if (name.isEmpty || age == null) return;
int insertedId = await DatabaseHelper.instance.insert({
DatabaseHelper.columnName: name,
DatabaseHelper.columnAge: age,
});
print("Inserted ID: $insertedId");
_clearInputs();
_fetchRecords(); // Uncomment if you don't want auto-refresh
}
// UPDATE RECORD
Future<void> _updateRecord() async {
int? id = int.tryParse(_id.text.trim());
String name = _name.text.trim();
int? age = int.tryParse(_age.text.trim());
if (id == null || name.isEmpty || age == null) return;
int updated = await DatabaseHelper.instance.update({
DatabaseHelper.columnId: id,
DatabaseHelper.columnName: name,
DatabaseHelper.columnAge: age,
});
print("Updated $updated row(s)");
_clearInputs();
_fetchRecords(); // Uncomment if you don't want auto-refresh
}
// DELETE RECORD
Future<void> _deleteRecord() async {
int? id = int.tryParse(_id.text.trim());
if (id == null) return;
int deleted = await DatabaseHelper.instance.delete(id);
print("Deleted $deleted row(s)");
_clearInputs();
_fetchRecords(); // Uncomment if you don't want auto-refresh
}
// FETCH ALL RECORDS
Future<void> _fetchRecords() async {
List<Map<String, dynamic>> rows = await DatabaseHelper.instance.showAll();
setState(() {
_records = rows;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: Text(widget.title),
),
body: Padding(
padding: const EdgeInsets.all(12.0),
child: ListView(
children: [
TextField(
controller: _name,
decoration: const InputDecoration(
labelText: "Enter Name:",
border: OutlineInputBorder(),
),
),
const SizedBox(height: 12),
TextField(
controller: _age,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
labelText: "Enter Age:",
border: OutlineInputBorder(),
),
),
const SizedBox(height: 12),
TextField(
controller: _id,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
labelText: "ID (for Update/Delete)",
border: OutlineInputBorder(),
),
),
const SizedBox(height: 12),
ElevatedButton(
onPressed: _addRecord,
child: const Text("Add Record"),
),
const SizedBox(height: 8),
ElevatedButton(
onPressed: _updateRecord,
child: const Text("Update Record"),
),
const SizedBox(height: 8),
ElevatedButton(
onPressed: _deleteRecord,
child: const Text("Delete Record"),
),
const SizedBox(height: 8),
ElevatedButton(
onPressed: _fetchRecords,
child: const Text("Show Records"),
),
const SizedBox(height: 20),
const Text(
"All Records:",
style: TextStyle(fontSize: 18, fontWeight: FontWeight.bold),
),
const SizedBox(height: 8),
..._records.map((r) => ListTile(
title: Text("ID: ${r['_id']} Name: ${r['name']} Age: ${r['age']}"),
)),
],
),
),
);
}
}
Step 4: Run the Application
flutter run
Operations Guide
Insert 5 Records:
- Enter name and age
- Click "Add Record"
- Repeat 5 times
Update Record:
- Enter ID in "ID" field
- Enter new name and age
- Click "Update Record"
Delete Record:
- Enter ID in "ID" field
- Click "Delete Record"
Show All Records:
- Click "Show Records" button
- All records display below buttons
Project Structure
lib/
├── main.dart # Main UI
└── database_helper.dart # Database operations
Objective
Create a registration form that collects user data on the first page and displays it on the second page when submit button is clicked.
Form Components:
- TextField: Name input
- Radio buttons: Gender selection
- Dropdown: City selection
- Checkboxes: Language selection
- Switch: Background color toggle
Step 1: Create Main Application (main.dart)
Create/modify file: lib/main.dart
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
),
home: const MyHomePage(title: 'Registration Form'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
// State variables
String? _gender;
bool _langEng = false;
bool _langMar = false;
bool _langHin = false;
List<String> langs = [];
String? _selectedCity;
final List<String> cities = ["Chennai", "Mumbai", "Delhi", "Kolkata", "Bangalore"];
final TextEditingController _namecon = TextEditingController();
bool _darkbkgrd = false;
// Submit form and navigate to result page
void submitForm() {
String name = _namecon.text;
langs.clear();
if (_langEng) langs.add("English");
if (_langMar) langs.add("Marathi");
if (_langHin) langs.add("Hindi");
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => ResultPage(
name: name,
gender: _gender ?? "Not Selected",
languages: langs,
city: _selectedCity ?? "Not Selected",
),
),
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: Text(widget.title),
),
body: Container(
color: _darkbkgrd ? Colors.lightBlueAccent : Colors.white,
child: Padding(
padding: const EdgeInsets.all(8.0),
child: Column(
children: [
// TextField for Name
TextField(
controller: _namecon,
decoration: const InputDecoration(
labelText: "Enter your Name:",
border: OutlineInputBorder(),
),
),
const SizedBox(height: 20),
// Radio buttons for Gender
const Text("Select Gender:"),
RadioListTile<String>(
title: const Text("Male"),
value: "Male",
groupValue: _gender,
onChanged: (newval) {
setState(() {
_gender = newval;
});
},
),
RadioListTile<String>(
title: const Text("Female"),
value: "Female",
groupValue: _gender,
onChanged: (newval) {
setState(() {
_gender = newval;
});
},
),
// Checkboxes for Languages
const Text("Languages known:"),
CheckboxListTile(
title: const Text("English"),
value: _langEng,
onChanged: (newval) {
setState(() {
_langEng = newval ?? false;
});
},
),
CheckboxListTile(
title: const Text("Hindi"),
value: _langHin,
onChanged: (newval) {
setState(() {
_langHin = newval ?? false;
});
},
),
CheckboxListTile(
title: const Text("Marathi"),
value: _langMar,
onChanged: (newval) {
setState(() {
_langMar = newval ?? false;
});
},
),
const SizedBox(height: 20),
// Dropdown for City
const Text("Select City"),
DropdownButton<String>(
value: _selectedCity,
hint: const Text("Select a City"),
items: cities
.map((city) => DropdownMenuItem(
value: city,
child: Text(city),
))
.toList(),
onChanged: (newval) {
setState(() {
_selectedCity = newval;
});
},
),
const SizedBox(height: 20),
// Submit Button
ElevatedButton(
onPressed: submitForm,
child: const Text("Submit Form"),
),
const SizedBox(height: 20),
// Switch for Background Color
SwitchListTile(
title: const Text("Dark Background"),
value: _darkbkgrd,
onChanged: (newval) {
setState(() {
_darkbkgrd = newval;
});
},
),
],
),
),
),
);
}
}
// Result Page to display submitted data
class ResultPage extends StatelessWidget {
final String name;
final String gender;
final List<String> languages;
final String city;
const ResultPage({
super.key,
required this.name,
required this.gender,
required this.languages,
required this.city,
});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("Result")),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text("Name: $name", style: const TextStyle(fontSize: 20)),
Text("Gender: $gender", style: const TextStyle(fontSize: 20)),
Text(
"Languages: ${languages.isEmpty ? "None" : languages.join(", ")}",
style: const TextStyle(fontSize: 20),
),
Text("City: $city", style: const TextStyle(fontSize: 20)),
],
),
),
);
}
}
Step 2: Run the Application
flutter run
Assignment 14: Flutter BMI Calculator
Objective
Create a BMI calculator with two text fields (weight, height), a calculate button, and display the result with BMI category.
Step 1: Create Main Application (main.dart)
Create/modify file: lib/main.dart
import 'package:flutter/material.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
colorScheme: ColorScheme.fromSeed(seedColor: Colors.deepPurple),
),
home: const MyHomePage(title: 'Body Mass Index Calculator'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key, required this.title});
final String title;
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
var textwcon = TextEditingController();
var texthcon = TextEditingController();
String s = "";
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Theme.of(context).colorScheme.inversePrimary,
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
// Weight TextField
TextField(
controller: textwcon,
decoration: const InputDecoration(
labelText: "Enter Weight in Kgs",
),
keyboardType: TextInputType.number,
style: const TextStyle(
fontSize: 22,
),
),
// Height TextField
TextField(
controller: texthcon,
decoration: const InputDecoration(
labelText: "Enter Height in Meters",
),
keyboardType: TextInputType.number,
style: const TextStyle(
fontSize: 22,
),
),
// Calculate Button
ElevatedButton(
onPressed: () {
setState(() {
double wei = double.parse(textwcon.text);
double hei = double.parse(texthcon.text);
double bmi = wei / (hei * hei);
print("Calculated BMI: $bmi");
String category;
if (bmi < 18.5) {
category = "Underweight";
} else if (bmi >= 18.5 && bmi < 24.9) {
category = "Normal Weight";
} else if (bmi >= 25 && bmi < 29.9) {
category = "Overweight";
} else {
category = "Obese";
}
s = "${bmi.toStringAsFixed(2)} $category";
});
},
child: const Text("Calculate"),
),
const SizedBox(height: 20),
// Result Display
Text(
"BMI: $s",
style: const TextStyle(
color: Colors.blue,
fontSize: 24,
),
),
],
),
),
);
}
}
Step 2: Run the Application
flutter run
How to Use
- Enter weight in kilograms (e.g., 70)
- Enter height in meters (e.g., 1.75)
- Click "Calculate" button
- View BMI result with category
BMI = Weight (kg) / (Height (m))²
BMI Categories
| BMI Range |
Category |
| < 18.5 |
Underweight |
| 18.5 - 24.9 |
Normal Weight |
| 25.0 - 29.9 |
Overweight |
| ≥ 30.0 |
Obese |
Example Calculations
Example 1:
- Weight: 70 kg
- Height: 1.75 m
- BMI: 70 / (1.75 × 1.75) = 22.86
- Category: Normal Weight
Example 2:
- Weight: 85 kg
- Height: 1.70 m
- BMI: 85 / (1.70 × 1.70) = 29.41
- Category: Overweight
Below is a clean, neat, ready-to-copy Notepad format for your Assignment 13 – Fetching Data using REST API (Volley, OkHttp, Retrofit) with:
✔ Steps
✔ JSON creation
✔ Permissions
✔ build.gradle dependencies
✔ activity_main.xml
✔ Full code for all 3 approaches
✔ Output sections (blank – since you add screenshot)
No emojis.
Assignment 13 – Fetching Data Using REST API (Android)
Create JSON Data (Employee)
Fields: eno, ename, dept, salary
Example JSON (JSONArray):
[
{
"eno": 1,
"ename": "John",
"dept": "IT",
"salary": 40000
},
{
"eno": 2,
"ename": "Sneha",
"dept": "HR",
"salary": 45000
}
]
Use any mock API service:
https://mocki.io
A. Using Volley Library
Step 1: Add Internet Permission
AndroidManifest.xml
<uses-permission android:name="android.permission.INTERNET"/>
Step 2: Add Volley Dependency (build.gradle.kts)
implementation("com.android.volley:volley:1.2.1")
Step 3: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fetch Data" />
<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="18sp"
android:padding="10dp" />
</LinearLayout>
Step 4: MainActivity.java
package com.alonex.volleyeg;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONObject;
public class MainActivity extends AppCompatActivity {
Button btnfetch;
TextView tv;
String url = "https://mocki.io/v1/9dc2d9d3-18fa-42ef-8e1a-8f9b7c881f0f";
JsonArrayRequest jsonArray;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.tv);
btnfetch = findViewById(R.id.button);
btnfetch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
fetchData();
}
});
}
private void fetchData() {
RequestQueue queue = Volley.newRequestQueue(this);
StringBuffer buffer = new StringBuffer();
jsonArray = new JsonArrayRequest(Request.Method.GET, url, null,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
JSONObject obj = null;
for (int i = 0; i < response.length(); i++) {
try {
obj = response.getJSONObject(i);
buffer.append("Employee Number: " + obj.getString("eno")).append("\n");
buffer.append("Name: " + obj.getString("ename")).append("\n");
buffer.append("Department: " + obj.getString("dept")).append("\n");
buffer.append("Salary: " + obj.getString("salary")).append("\n\n");
} catch (Exception e) {
e.printStackTrace();
}
}
tv.setText(buffer.toString());
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
tv.setText("Volley Error: " + error.getMessage());
}
});
queue.add(jsonArray);
}
}
Output:
(Attach screenshot)
B. Using OkHttp Library
{
"employees": [
{
"eno": 26,
"ename": "Thomas",
"dept": "HR",
"salary": 40000
}
]
}
Step 2: Add Internet Permission
<uses-permission android:name="android.permission.INTERNET"/>
Step 3: Add OkHttp Dependency
implementation("com.squareup.okhttp3:okhttp:4.11.0")
Step 4: activity_main.xml
(Same as previous)
Step 5: MainActivity.java
package com.alonex.okhttp;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
Button btnfetch;
TextView tv;
String url = "https://mocki.io/v1/a19b6146-e4c0-4009-a295-fe9d7c774d8a";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.tv);
btnfetch = findViewById(R.id.button);
btnfetch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
okhttpfetch();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
private void okhttpfetch() throws IOException {
OkHttpClient client = new OkHttpClient();
Request req = new Request.Builder().url(url).build();
client.newCall(req).enqueue(new Callback() {
@Override
public void onFailure(@NonNull Call call, @NonNull IOException e) {
call.cancel();
}
@Override
public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
String str = response.body().string();
StringBuffer buffer = new StringBuffer();
try {
JSONObject obj = new JSONObject(str);
JSONArray arr = obj.optJSONArray("employees");
for (int i = 0; i < arr.length(); i++) {
JSONObject emp = arr.getJSONObject(i);
buffer.append("E.No.: " + emp.getString("eno")).append("\n");
buffer.append("Name: " + emp.getString("ename")).append("\n");
buffer.append("Department: " + emp.getString("dept")).append("\n");
buffer.append("Salary: " + emp.getString("salary")).append("\n\n");
}
} catch (JSONException e) {
e.printStackTrace();
}
tv.setText(buffer.toString());
}
});
}
}
Output:
(Attach screenshot)
C. Using Retrofit Library
Step 1: Add Internet Permission
<uses-permission android:name="android.permission.INTERNET"/>
Step 2: Add Retrofit Dependencies
implementation("com.squareup.retrofit2:retrofit:2.9.0")
implementation("com.squareup.retrofit2:converter-gson:2.7.2")
Step 3: JSON Endpoint (JSONArray)
Example from mocki.io
Step 4: Api.java
package com.alonex.retrofit;
import java.util.List;
import retrofit2.Call;
import retrofit2.http.GET;
public interface Api {
String BASE_URL = "https://mocki.io/v1/";
@GET("4c36c134-bf06-4960-86dc-32ca7265e58d")
Call<List<employee>> getemployee();
}
Step 5: employee.java
package com.alonex.retrofit;
public class employee {
private int eno, salary;
private String ename, dept;
public employee(int eno, int salary, String ename, String dept) {
this.eno = eno;
this.salary = salary;
this.ename = ename;
this.dept = dept;
}
public int getEno() {
return eno;
}
public int getSalary() {
return salary;
}
public String getEname() {
return ename;
}
public String getDept() {
return dept;
}
}
Step 6: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/btn"
android:text="Fetch Data"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="18sp"
android:padding="10dp" />
</LinearLayout>
Step 7: MainActivity.java
package com.alonex.retrofit;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity {
TextView tv;
Button btn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.textView);
btn = findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
fetchData();
}
});
}
private void fetchData() {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(Api.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
Api api = retrofit.create(Api.class);
Call<List<employee>> call = api.getemployee();
call.enqueue(new Callback<List<employee>>() {
@Override
public void onResponse(Call<List<employee>> call, Response<List<employee>> response) {
List<employee> emp = response.body();
StringBuffer buff = new StringBuffer();
for (employee e : emp) {
buff.append("\n\n Employee No.: " + e.getEno());
buff.append("\n Employee Name: " + e.getEname());
buff.append("\n Department: " + e.getDept());
buff.append("\n Salary: " + e.getSalary());
}
tv.setText(buff);
}
@Override
public void onFailure(Call<List<employee>> call, Throwable t) {
Toast.makeText(getApplicationContext(), t.toString(), Toast.LENGTH_LONG).show();
}
});
}
}
Output:
(Attach screenshot)
If you want, I can also prepare this as a PDF or DOCX for printing/submission.
Below is a clean, neat, ready-to-copy Notepad format for your Assignment 13 – Fetching Data using REST API (Volley, OkHttp, Retrofit) with:
✔ Steps
✔ JSON creation
✔ Permissions
✔ build.gradle dependencies
✔ activity_main.xml
✔ Full code for all 3 approaches
✔ Output sections (blank – since you add screenshot)
No emojis.
Assignment 13 – Fetching Data Using REST API (Android)
Create JSON Data (Employee)
Fields: eno, ename, dept, salary
Example JSON (JSONArray):
[
{
"eno": 1,
"ename": "John",
"dept": "IT",
"salary": 40000
},
{
"eno": 2,
"ename": "Sneha",
"dept": "HR",
"salary": 45000
}
]
Use any mock API service:
https://mocki.io
A. Using Volley Library
Step 1: Add Internet Permission
AndroidManifest.xml
<uses-permission android:name="android.permission.INTERNET"/>
Step 2: Add Volley Dependency (build.gradle.kts)
implementation("com.android.volley:volley:1.2.1")
Step 3: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fetch Data" />
<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="18sp"
android:padding="10dp" />
</LinearLayout>
Step 4: MainActivity.java
package com.alonex.volleyeg;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONObject;
public class MainActivity extends AppCompatActivity {
Button btnfetch;
TextView tv;
String url = "https://mocki.io/v1/9dc2d9d3-18fa-42ef-8e1a-8f9b7c881f0f";
JsonArrayRequest jsonArray;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.tv);
btnfetch = findViewById(R.id.button);
btnfetch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
fetchData();
}
});
}
private void fetchData() {
RequestQueue queue = Volley.newRequestQueue(this);
StringBuffer buffer = new StringBuffer();
jsonArray = new JsonArrayRequest(Request.Method.GET, url, null,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
JSONObject obj = null;
for (int i = 0; i < response.length(); i++) {
try {
obj = response.getJSONObject(i);
buffer.append("Employee Number: " + obj.getString("eno")).append("\n");
buffer.append("Name: " + obj.getString("ename")).append("\n");
buffer.append("Department: " + obj.getString("dept")).append("\n");
buffer.append("Salary: " + obj.getString("salary")).append("\n\n");
} catch (Exception e) {
e.printStackTrace();
}
}
tv.setText(buffer.toString());
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
tv.setText("Volley Error: " + error.getMessage());
}
});
queue.add(jsonArray);
}
}
Output:
(Attach screenshot)
B. Using OkHttp Library
{
"employees": [
{
"eno": 26,
"ename": "Thomas",
"dept": "HR",
"salary": 40000
}
]
}
Step 2: Add Internet Permission
<uses-permission android:name="android.permission.INTERNET"/>
Step 3: Add OkHttp Dependency
implementation("com.squareup.okhttp3:okhttp:4.11.0")
Step 4: activity_main.xml
(Same as previous)
Step 5: MainActivity.java
package com.alonex.okhttp;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
Button btnfetch;
TextView tv;
String url = "https://mocki.io/v1/a19b6146-e4c0-4009-a295-fe9d7c774d8a";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.tv);
btnfetch = findViewById(R.id.button);
btnfetch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
okhttpfetch();
} catch (IOException e) {
e.printStackTrace();
}
}
});
}
private void okhttpfetch() throws IOException {
OkHttpClient client = new OkHttpClient();
Request req = new Request.Builder().url(url).build();
client.newCall(req).enqueue(new Callback() {
@Override
public void onFailure(@NonNull Call call, @NonNull IOException e) {
call.cancel();
}
@Override
public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
String str = response.body().string();
StringBuffer buffer = new StringBuffer();
try {
JSONObject obj = new JSONObject(str);
JSONArray arr = obj.optJSONArray("employees");
for (int i = 0; i < arr.length(); i++) {
JSONObject emp = arr.getJSONObject(i);
buffer.append("E.No.: " + emp.getString("eno")).append("\n");
buffer.append("Name: " + emp.getString("ename")).append("\n");
buffer.append("Department: " + emp.getString("dept")).append("\n");
buffer.append("Salary: " + emp.getString("salary")).append("\n\n");
}
} catch (JSONException e) {
e.printStackTrace();
}
tv.setText(buffer.toString());
}
});
}
}
Output:
(Attach screenshot)
C. Using Retrofit Library
Step 1: Add Internet Permission
<uses-permission android:name="android.permission.INTERNET"/>
Step 2: Add Retrofit Dependencies
implementation("com.squareup.retrofit2:retrofit:2.9.0")
implementation("com.squareup.retrofit2:converter-gson:2.7.2")
Step 3: JSON Endpoint (JSONArray)
Example from mocki.io
Step 4: Api.java
package com.alonex.retrofit;
import java.util.List;
import retrofit2.Call;
import retrofit2.http.GET;
public interface Api {
String BASE_URL = "https://mocki.io/v1/";
@GET("4c36c134-bf06-4960-86dc-32ca7265e58d")
Call<List<employee>> getemployee();
}
Step 5: employee.java
package com.alonex.retrofit;
public class employee {
private int eno, salary;
private String ename, dept;
public employee(int eno, int salary, String ename, String dept) {
this.eno = eno;
this.salary = salary;
this.ename = ename;
this.dept = dept;
}
public int getEno() {
return eno;
}
public int getSalary() {
return salary;
}
public String getEname() {
return ename;
}
public String getDept() {
return dept;
}
}
Step 6: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/btn"
android:text="Fetch Data"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="18sp"
android:padding="10dp" />
</LinearLayout>
Step 7: MainActivity.java
package com.alonex.retrofit;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity {
TextView tv;
Button btn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.textView);
btn = findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
fetchData();
}
});
}
private void fetchData() {
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(Api.BASE_URL)
.addConverterFactory(GsonConverterFactory.create())
.build();
Api api = retrofit.create(Api.class);
Call<List<employee>> call = api.getemployee();
call.enqueue(new Callback<List<employee>>() {
@Override
public void onResponse(Call<List<employee>> call, Response<List<employee>> response) {
List<employee> emp = response.body();
StringBuffer buff = new StringBuffer();
for (employee e : emp) {
buff.append("\n\n Employee No.: " + e.getEno());
buff.append("\n Employee Name: " + e.getEname());
buff.append("\n Department: " + e.getDept());
buff.append("\n Salary: " + e.getSalary());
}
tv.setText(buff);
}
@Override
public void onFailure(Call<List<employee>> call, Throwable t) {
Toast.makeText(getApplicationContext(), t.toString(), Toast.LENGTH_LONG).show();
}
});
}
}
Below is your Assignment 12 – GPS Location in clean step-by-step guide format, ready to copy into Notepad.
Assignment 12 – GPS Location
Write an Android program to show the current location.
Step 1: Add Permissions in AndroidManifest.xml
(Add inside the <manifest> tag)
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.INTERNET"/>
Step 2: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/btntrack"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Track Location" />
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20dp"
android:textSize="18sp" />
</LinearLayout>
Step 3: MainActivity.java
package com.alonex.gpslocation;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Address;
import android.location.Geocoder;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.util.List;
public class MainActivity extends AppCompatActivity implements LocationListener {
TextView tv;
Button btnt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv = findViewById(R.id.textView);
btnt = findViewById(R.id.btntrack);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 200);
}
btnt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
getLocation();
}
});
}
private void getLocation() {
LocationManager manager = (LocationManager)
getApplicationContext().getSystemService(LOCATION_SERVICE);
if (ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED &&
ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
manager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
5000,
5,
MainActivity.this
);
}
@Override
public void onLocationChanged(@NonNull Location location) {
try {
Geocoder geo = new Geocoder(this);
double lat = location.getLatitude();
double lon = location.getLongitude();
List<Address> addressList = geo.getFromLocation(lat, lon, 1);
String address = addressList.get(0).getAddressLine(0);
tv.setText("Latitude: " + lat + "\n"
+ "Longitude: " + lon + "\n"
+ "Address: " + address);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Output:
(Add screenshot here)
If you want, I can prepare Assignment 13 again in this same clean format.
Below is Assignment 11 – Audio Video Program in your required clean guide format (steps + XML + code, no explanation, no output screenshot).
Assignment 11 – Audio Video Program
Write an Android program to play audio and video.
Create a folder:
app/src/main/res/raw/
Add:
sample.mp3 (for audio)
samplev.mp4 (for video)
Step 2: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/btnplay"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Play Audio" />
<Button
android:id="@+id/btnpause"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Pause Audio" />
<Button
android:id="@+id/btnstop"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Stop Audio" />
<VideoView
android:id="@+id/vv"
android:layout_width="match_parent"
android:layout_height="250dp"
android:layout_marginTop="20dp" />
<Button
android:id="@+id/btnplayv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Play Video" />
</LinearLayout>
Step 3: MainActivity.java
package com.alonex.audiovideo;
import androidx.appcompat.app.AppCompatActivity;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.MediaController;
import android.widget.Toast;
import android.widget.VideoView;
public class MainActivity extends AppCompatActivity {
VideoView vv;
Button aplay, apause, astop, vplay;
MediaPlayer mp;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
vv = findViewById(R.id.vv);
aplay = findViewById(R.id.btnplay);
apause = findViewById(R.id.btnpause);
astop = findViewById(R.id.btnstop);
vplay = findViewById(R.id.btnplayv);
aplay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
playAudio();
}
});
apause.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mp != null) {
mp.pause();
Toast.makeText(getApplicationContext(), "Audio Paused", Toast.LENGTH_LONG).show();
}
}
});
astop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mp != null) {
mp.stop();
mp = null;
Toast.makeText(getApplicationContext(), "Audio Stopped", Toast.LENGTH_LONG).show();
}
}
});
vplay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
playVideo();
}
});
}
private void playVideo() {
String path = "android.resource://" + getPackageName() + "/" + R.raw.samplev;
Uri uri = Uri.parse(path);
vv.setVideoURI(uri);
MediaController mc = new MediaController(this);
vv.setMediaController(mc);
vv.start();
mc.setAnchorView(vv);
Toast.makeText(getApplicationContext(), "Video played", Toast.LENGTH_LONG).show();
}
private void playAudio() {
if (mp == null) {
mp = MediaPlayer.create(getApplicationContext(), R.raw.sample);
mp.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
mp.release();
}
});
}
mp.start();
Toast.makeText(getApplicationContext(), "Audio Played", Toast.LENGTH_LONG).show();
}
}
Below is Assignment 10 – Image Animation & Processing in your clean copy-paste guide format.
Assignment 10 – Image Animation & Processing
Write an Android program to perform simple image animations (translate, rotate, scale, fade), invert image, and monochrome image.
Step 1: Add Image in Drawable Folder
Place an image named:
pixels.png (or .jpg)
Location:
app/src/main/res/drawable/pixels.png
Step 2: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="20dp">
<ImageView
android:id="@+id/imageView"
android:layout_width="250dp"
android:layout_height="250dp"
android:layout_gravity="center"
android:src="@drawable/pixels" />
<Button
android:id="@+id/btntranslate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Translate" />
<Button
android:id="@+id/btnrotat"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Rotate" />
<Button
android:id="@+id/btnfade"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fade" />
<Button
android:id="@+id/btnsca"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Scale" />
<Button
android:id="@+id/btninv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Invert Image" />
<Button
android:id="@+id/monobtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Monochrome" />
<Button
android:id="@+id/btnreset"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Reset" />
</LinearLayout>
</ScrollView>
Step 3: MainActivity.java
package com.alonex.animationeg;
import androidx.appcompat.app.AppCompatActivity;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
Button btntrans, btnrot, btnfade, btnsc, btninv, btnmono, btnres;
ImageView img;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btntrans = findViewById(R.id.btntranslate);
btnrot = findViewById(R.id.btnrotat);
btnfade = findViewById(R.id.btnfade);
btnsc = findViewById(R.id.btnsca);
img = findViewById(R.id.imageView);
btninv = findViewById(R.id.btninv);
btnmono = findViewById(R.id.monobtn);
btnres = findViewById(R.id.btnreset);
btnres.setOnClickListener(v -> resetImage());
btnmono.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Drawable d2 = getResources().getDrawable(R.drawable.pixels, getTheme());
Bitmap bitimg = ((BitmapDrawable) d2).getBitmap();
Bitmap newimg = toGrayscale(bitimg);
img.setImageBitmap(newimg);
}
});
btntrans.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
translate(v);
}
});
btnsc.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
scale(v);
}
});
btnrot.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
rotate();
}
});
btnfade.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
fade(v);
}
});
btninv.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Drawable d2 = getResources().getDrawable(R.drawable.pixels, getTheme());
Bitmap bitimg = ((BitmapDrawable) d2).getBitmap();
Bitmap newimg = invertImage(bitimg);
img.setImageBitmap(newimg);
}
});
}
private void resetImage() {
img.setAlpha(1f);
img.setRotation(0f);
img.setScaleX(1f);
img.setScaleY(1f);
img.setX(0f);
img.setY(0f);
img.setImageResource(R.drawable.pixels);
}
private Bitmap invertImage(Bitmap bitimg) {
Bitmap finalimg = Bitmap.createBitmap(bitimg.getWidth(), bitimg.getHeight(), bitimg.getConfig());
int A, R, G, B;
int pixelcolor;
int h = bitimg.getHeight();
int w = bitimg.getWidth();
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
pixelcolor = bitimg.getPixel(x, y);
A = Color.alpha(pixelcolor);
R = 255 - Color.red(pixelcolor);
G = 255 - Color.green(pixelcolor);
B = 255 - Color.blue(pixelcolor);
finalimg.setPixel(x, y, Color.argb(A, R, G, B));
}
}
return finalimg;
}
private void fade(View v) {
ObjectAnimator alphani = ObjectAnimator.ofFloat(img, View.ALPHA, 1.0f, 0.5f);
alphani.setDuration(500);
AnimatorSet set = new AnimatorSet();
set.playTogether(alphani);
set.start();
}
private void rotate() {
ObjectAnimator r = ObjectAnimator.ofFloat(img, "rotation", 0f, 270f);
r.setDuration(500);
AnimatorSet set = new AnimatorSet();
set.playTogether(r);
set.start();
}
private void scale(View v) {
ObjectAnimator scalex = ObjectAnimator.ofFloat(img, "scaleX", 2f);
ObjectAnimator scaley = ObjectAnimator.ofFloat(img, "scaleY", 2f);
scalex.setDuration(500);
scaley.setDuration(500);
AnimatorSet set = new AnimatorSet();
set.playTogether(scalex, scaley);
set.start();
}
private void translate(View v) {
ObjectAnimator anix = ObjectAnimator.ofFloat(img, "x", 500);
ObjectAnimator aniy = ObjectAnimator.ofFloat(img, "y", 100);
anix.setDuration(500);
aniy.setDuration(500);
AnimatorSet set = new AnimatorSet();
set.playTogether(anix, aniy);
set.start();
}
private Bitmap toGrayscale(Bitmap bitimg) {
Bitmap finalimg = Bitmap.createBitmap(bitimg.getWidth(), bitimg.getHeight(), bitimg.getConfig());
int A, R, G, B;
int pixelcolor;
int h = bitimg.getHeight();
int w = bitimg.getWidth();
for (int y = 0; y < h; y++) {
for (int x = 0; x < w; x++) {
pixelcolor = bitimg.getPixel(x, y);
A = Color.alpha(pixelcolor);
R = Color.red(pixelcolor);
G = Color.green(pixelcolor);
B = Color.blue(pixelcolor);
int gray = (int) (0.299 * R + 0.587 * G + 0.114 * B);
finalimg.setPixel(x, y, Color.argb(A, gray, gray, gray));
}
}
return finalimg;
}
}
Output:
- Translate
- Rotate
- Fade
- Scale
- Invert
- Monochrome
Below is Assignment 9 – Firebase Realtime Database in your clean step-by-step guide format.
Assignment 9 – Firebase Realtime Database
Create Employee table with fields: eno, ename, salary, dept
Perform: Insert, Show, Delete, Update
Step 1: Setting up Firebase in Android Studio
1. Open:
Tools → Firebase
2. Select:
Realtime Database → Get started with Realtime Database (Java)
3. Click:
Connect to Firebase
4. Create Firebase project by entering a project name.
5. After connection, click:
Add the Realtime Database SDK to your app → Accept Changes
Step 2: Create Firebase Realtime Database
1. Go to Firebase Console → Realtime Database
2. Click Create Database
3. Choose region
4. Select Start in Test Mode
5. Make sure test rules allow read/write:
{
"rules": {
".read": true,
".write": true
}
}
Step 3: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="20dp">
<EditText
android:id="@+id/edtno"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Employee No" />
<EditText
android:id="@+id/edtname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Employee Name" />
<EditText
android:id="@+id/edtsal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Salary" />
<Spinner
android:id="@+id/deptspin"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="@+id/addbtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add Record" />
<Button
android:id="@+id/displaybtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Show Records" />
<Button
android:id="@+id/deletebtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Delete Record" />
<Button
android:id="@+id/updatebtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Update Record" />
<ListView
android:id="@+id/lv"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
Step 4: Employee.java
package com.alonex.firebaseeg;
public class Employee {
private String id;
private int eno, salary;
private String ename, department;
public Employee() {
}
public Employee(String id, int eno, String ename, int salary, String department) {
this.id = id;
this.eno = eno;
this.ename = ename;
this.salary = salary;
this.department = department;
}
public int getSalary() {
return salary;
}
public void setSalary(int salary) {
this.salary = salary;
}
public String getDepartment() {
return department;
}
public void setDepartment(String department) {
this.department = department;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public int getEno() {
return eno;
}
public void setEno(int eno) {
this.eno = eno;
}
public String getEname() {
return ename;
}
public void setEname(String ename) {
this.ename = ename;
}
}
Step 5: MainActivity.java
package com.alonex.firebaseeg;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.Toast;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
EditText eno, ename, salary;
Spinner dept;
Button add, display, delete, update;
ListView lv;
List<Employee> employeeList = new ArrayList<>();
DatabaseReference dbRef;
String selectedId = "";
String selectedDept = "";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
eno = findViewById(R.id.edtno);
ename = findViewById(R.id.edtname);
salary = findViewById(R.id.edtsal);
add = findViewById(R.id.addbtn);
display = findViewById(R.id.displaybtn);
delete = findViewById(R.id.deletebtn);
update = findViewById(R.id.updatebtn);
String[] dpts = {"Administration", "IT", "Marketing", "Sales", "Finance"};
dept = findViewById(R.id.deptspin);
ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
android.R.layout.simple_spinner_item, dpts);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
dept.setAdapter(adapter);
dept.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
selectedDept = parent.getItemAtPosition(position).toString();
}
@Override
public void onNothingSelected(AdapterView<?> parent) {}
});
lv = findViewById(R.id.lv);
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int i, long l) {
Employee e = employeeList.get(i);
ename.setText(e.getEname());
eno.setText(String.valueOf(e.getEno()));
selectedId = e.getId();
}
});
FirebaseDatabase database = FirebaseDatabase.getInstance();
dbRef = database.getReference("employee");
add.setOnClickListener(v -> addRecord());
display.setOnClickListener(v -> showAll());
delete.setOnClickListener(v -> deleteRecord());
update.setOnClickListener(v -> updateRecord());
}
private void addRecord() {
String name = ename.getText().toString();
int no = Integer.parseInt(eno.getText().toString());
int sal = Integer.parseInt(salary.getText().toString());
String id = dbRef.push().getKey();
Employee emp = new Employee(id, no, name, sal, selectedDept);
dbRef.child(id).setValue(emp);
Toast.makeText(getApplicationContext(), "Record Added", Toast.LENGTH_LONG).show();
}
private void showAll() {
dbRef.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
employeeList.clear();
for (DataSnapshot snp : snapshot.getChildren()) {
Employee emp = snp.getValue(Employee.class);
employeeList.add(emp);
}
List<String> disp = new ArrayList<>();
for (Employee e : employeeList) {
disp.add("Emp No: " + e.getEno() +
"\n Name: " + e.getEname() +
"\n Salary: " + e.getSalary() +
"\n Department: " + e.getDepartment());
}
ArrayAdapter<String> adapter = new ArrayAdapter<>(getApplicationContext(),
android.R.layout.simple_list_item_1, disp);
lv.setAdapter(adapter);
if (disp.isEmpty()) {
Toast.makeText(getApplicationContext(), "No records found",
Toast.LENGTH_SHORT).show();
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {}
});
}
private void deleteRecord() {
if (!selectedId.isEmpty()) {
dbRef.child(selectedId).removeValue();
Toast.makeText(getApplicationContext(), "Record Deleted", Toast.LENGTH_LONG).show();
showAll();
} else {
Toast.makeText(getApplicationContext(), "Please select a Record to Delete",
Toast.LENGTH_LONG).show();
}
}
private void updateRecord() {
if (!selectedId.isEmpty()) {
String s = ename.getText().toString();
int sal = Integer.parseInt(salary.getText().toString());
int i = Integer.parseInt(eno.getText().toString());
Employee e1 = new Employee(selectedId, i, s, sal, selectedDept);
dbRef.child(selectedId).setValue(e1);
Toast.makeText(getApplicationContext(), "Record Updated",
Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(),
"Please select a Record to Update", Toast.LENGTH_LONG).show();
}
}
}
Output:
- Insert a Record
- Display Records
- Delete a Record
- Update a Record
Below is Assignment 8 – SQLite Database rewritten in your clean “exam-ready / practical file” format — step-by-step guide + all code, same style as Assignment 9.
Just copy–paste to your Notepad.
Assignment 8 – SQLite Database
Create Student table with fields:
rno, name, gender, score1, score2
Perform: Create, Insert, Show All, Search, Delete, Update
mainActivity.xml
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="16dp">
<EditText
android:id="@+id/edtrno"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter Roll No"
android:inputType="number"
android:layout_marginBottom="8dp" />
<EditText
android:id="@+id/edtname"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter Name"
android:layout_marginBottom="8dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Gender"
android:layout_marginBottom="4dp" />
<RadioGroup
android:id="@+id/genderrg"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginBottom="8dp">
<RadioButton
android:id="@+id/malerb"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Male" />
<RadioButton
android:id="@+id/femalerb"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Female"
android:layout_marginStart="16dp" />
</RadioGroup>
<EditText
android:id="@+id/edtscore1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Score 1"
android:inputType="number"
android:layout_marginBottom="8dp" />
<EditText
android:id="@+id/edtscore2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Score 2"
android:inputType="number"
android:layout_marginBottom="12dp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="3"
android:layout_marginBottom="8dp">
<Button
android:id="@+id/btnadd"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Add" />
<Button
android:id="@+id/btnview"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Show All" />
<Button
android:id="@+id/btnsearch"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Search" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:weightSum="2"
android:layout_marginBottom="8dp">
<Button
android:id="@+id/btndelete"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Delete" />
<Button
android:id="@+id/btnupdate"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="Update" />
</LinearLayout>
<TextView
android:id="@+id/tv2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Result will appear here"
android:padding="8dp"
android:background="#EEEEEE" />
</LinearLayout>
** mainActivity2 **
<TextView
android:id="@+id/textViewRecords"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="All Records will appear here"
android:textSize="16sp" />
**Step 1: Creating SQLite Database
using SQLiteOpenHelper**
dbHandler.java
package com.alone_x.sqlitedb;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import androidx.annotation.Nullable;
public class dbHandler extends SQLiteOpenHelper {
static String DB_NAME = "student.db";
static String TAB_NAME = "student";
public dbHandler(@Nullable Context context){
super(context,DB_NAME,null,1);
}
@Override
public void onCreate(SQLiteDatabase db) {
String query = "CREATE TABLE " + TAB_NAME +
" (rno integer primary key, name text, gender text, score1 integer, score2 integer)";
db.execSQL(query);
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
}
public boolean saveData(int roll, String name, String gender, int score1, int score2){
SQLiteDatabase db = getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("rno", roll);
cv.put("name", name);
cv.put("gender", gender);
cv.put("score1", score1);
cv.put("score2", score2);
long insert = db.insert(TAB_NAME, null, cv);
return insert != -1;
}
public Cursor readData(){
SQLiteDatabase db = this.getReadableDatabase();
return db.rawQuery("SELECT * FROM " + TAB_NAME, null);
}
public Cursor searchData(int rno){
SQLiteDatabase db = this.getReadableDatabase();
return db.rawQuery("SELECT * FROM " + TAB_NAME + " WHERE rno=" + rno, null);
}
public int deleteRecord(String name){
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TAB_NAME, "name=?", new String[]{name});
}
public boolean updateRecord(int rno, String name, String gender, int score1, int score2){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put("rno", rno);
if(name != null && !name.isEmpty()) cv.put("name", name);
if(gender != null && !gender.isEmpty()) cv.put("gender", gender);
if(score1 != -1) cv.put("score1", score1);
if(score2 != -1) cv.put("score2", score2);
int update = db.update(TAB_NAME, cv, "rno=?", new String[]{String.valueOf(rno)});
return update > 0;
}
}
Step 2: MainActivity.java (UI + CRUD Operations)
package com.alone_x.sqlitedb;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity extends AppCompatActivity {
EditText rno, name, score1, score2;
RadioGroup genderrg;
RadioButton malerb, femalerb;
Button btnadd, btnview, btndel, btnupd, btnsrch;
TextView tv;
dbHandler connection;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
rno = findViewById(R.id.edtrno);
name = findViewById(R.id.edtname);
score1 = findViewById(R.id.edtscore1);
score2 = findViewById(R.id.edtscore2);
genderrg = findViewById(R.id.genderrg);
malerb = findViewById(R.id.malerb);
femalerb = findViewById(R.id.femalerb);
btnadd = findViewById(R.id.btnadd);
btnview = findViewById(R.id.btnview);
btndel = findViewById(R.id.btndelete);
btnupd = findViewById(R.id.btnupdate);
btnsrch = findViewById(R.id.btnsearch);
tv = findViewById(R.id.tv2);
malerb.setChecked(true);
connection = new dbHandler(this);
connection.getWritableDatabase();
btnadd.setOnClickListener(v -> {
int no = Integer.parseInt(rno.getText().toString());
String sname = name.getText().toString();
int selectedId = genderrg.getCheckedRadioButtonId();
RadioButton selectedRB = findViewById(selectedId);
String gender = selectedRB.getText().toString();
int scoreone = Integer.parseInt(score1.getText().toString());
int scoretwo = Integer.parseInt(score2.getText().toString());
boolean b = connection.saveData(no, sname, gender, scoreone, scoretwo);
Toast.makeText(getApplicationContext(), b ? "Record Created" : "Record Not Created", Toast.LENGTH_LONG).show();
});
btnview.setOnClickListener(v -> {
Cursor c = connection.readData();
if(c.getCount() == 0){
Toast.makeText(getApplicationContext(), "No Records", Toast.LENGTH_LONG).show();
} else {
StringBuilder records = new StringBuilder();
while(c.moveToNext()){
records.append("R.No.: ").append(c.getInt(c.getColumnIndexOrThrow("rno"))).append("\n");
records.append("Name: ").append(c.getString(c.getColumnIndexOrThrow("name"))).append("\n");
records.append("Gender: ").append(c.getString(c.getColumnIndexOrThrow("gender"))).append("\n");
records.append("Score1: ").append(c.getInt(c.getColumnIndexOrThrow("score1"))).append("\n");
records.append("Score2: ").append(c.getInt(c.getColumnIndexOrThrow("score2"))).append("\n");
records.append("--------------------\n");
}
c.close();
Intent intent = new Intent(MainActivity.this, MainActivity2.class);
intent.putExtra("records", records.toString());
startActivity(intent);
}
});
btndel.setOnClickListener(v -> {
String sname = name.getText().toString();
if(sname.isEmpty()){
Toast.makeText(getApplicationContext(), "Enter Name", Toast.LENGTH_SHORT).show();
return;
}
int deleted = connection.deleteRecord(sname);
if(deleted > 0){
rno.setText("");
name.setText("");
score1.setText("");
score2.setText("");
Toast.makeText(getApplicationContext(), "Record Deleted", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "No Record found", Toast.LENGTH_LONG).show();
}
});
btnsrch.setOnClickListener(v -> {
String rollStr = rno.getText().toString();
if(rollStr.isEmpty()){
Toast.makeText(getApplicationContext(), "Enter R.No", Toast.LENGTH_SHORT).show();
return;
}
int roll = Integer.parseInt(rollStr);
Cursor c = connection.searchData(roll);
if(c.getCount() == 0){
Toast.makeText(getApplicationContext(), "No Records", Toast.LENGTH_LONG).show();
} else if(c.moveToFirst()){
String sname = c.getString(c.getColumnIndexOrThrow("name"));
String gender = c.getString(c.getColumnIndexOrThrow("gender"));
int s1 = c.getInt(c.getColumnIndexOrThrow("score1"));
int s2 = c.getInt(c.getColumnIndexOrThrow("score2"));
name.setText(sname);
score1.setText(String.valueOf(s1));
score2.setText(String.valueOf(s2));
if(gender.equalsIgnoreCase("Male"))
malerb.setChecked(true);
else
femalerb.setChecked(true);
tv.setText("Name: " + sname +
"\nGender: " + gender +
"\nScore1: " + s1 +
"\nScore2: " + s2);
}
c.close();
});
btnupd.setOnClickListener(v -> {
String roll = rno.getText().toString();
if(roll.isEmpty()){
Toast.makeText(getApplicationContext(), "Enter R.NO.", Toast.LENGTH_LONG).show();
return;
}
int rollno = Integer.parseInt(roll);
String sname = name.getText().toString();
int selectedId = genderrg.getCheckedRadioButtonId();
RadioButton selectedRB = findViewById(selectedId);
String gender = selectedRB.getText().toString();
String scoreone = score1.getText().toString();
String scoretwo = score2.getText().toString();
int sc1 = scoreone.isEmpty() ? -1 : Integer.parseInt(scoreone);
int sc2 = scoretwo.isEmpty() ? -1 : Integer.parseInt(scoretwo);
boolean b = connection.updateRecord(rollno, sname, gender, sc1, sc2);
Toast.makeText(getApplicationContext(),
b ? "Record Updated" : "Record Not Updated",
Toast.LENGTH_LONG).show();
});
}
}
Step 3: MainActivity2.java (Display Page)
package com.alone_x.sqlitedb;
import android.os.Bundle;
import android.widget.TextView;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity2 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main2);
TextView textView = findViewById(R.id.textViewRecords);
String records = getIntent().getStringExtra("records");
if(records != null && !records.isEmpty()){
textView.setText(records);
} else {
textView.setText("No Records to display");
}
}
}
OUTPUT Operations
1. Creating / Inserting Records
2. Showing All Records (Next Activity)
3. Searching for a Record (By rno)
4. Deleting a Record (By name)
5. Updating a Record
SQLite Database File Location (Android Emulator Path)
/data/data/<your-package-name>/databases/student.db
If you want, I can also format Assignment 7 or 6 in the same style.
Below is Assignment 7 – File Storage (Internal & External) rewritten in your clean practical-file format (steps + code, no explanation).
Just copy–paste to Notepad.
Assignment 7 – File Storage (Internal & External Storage)
Perform the following operations:
✔ Save to Internal Storage
✔ Retrieve from Internal Storage
✔ Save to External Storage
✔ Retrieve from External Storage
** mainActivity.xml
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<!-- File Name -->
<EditText
android:id="@+id/editTextText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter File Name"
android:layout_marginBottom="10dp" />
<!-- Content to Store -->
<EditText
android:id="@+id/editTextMultiLine"
android:layout_width="match_parent"
android:layout_height="150dp"
android:gravity="start|top"
android:hint="Enter content here"
android:inputType="textMultiLine"
android:background="@android:color/darker_gray"
android:padding="10dp"
android:layout_marginBottom="20dp" />
<!-- Internal Storage Buttons -->
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Save to Internal Storage"
android:layout_marginBottom="10dp" />
<Button
android:id="@+id/button2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Retrieve from Internal Storage"
android:layout_marginBottom="25dp" />
<!-- External Storage Buttons -->
<Button
android:id="@+id/buttonextstr"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Save to External Storage"
android:layout_marginBottom="10dp" />
<Button
android:id="@+id/buttonextret"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Retrieve from External Storage" />
</LinearLayout>
** mainActivity2.xml **
<!-- File Name -->
<TextView
android:id="@+id/textView2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="File Name"
android:textStyle="bold"
android:textSize="18sp"
android:layout_marginBottom="10dp" />
<!-- File Content -->
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="File Content"
android:textSize="16sp"
android:padding="10dp"
android:background="#DDDDDD"
android:minHeight="200dp"
android:gravity="top"
android:layout_marginBottom="20dp" />
<!-- Go Back Button -->
<Button
android:id="@+id/button3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Go Back" />
Step 1: MainActivity.java
package com.alonex.filestorage;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
public class MainActivity extends AppCompatActivity {
EditText edt, fname;
File myFile;
Button strbtn, retrievebtn, btnextstr, btnextret;
String dirname = "pixels";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edt = findViewById(R.id.editTextMultiLine);
fname = findViewById(R.id.editTextText);
strbtn = findViewById(R.id.button);
retrievebtn = findViewById(R.id.button2);
btnextstr = findViewById(R.id.buttonextstr);
btnextret = findViewById(R.id.buttonextret);
Intent go = new Intent(this, MainActivity2.class);
strbtn.setOnClickListener(v ->
saveToInternal(fname.getText().toString(), edt.getText().toString()));
retrievebtn.setOnClickListener(v -> {
String fcon = readFromInternal(fname.getText().toString());
go.putExtra("fname", fname.getText().toString());
go.putExtra("content", fcon);
startActivity(go);
});
btnextstr.setOnClickListener(v ->
saveToExternal(fname.getText().toString(), edt.getText().toString()));
btnextret.setOnClickListener(v -> {
String fcon = readFromExternal(fname.getText().toString());
go.putExtra("fname", fname.getText().toString());
go.putExtra("content", fcon);
startActivity(go);
});
}
private String readFromExternal(String fname) {
String extStorageState = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(extStorageState)
& !Environment.MEDIA_MOUNTED_READ_ONLY.equals(extStorageState)) {
myFile = new File(getExternalFilesDir(dirname), fname);
}
String content = "";
try {
FileInputStream fis = new FileInputStream(myFile);
DataInputStream dis = new DataInputStream(fis);
BufferedReader buffer = new BufferedReader(new InputStreamReader(dis));
String line;
while ((line = buffer.readLine()) != null) {
content += "\n" + line;
}
dis.close();
} catch (Exception e) {
e.printStackTrace();
}
return content;
}
private void saveToExternal(String fname, String content) {
String extStorageState = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(extStorageState)
& !Environment.MEDIA_MOUNTED_READ_ONLY.equals(extStorageState)) {
myFile = new File(getExternalFilesDir(dirname), fname);
}
try {
FileOutputStream fos = new FileOutputStream(myFile);
fos.write(content.getBytes());
fos.close();
Toast.makeText(getApplicationContext(), "Content Saved Successfully",
Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
}
}
private String readFromInternal(String fname) {
String fcontent = "";
try {
FileInputStream fis = openFileInput(fname);
InputStreamReader reader = new InputStreamReader(fis);
char buffer[] = new char[256];
int charRead;
while ((charRead = reader.read(buffer)) > 0) {
String rs = String.copyValueOf(buffer, 0, charRead);
fcontent += rs;
}
} catch (Exception e) {
e.printStackTrace();
}
return fcontent;
}
private void saveToInternal(String fname, String content) {
try {
FileOutputStream fos = openFileOutput(fname, MODE_PRIVATE);
OutputStreamWriter writer = new OutputStreamWriter(fos);
writer.write(content);
writer.close();
Toast.makeText(getApplicationContext(), "Content Saved",
Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
}
}
}
Step 2: MainActivity2.java
package com.alonex.filestorage;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity2 extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
Intent intent = getIntent();
String text = intent.getStringExtra("content");
String filename = intent.getStringExtra("fname");
TextView tv = findViewById(R.id.textView);
TextView fname = findViewById(R.id.textView2);
fname.setText(filename);
tv.setText(text);
Intent back = new Intent(this, MainActivity.class);
Button goback = findViewById(R.id.button3);
goback.setOnClickListener(v -> startActivity(back));
}
}
OUTPUT Paths
Internal Storage File Path:
/data/data/com.<packagename>/files/<filename>
External Storage File Path:
/sdcard/Android/data/com.<packagename>/files/pixels/<filename>
Below is Assignment 6 – Notification rewritten in the same clean practical-file format (steps + code, no explanation).
Assignment 6 – Notification
Write an Android program to display a notification.
Step 1: Add Permission in AndroidManifest.xml
(Add this inside <manifest> tag)
<uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
Step 2: MainActivity.java
package com.alonex.notification;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.NotificationCompat;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
NotificationManager nm;
private void notifyy() {
NotificationCompat.Builder b =
new NotificationCompat.Builder(this, "CHANNEL1");
b.setSmallIcon(R.drawable.baseline_notifications_none_24);
b.setContentTitle("Website");
b.setContentText("Show me the Webpage");
b.setAutoCancel(true);
b.setPriority(NotificationManager.IMPORTANCE_HIGH);
Intent notify_intent = new Intent(Intent.ACTION_VIEW,
Uri.parse("https://pixelstechfest.in"));
notify_intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
PendingIntent pndIN = PendingIntent.getActivity(
this, 0, notify_intent, PendingIntent.FLAG_IMMUTABLE
);
b.setContentIntent(pndIN);
nm.notify(0, b.build());
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btn = findViewById(R.id.button);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
NotificationChannel ch =
new NotificationChannel("CHANNEL1",
"Pixels",
NotificationManager.IMPORTANCE_HIGH);
ch.setDescription("Channel 1");
nm = (NotificationManager)
getSystemService(Context.NOTIFICATION_SERVICE);
nm.createNotificationChannel(ch);
}
btn.setOnClickListener(v -> notifyy());
}
}
Step 3: activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical"
android:padding="20dp">
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Show Notification" />
</LinearLayout>
OUTPUT
When the button is clicked, a notification appears.
On clicking the notification, it opens:
https://pixelstechfest.in
Shared Prefs
View->Tool Windows->Device Explorer->data->data->package name
package com.example.sharedpref;
import android.os.Bundle;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
import androidx.appcompat.app.AppCompatActivity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;
import androidx.appcompat.app.AlertDialog;
public class MainActivity extends AppCompatActivity {
private EditText etUsername, etPassword;
private Button btnSignIn;
private CheckBox cbRememberMe;
private int wrongAttempts = 0;
private static final int MAX_ATTEMPTS = 3;
private static final String PASSWORD = "admin123";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
etUsername = findViewById(R.id.etUsername);
etPassword = findViewById(R.id.etPassword);
btnSignIn = findViewById(R.id.btnSignIn);
cbRememberMe = findViewById(R.id.cbRememberMe);
loadSavedCredentials();
btnSignIn.setOnClickListener(v -> attemptLogin());
if (wrongAttempts >= MAX_ATTEMPTS) {
btnSignIn.setEnabled(false);
showMaxAttemptsDialog();
}
}
private void loadSavedCredentials() {
SharedPreferences prefs = getSharedPreferences("login_prefs", MODE_PRIVATE);
boolean rememberMe = prefs.getBoolean("remember_me", false);
if (rememberMe) {
String username = prefs.getString("username", "");
etUsername.setText(username);
cbRememberMe.setChecked(true);
}
}
private void attemptLogin() {
String password = etPassword.getText().toString();
if (password.equals(PASSWORD)) {
showSuccessDialog();
if (cbRememberMe.isChecked()) {
SharedPreferences prefs = getSharedPreferences("login_prefs", MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("username", etUsername.getText().toString());
editor.putBoolean("remember_me", true);
editor.apply();
}
} else {
wrongAttempts++;
showRemainingAttempts();
if (wrongAttempts >= MAX_ATTEMPTS) {
btnSignIn.setEnabled(false);
showMaxAttemptsDialog();
}
}
}
private void showRemainingAttempts() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Wrong Password");
builder.setMessage(String.format(
"Incorrect password.\nRemaining attempts: %d",
MAX_ATTEMPTS - wrongAttempts
));
builder.setPositiveButton("OK", null);
builder.show();
}
private void showMaxAttemptsDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Maximum Attempts Reached");
builder.setMessage("You have exceeded the maximum number of login attempts.");
builder.setPositiveButton("OK", null);
builder.show();
}
private void showSuccessDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Login Successful");
builder.setMessage("Welcome!");
builder.setPositiveButton("OK", (dialog, which) -> {
Toast.makeText(MainActivity.this, "Login successful!", Toast.LENGTH_SHORT).show();
});
builder.show();
}
}
activity_main.xml
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/etUsername"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text"
android:hint="Username"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintVertical_bias="0.3"/>
<EditText
android:id="@+id/etPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="textPassword"
android:hint="Password"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@id/etUsername"
android:layout_marginTop="16dp"/>
<CheckBox
android:id="@+id/cbRememberMe"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Remember Me"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@id/etPassword"
android:layout_marginTop="16dp"/>
<Button
android:id="@+id/btnSignIn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Sign In"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="@id/cbRememberMe"
android:layout_marginTop="16dp"/>
</androidx.constraintlayout.widget.ConstraintLayout>
ImplicitIntent
- Sender APP(implicit intent)
package com.example.implicitintent;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity extends AppCompatActivity {
EditText url,text,phone,send;
Button urlBtn,textBtn,phoneBtn,sendBtn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
url=findViewById(R.id.url);
text=findViewById(R.id.text);
phone=findViewById(R.id.phone);
send=findViewById(R.id.send);
urlBtn=findViewById(R.id.urlBtn);
textBtn=findViewById(R.id.textBtn);
phoneBtn=findViewById(R.id.phoneBtn);
sendBtn=findViewById(R.id.sendBtn);
urlBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String urlStr = url.getText().toString();
Intent i = new Intent(Intent.ACTION_VIEW, Uri.parse(urlStr));
startActivity(i);
}
});
textBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String textStr = text.getText().toString();
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("text/plain");
i.putExtra(Intent.EXTRA_TEXT,textStr);
startActivity(Intent.createChooser(i,"send text using"));
}
});
phoneBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String num = phone.getText().toString();
Intent i = new Intent(Intent.ACTION_DIAL);
i.setData(Uri.parse("tel:"+ num));
startActivity(i);
}
});
sendBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String text = send.getText().toString();
Intent i = new Intent(Intent.ACTION_SEND);
i.setType("text/plain");
i.putExtra(Intent.EXTRA_TEXT, text);
startActivity(Intent.createChooser(i, "Send using"));
}
});
}
}
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/textView2"
android:layout_width="72dp"
android:layout_height="28dp"
android:text="websiteUrl"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.054" />
<EditText
android:id="@+id/url"
android:layout_width="187dp"
android:layout_height="40dp"
android:ems="10"
android:hint="www.google.com"
android:inputType="text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.358"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.055" />
<Button
android:id="@+id/urlBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Open Website"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.055" />
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Text To send"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.182" />
<EditText
android:id="@+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="hello "
android:inputType="text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.398"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.189" />
<Button
android:id="@+id/textBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="send Text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.19" />
<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Phone Number"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.352" />
<EditText
android:id="@+id/phone"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Enter Phone Number"
android:inputType="text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.497"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.365" />
<Button
android:id="@+id/phoneBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Dial Num"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.367" />
<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="enter a text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.005"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="@+id/sendBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="send"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.959"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.499" />
<EditText
android:id="@+id/send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="enter a text here it will be show in the another activity"
android:inputType="text"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
and its xml in mainfest
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
- Reciever App
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="@+id/revTv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.receiver;
import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity extends AppCompatActivity {
TextView revTv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
revTv=findViewById(R.id.revTv);
String message = getIntent().getStringExtra(Intent.EXTRA_TEXT);
if(message!=null){
revTv.setText(message);
}
}
}
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<intent-filter>
<action android:name="android.intent.action.SEND"/>
<category android:name="android.intent.category.DEFAULT"/>
<data android:mimeType="text/plain"/>
</intent-filter>
</activity>
Explicit Intent:
MainActivity1
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text"
android:text="Name"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.452"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.049" />
<EditText
android:id="@+id/gmail"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text"
android:text="gmail"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.452"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.161" />
<RadioGroup
android:id="@+id/gender"
android:layout_width="325dp"
android:layout_height="65dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.372">
<RadioButton
android:id="@+id/male"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="male" />
<RadioButton
android:id="@+id/female"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="female" />
</RadioGroup>
<CheckBox
android:id="@+id/english"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="English"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.136"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.553" />
<CheckBox
android:id="@+id/hindi"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="hindi"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.561"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.553" />
<Spinner
android:id="@+id/spinner"
android:layout_width="409dp"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.66" />
<RatingBar
android:id="@+id/ratingBar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.497"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.762" />
<SeekBar
android:id="@+id/seekBar"
android:layout_width="274dp"
android:layout_height="30dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.854" />
<Button
android:id="@+id/submit"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="submit"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.96" />
</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.explicitintent;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.RatingBar;
import android.widget.SeekBar;
import android.widget.Spinner;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity extends AppCompatActivity {
EditText name, email;
RadioGroup genderGroup;
CheckBox english, hindi;
Spinner spinner;
RatingBar ratingBar;
SeekBar seekBar;
Button submit;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
name=findViewById(R.id.name);
email=findViewById(R.id.gmail);
genderGroup=findViewById(R.id.gender);
english=findViewById(R.id.english);
hindi=findViewById(R.id.hindi);
spinner = findViewById(R.id.spinner);
ratingBar = findViewById(R.id.ratingBar);
seekBar = findViewById(R.id.seekBar);
submit = findViewById(R.id.submit);
String langs[]={"java","Python","C++","C"};
ArrayAdapter aa = new ArrayAdapter(this, android.R.layout.simple_list_item_1, langs);
spinner.setAdapter(aa);
submit.setOnClickListener(v->{
String n = name.getText().toString();
String e = email.getText().toString();
int id = genderGroup.getCheckedRadioButtonId();
RadioButton rb = findViewById(id);
String gender = rb.getText().toString();
String langKnown="";
if(english.isChecked()) langKnown+="English";
if(hindi.isChecked()) langKnown+="Hindi";
String prog = spinner.getSelectedItem().toString();
float rating = ratingBar.getRating();
int conf = seekBar.getProgress();
Intent i = new Intent(MainActivity.this, MainActivity2.class);
i.putExtra("name", n);
i.putExtra("email", e);
i.putExtra("gender", gender);
i.putExtra("klang", langKnown);
i.putExtra("prog", prog);
i.putExtra("rating", rating);
i.putExtra("conf", conf);
startActivity(i);
});
}
}
MainActivity2.java
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity2">
<TextView
android:id="@+id/out"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView"
tools:layout_editor_absoluteY="5dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.explicitintent;
import android.os.Bundle;
import android.widget.TextView;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity2 extends AppCompatActivity {
TextView out;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
out = findViewById(R.id.out);
String result =
"Name: " + getIntent().getStringExtra("name") +
"\nEmail: " + getIntent().getStringExtra("email") +
"\nGender: " + getIntent().getStringExtra("gender") +
"\nLanguages Known: " + getIntent().getStringExtra("klang") +
"\nProgramming Language: " + getIntent().getStringExtra("prog") +
"\nRating: " + getIntent().getFloatExtra("rating",0) +
"\nConfidence: " + getIntent().getIntExtra("conf",0);
out.setText(result);
}
}
Calculator Java
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/num1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text"
android:text="Enter num 1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.557"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.04" />
<EditText
android:id="@+id/num2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:inputType="text"
android:text="enter num 2 "
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.557"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.151" />
<TextView
android:id="@+id/result"
android:layout_width="310dp"
android:layout_height="37dp"
android:text="the result will appear here"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.292" />
<Button
android:id="@+id/addBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="add"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.348"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.499" />
<Button
android:id="@+id/subBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="sub"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.7"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.499" />
<Button
android:id="@+id/mulBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="mul"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.348"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.612" />
<Button
android:id="@+id/divBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="div"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.722"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.612" />
</androidx.constraintlayout.widget.ConstraintLayout>
package com.example.calculator;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity extends AppCompatActivity {
EditText num1 , num2;
TextView result;
Button addBtn,subBtn,divBtn,mulBtn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
num1 = findViewById(R.id.num1);
num2 = findViewById(R.id.num2);
result=findViewById(R.id.result);
addBtn =findViewById(R.id.addBtn);
subBtn =findViewById(R.id.subBtn);
mulBtn =findViewById(R.id.mulBtn);
divBtn =findViewById(R.id.divBtn);
addBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
double a = Double.parseDouble((num1.getText().toString()));
double b = Double.parseDouble((num2.getText().toString()));
result.setText("Result: "+(a+b));
}
});
subBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
double a= Double.parseDouble((num1.getText().toString()));
double b= Double.parseDouble((num2.getText().toString()));
result.setText("Result: "+(a-b));
}
});
mulBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
double a= Double.parseDouble((num1.getText().toString()));
double b= Double.parseDouble((num2.getText().toString()));
result.setText("Result: "+ (a*b));
}
});
divBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
double a = Double.parseDouble((num1.getText().toString()));
double b = Double.parseDouble((num2.getText().toString()));
if(b==0){
result.setText("Num cannot divided by 0");
}else{
result.setText("Result: "+(a/b));
}
}
});
}
}
Assignment 2 – Currency Converter
Step 1: Create a new Android Project
- Name:
CurrencyConverter
- Package:
com.alone_x.currencyconverter
- Minimum SDK: API 21 (Lollipop)
- Empty Activity
Step 2: Design activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="16dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Currency Converter"
android:textSize="24sp"
android:textStyle="bold"
android:layout_gravity="center_horizontal"
android:paddingBottom="16dp"/>
<Spinner
android:id="@+id/fromCurrency"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
<Spinner
android:id="@+id/toCurrency"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="8dp"/>
<EditText
android:id="@+id/amountInput"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Enter amount"
android:inputType="numberDecimal"
android:layout_marginTop="8dp"/>
<Button
android:id="@+id/convertBtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Convert"
android:layout_marginTop="8dp"/>
<TextView
android:id="@+id/resultView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Result will appear here"
android:textSize="18sp"
android:paddingTop="16dp"/>
</LinearLayout>
Step 3: Write MainActivity.java
package com.alone_x.currencyconverter;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;
public class MainActivity extends AppCompatActivity {
String[] currencies = {"INR", "USD", "EUR", "JPY", "GBP"};
double[][] conversionRates = {
{1, 0.012, 0.011, 1.75, 0.0095}, // INR to all
{83.3, 1, 0.91, 145.0, 0.79}, // USD to all
{91.4, 1.10, 1, 158.5, 0.87}, // EUR to all
{0.57, 0.0069,0.0063,1, 0.0055},// JPY to all
{105.3, 1.27, 1.15, 181.2, 1} // GBP to all
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EdgeToEdge.enable(this);
setContentView(R.layout.activity_main);
ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main), (v, insets) -> {
Insets systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars());
v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom);
return insets;
});
Spinner fromSpinner = findViewById(R.id.fromCurrency);
Spinner toSpinner = findViewById(R.id.toCurrency);
EditText amountInput = findViewById(R.id.amountInput);
Button convertBtn = findViewById(R.id.convertBtn);
TextView resultView = findViewById(R.id.resultView);
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, currencies);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
fromSpinner.setAdapter(adapter);
toSpinner.setAdapter(adapter);
convertBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String amountStr = amountInput.getText().toString().trim();
if (amountStr.isEmpty()) {
Toast.makeText(MainActivity.this, "Enter an amount", Toast.LENGTH_SHORT).show();
return;
}
double amount = Double.parseDouble(amountStr);
int fromIndex = fromSpinner.getSelectedItemPosition();
int toIndex = toSpinner.getSelectedItemPosition();
double rate = conversionRates[fromIndex][toIndex];
double converted = amount * rate;
resultView.setText(String.format("%.2f %s = %.2f %s",
amount,
currencies[fromIndex],
converted,
currencies[toIndex]));
}
});
}
}
Step 4: Run the app
- Select currencies, enter amount, click Convert
- Result displayed in
TextView
