Practical 17 — Create a student record system with the following fields: Roll number, Name, Age, Email, and Contact number. Use the Volley library to retrieve the records from the server (Use Json Array request)
Gradle dependency (add to app/build.gradle)
dependencies {
implementation 'com.android.volley:volley:1.2.1'
implementation 'androidx.appcompat:appcompat:1.7.1'
implementation 'com.google.android.material:material:1.13.0'
implementation 'androidx.constraintlayout:constraintlayout:2.2.1'
// other dependencies...
}
AndroidManifest.xml (ensure INTERNET permission)
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.volley">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:label="@string/app_name"
android:theme="@style/Theme.Volley">
<activity android:name=".MainActivity" android:exported="true">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MainActivity.java
package com.example.volley;
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.StringRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class MainActivity extends AppCompatActivity {
Button btnString, btnJson;
TextView txtdata;
// example endpoints from your practical
String links = "https://www.w3schools.com/xml/note.xml";
String Jsonlinks = "https://mocki.io/v1/7d6d5cdb-04bf-4df6-8e0c-5e0a70069eb4";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtdata = findViewById(R.id.textView);
btnString = findViewById(R.id.btnString);
btnJson = findViewById(R.id.btnJson);
RequestQueue queue = Volley.newRequestQueue(getApplicationContext());
btnString.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
StringRequest stringRequest = new StringRequest(Request.Method.GET, links,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
txtdata.setText(response);
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
txtdata.setText("Error: " + error.getMessage());
}
});
queue.add(stringRequest);
}
});
btnJson.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(Request.Method.GET,
Jsonlinks, null,
new Response.Listener<JSONArray>() {
@Override
public void onResponse(JSONArray response) {
StringBuilder buffer = new StringBuilder();
for (int i = 0; i < response.length(); i++) {
try {
JSONObject obj = response.getJSONObject(i);
buffer.append("Roll no.: ").append(obj.getInt("roll")).append("\n")
.append("Name: ").append(obj.getString("name")).append("\n")
.append("Email: ").append(obj.optString("email", "N/A")).append("\n\n");
} catch (JSONException e) {
e.printStackTrace();
}
}
txtdata.setText(buffer.toString());
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
txtdata.setText("Error: " + error.getMessage());
}
}
);
queue.add(jsonArrayRequest);
}
});
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:padding="20dp"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<Button
android:id="@+id/btnString"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fetch XML String" />
<Button
android:id="@+id/btnJson"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fetch JSON Array"
android:layout_marginTop="12dp" />
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fetched data will appear here"
android:padding="12dp"
android:textSize="16sp"
android:layout_marginTop="16dp"/>
</LinearLayout>
</ScrollView>
Practical 18 - Create a student record system with the following fields: Roll number, Name, Age, Email, and Contact number. Use the OkHttp library to retrieve the records from the server.
app → manifests → AndroidManifest.xml
Add THIS line before < application >:
<uses-permission android:name="android.permission.INTERNET"/>
app/build.gradle.kts
Inside dependencies add:
implementation("com.squareup.okhttp3:okhttp:4.12.0")
res → layout → activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:padding="20dp"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/btnString"
android:text="Fetch XML"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<Button
android:id="@+id/btnJson"
android:text="Fetch JSON"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="12dp" />
<TextView
android:id="@+id/textView"
android:text=""
android:textSize="16sp"
android:padding="16dp"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>
java/com.example.okhttp/MainActivity.java
package com.example.practical18;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
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;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
public class MainActivity extends AppCompatActivity {
private static final String TAG = "OKHTTP_RAW";
Button btnString, btnJson;
TextView txtdata;
// XML example (works)
String links = "https://www.w3schools.com/xml/note.xml";
// Try this stable JSON array endpoint for testing:
// It returns a JSON array of users.
// If this works, your app is fine and the problem is your mock URL.
String Jsonlinks = "https://jsonplaceholder.typicode.com/users";
OkHttpClient client;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtdata = findViewById(R.id.textView);
btnString = findViewById(R.id.btnString);
btnJson = findViewById(R.id.btnJson);
client = new OkHttpClient();
// Fetch XML String Output
btnString.setOnClickListener(v -> {
Request req = new Request.Builder().url(links).build();
client.newCall(req).enqueue(new Callback() {
@Override
public void onFailure(@NonNull Call call, @NonNull IOException e) {
Log.e(TAG, "XML request failed", e);
runOnUiThread(() -> txtdata.setText("XML request failed: " + e.getMessage()));
}
@Override
public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
String data = response.body() != null ? response.body().string() : "";
Log.d(TAG, "XML response code=" + response.code() + " body=" + data);
runOnUiThread(() -> txtdata.setText(data));
}
});
});
// Fetch JSON Student Records (robust handling)
btnJson.setOnClickListener(v -> {
Request jsonReq = new Request.Builder().url(Jsonlinks).build();
client.newCall(jsonReq).enqueue(new Callback() {
@Override
public void onFailure(@NonNull Call call, @NonNull IOException e) {
Log.e(TAG, "JSON request failed", e);
runOnUiThread(() -> txtdata.setText("JSON request failed: " + e.getMessage()));
}
@Override
public void onResponse(@NonNull Call call, @NonNull Response response) throws IOException {
String body = response.body() != null ? response.body().string() : "";
String contentType = response.header("Content-Type", "unknown");
Log.d(TAG, "code=" + response.code() + " contentType=" + contentType + " body=" + body);
// Show raw body first so you can see what's returned
runOnUiThread(() -> txtdata.setText(body));
if (!response.isSuccessful()) {
runOnUiThread(() -> txtdata.setText("Server error: " + response.code()));
return;
}
String trimmed = body.trim();
if (trimmed.isEmpty()) {
runOnUiThread(() -> txtdata.setText("Empty response"));
return;
}
// If the server returned HTML (starts with <), show helpful message
if (trimmed.startsWith("<")) {
runOnUiThread(() -> txtdata.setText("Expected JSON but got HTML/markup. Open the URL in browser to inspect.\n\nFirst 200 chars:\n" + trimmed.substring(0, Math.min(200, trimmed.length()))));
return;
}
// Now try to parse JSON (array or object)
try {
StringBuilder buffer = new StringBuilder();
if (trimmed.startsWith("[")) {
// JSON array
JSONArray jsonArray = new JSONArray(trimmed);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject studentObj = jsonArray.getJSONObject(i);
// Use optX to avoid exceptions if keys missing
buffer.append("Roll/ID: ").append(studentObj.optInt("id")).append("\n")
.append("Name: ").append(studentObj.optString("name")).append("\n")
.append("Email: ").append(studentObj.optString("email")).append("\n\n");
}
} else if (trimmed.startsWith("{")) {
// JSON object: maybe { "students": [...] } or a single object
JSONObject jsonObject = new JSONObject(trimmed);
if (jsonObject.has("students")) {
JSONArray arr = jsonObject.getJSONArray("students");
for (int i = 0; i < arr.length(); i++) {
JSONObject studentObj = arr.getJSONObject(i);
buffer.append("Roll no.: ").append(studentObj.optInt("roll")).append("\n")
.append("Name: ").append(studentObj.optString("name")).append("\n")
.append("Email: ").append(studentObj.optString("email")).append("\n\n");
}
} else if (jsonObject.has("data") && jsonObject.get("data") instanceof JSONArray) {
JSONArray arr = jsonObject.getJSONArray("data");
for (int i = 0; i < arr.length(); i++) {
JSONObject studentObj = arr.getJSONObject(i);
buffer.append("Roll no.: ").append(studentObj.optInt("roll")).append("\n")
.append("Name: ").append(studentObj.optString("name")).append("\n")
.append("Email: ").append(studentObj.optString("email")).append("\n\n");
}
} else {
// treat jsonObject as a single student-like object
buffer.append("Roll no.: ").append(jsonObject.optInt("roll")).append("\n")
.append("Name: ").append(jsonObject.optString("name")).append("\n")
.append("Email: ").append(jsonObject.optString("email")).append("\n\n");
}
} else {
runOnUiThread(() -> txtdata.setText("Response is not JSON/HTML. First chars: " + trimmed.substring(0, Math.min(100, trimmed.length()))));
return;
}
final String out = buffer.toString();
runOnUiThread(() -> {
if (out.isEmpty()) {
txtdata.setText("Parsed JSON but no recognizable fields found. Raw:\n" + trimmed);
} else {
txtdata.setText(out);
}
});
} catch (JSONException e) {
Log.e(TAG, "JSON parse error", e);
runOnUiThread(() -> txtdata.setText("JSON parse error: " + e.getMessage() + "\n\nRaw response:\n" + (trimmed.length() > 200 ? trimmed.substring(0, 200) : trimmed)));
}
}
});
});
}
}
Practical 19: Create a Json record system with the following fields: Id, User id, Title, Body. Use the Retrofit library to retrieve the records from the server.
Open app/src/main/AndroidManifest.xml and add above :
<uses-permission android:name="android.permission.INTERNET"/>
Open app/build.gradle (module) and inside dependencies {} add:
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:padding="16dp"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/btnfetch"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Fetch Posts" />
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="12dp">
<TextView
android:id="@+id/txtview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="14sp"
android:padding="8dp" />
</ScrollView>
</LinearLayout>
model.java
package com.example.myapplication;
public class model {
private int userId;
private int id;
private String title;
private String body;
public int getUserId() { return userId; }
public void setUserId(int userId) { this.userId = userId; }
public int getId() { return id; }
public void setId(int id) { this.id = id; }
public String getTitle() { return title; }
public void setTitle(String title) { this.title = title; }
public String getBody() { return body; }
public void setBody(String body) { this.body = body; }
}
myapi.java
package com.example.myapplication;
import java.util.List;
import retrofit2.Call;
import retrofit2.http.GET;
public interface myapi {
@GET("posts")
Call<List<model>> getmodels();
}
MainActivity.java
package com.example.myapplication;
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 txtview;
Button btnfetch;
String baseUrl = "https://jsonplaceholder.typicode.com/";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtview = findViewById(R.id.txtview);
btnfetch = findViewById(R.id.btnfetch);
btnfetch.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
txtview.setText(""); // clear previous output
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(baseUrl)
.addConverterFactory(GsonConverterFactory.create())
.build();
myapi api = retrofit.create(myapi.class);
Call<List<model>> call = api.getmodels();
call.enqueue(new Callback<List<model>>() {
@Override
public void onResponse(Call<List<model>> call, Response<List<model>> response) {
if (!response.isSuccessful()) {
txtview.setText("Server returned: " + response.code());
return;
}
List<model> data = response.body();
if (data == null) {
txtview.setText("Response body is null");
return;
}
StringBuilder sb = new StringBuilder();
for (model m : data) {
sb.append("id: ").append(m.getId()).append("\n");
sb.append("user_id: ").append(m.getUserId()).append("\n");
sb.append("Title: ").append(m.getTitle()).append("\n");
sb.append("Body: ").append(m.getBody()).append("\n\n");
}
txtview.setText(sb.toString());
}
@Override
public void onFailure(Call<List<model>> call, Throwable t) {
txtview.setText("Request failed: " + t.getMessage());
Toast.makeText(MainActivity.this, "Network error", Toast.LENGTH_SHORT).show();
}
});
}
});
}
}
Practical 20: Create Flutter application to demonstrate BMI calculator
New Project → Flutter → Project name bmi_app.
Project structure
bmi_app/
├─ lib/
│ ├─ main.dart
│ └─ BMICalculator.dart <-- your widget
├─ pubspec.yaml
└─ android/ ios/ (platform folders)
BMICalculator.dart
// lib/BMICalculator.dart
import 'package:flutter/material.dart';
class BMICalculator extends StatefulWidget {
const BMICalculator({super.key});
@override
State<BMICalculator> createState() => _BMICalculatorState();
}
class _BMICalculatorState extends State<BMICalculator> {
final TextEditingController heightController = TextEditingController();
final TextEditingController weightController = TextEditingController();
double bmiResult = 0.0;
void calculateBMI() {
setState(() {
try {
final double height = double.parse(heightController.text);
final double weight = double.parse(weightController.text);
if (height <= 0 || weight <= 0) {
throw Exception('Height and weight must be positive numbers');
}
bmiResult = weight / (height * height);
} catch (e) {
bmiResult = 0.0;
}
});
}
String _getCategory(double bmi) {
if (bmi < 18.5) return 'Underweight 😲';
if (bmi <= 24.9) return 'Normal Weight 😉';
if (bmi <= 29.9) return 'Overweight 🤒';
return 'Obese 💀';
}
void clearResult() {
setState(() {
heightController.clear();
weightController.clear();
bmiResult = 0.0;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
backgroundColor: Colors.green,
title: const Text(
'BMI Calculator',
style: TextStyle(color: Colors.white),
),
),
body: Center(
child: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
TextField(
controller: heightController,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
labelText: 'Height (m)',
border: OutlineInputBorder(),
),
),
const SizedBox(height: 20),
TextField(
controller: weightController,
keyboardType: TextInputType.number,
decoration: const InputDecoration(
labelText: 'Weight (kg)',
border: OutlineInputBorder(),
),
),
const SizedBox(height: 30),
ElevatedButton(
onPressed: calculateBMI,
child: const Text('Calculate BMI'),
),
const SizedBox(height: 12),
ElevatedButton(
onPressed: clearResult,
child: const Text('Clear'),
),
const SizedBox(height: 30),
bmiResult > 0
? Container(
width: double.infinity,
padding: const EdgeInsets.all(20),
decoration: BoxDecoration(
color: Colors.greenAccent,
borderRadius: BorderRadius.circular(10),
),
child: Column(
children: [
Text(
'BMI: ${bmiResult.toStringAsFixed(1)}',
style: const TextStyle(
fontSize: 24,
fontWeight: FontWeight.bold,
),
),
Text(
'You are ${_getCategory(bmiResult)}',
style: const TextStyle(fontSize: 20),
),
],
),
)
: const SizedBox.shrink(),
],
),
),
),
);
}
}
main.dart
import 'package:flutter/material.dart';
import 'BMICalculator.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
title: 'BMI App',
theme: ThemeData(
primarySwatch: Colors.green,
),
home: const BMICalculator(),
);
}
}
Start an emulator (AVD) or connect device.
In terminal:
flutter run
Practical 21 — Registration Form (Flutter)
Project Structure
registration_form/
│
├── lib/
│ ├── main.dart
│ ├── RegistrationForm.dart
│ └── DetailsPage.dart
│
├── pubspec.yaml
│
├── android/ (Auto generated)
├── ios/ (Auto generated)
├── test/
└── build/
lib/main.dart
import 'package:flutter/material.dart';
import 'RegistrationForm.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: const RegistrationForm(),
);
}
}
import 'package:flutter/material.dart';
import 'DetailsPage.dart';
class RegistrationForm extends StatefulWidget {
const RegistrationForm({super.key});
@override
State<RegistrationForm> createState() => _RegistrationFormState();
}
class _RegistrationFormState extends State<RegistrationForm> {
final TextEditingController nameController = TextEditingController();
String? gender;
bool langEnglish = false;
bool langHindi = false;
bool langMarathi = false;
final List<String> cities = ["Mumbai", "Delhi", "Pune"];
String? selectedCity;
bool darkBackground = false;
void onSubmit() {
List<String> langList = [];
if (langEnglish) langList.add("English");
if (langHindi) langList.add("Hindi");
if (langMarathi) langList.add("Marathi");
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => Details(
name: nameController.text,
gender: gender ?? "Not selected",
languages: langList,
selectedCity: selectedCity,
),
),
);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("Registration Form"), backgroundColor: Colors.green),
body: Container(
color: darkBackground ? Colors.green[50] : Colors.white,
child: Padding(
padding: const EdgeInsets.all(16.0),
child: SingleChildScrollView(
child: Column(
crossAxisAlignment: CrossAxisAlignment.stretch,
children: [
TextField(
controller: nameController,
decoration: const InputDecoration(
labelText: "Enter name:",
border: OutlineInputBorder(),
),
),
const SizedBox(height: 16),
const Text("Select your gender:"),
RadioListTile(
title: const Text("Male"),
value: "Male",
groupValue: gender,
onChanged: (value) => setState(() => gender = value),
),
RadioListTile(
title: const Text("Female"),
value: "Female",
groupValue: gender,
onChanged: (value) => setState(() => gender = value),
),
const SizedBox(height: 16),
const Text("Select the languages:"),
CheckboxListTile(
title: const Text("English"),
value: langEnglish,
onChanged: (val) => setState(() => langEnglish = val ?? false),
),
CheckboxListTile(
title: const Text("Hindi"),
value: langHindi,
onChanged: (val) => setState(() => langHindi = val ?? false),
),
CheckboxListTile(
title: const Text("Marathi"),
value: langMarathi,
onChanged: (val) => setState(() => langMarathi = val ?? false),
),
const SizedBox(height: 16),
DropdownButton(
isExpanded: true,
value: selectedCity,
hint: const Text("Select city"),
items: cities.map((e) => DropdownMenuItem(value: e, child: Text(e))).toList(),
onChanged: (value) => setState(() => selectedCity = value),
),
SwitchListTile(
title: const Text("Dark Background"),
value: darkBackground,
onChanged: (val) => setState(() => darkBackground = val),
),
const SizedBox(height: 24),
ElevatedButton(onPressed: onSubmit, child: const Text("Submit")),
],
),
),
),
),
);
}
}
lib/DetailsPage.dart
import 'package:flutter/material.dart';
class Details extends StatelessWidget {
final String name;
final String gender;
final List<String> languages;
final String? selectedCity;
const Details({
super.key,
required this.name,
required this.gender,
required this.languages,
required this.selectedCity,
});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("Details"), backgroundColor: Colors.blue),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text("Name: $name"),
Text("Gender: $gender"),
Text("Languages: ${languages.isEmpty ? "None" : languages.join(", ")}"),
Text("City: ${selectedCity ?? "Not selected"}"),
],
),
),
);
}
}
lib/DetailsPage.dart
import 'package:flutter/material.dart';
class Details extends StatelessWidget {
final String name;
final String gender;
final List<String> languages;
final String? selectedCity;
const Details({
super.key,
required this.name,
required this.gender,
required this.languages,
required this.selectedCity,
});
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("Details"), backgroundColor: Colors.blue),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
Text("Name: $name"),
Text("Gender: $gender"),
Text("Languages: ${languages.isEmpty ? "None" : languages.join(", ")}"),
Text("City: ${selectedCity ?? "Not selected"}"),
],
),
),
);
}
}
PRACTICAL 22 — SQLite CRUD (Flutter + Sqflite)
PROJECT STRUCTURE
sqflite_crud/
│
├── lib/
│ ├── main.dart
│ ├── Homepage.dart
│ └── database_helper.dart
│
├── pubspec.yaml
│
├── android/
├── ios/
└── build/
pubspec.yaml (dependencies section)
dependencies:
flutter:
sdk: flutter
cupertino_icons: ^1.0.8
sqflite: ^2.2.0
path_provider: ^2.0.15
path: ^1.8.3
lib/main.dart
import 'package:flutter/material.dart';
import 'Homepage.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return MaterialApp(
debugShowCheckedModeBanner: false,
home: const MyHomePage(),
);
}
}
lib/database_helper.dart
import 'dart:async';
import 'dart:io';
import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:sqflite/sqflite.dart';
class DatabaseHelper {
static const _databaseName = "MyDatabase.db";
static const _databaseVersion = 1;
static const table = 'my_table';
static const columnId = '_id';
static const columnName = 'name';
DatabaseHelper._privateConstructor();
static final DatabaseHelper instance = DatabaseHelper._privateConstructor();
static Database? _database;
Future<Database> get database async {
_database ??= await _initDatabase();
return _database!;
}
Future<Database> _initDatabase() async {
Directory documentsDirectory = await getApplicationDocumentsDirectory();
String path = join(documentsDirectory.path, _databaseName);
return await openDatabase(path,
version: _databaseVersion, onCreate: _onCreate);
}
Future _onCreate(Database db, int version) async {
await db.execute('''
CREATE TABLE $table (
$columnId INTEGER PRIMARY KEY,
$columnName TEXT NOT NULL
)
''');
}
Future<int> insert(Map<String, dynamic> row) async {
Database db = await database;
return await db.insert(table, row);
}
Future<List<Map<String, dynamic>>> queryAllRows() async {
Database db = await database;
return await db.query(table);
}
Future<int> update(Map<String, dynamic> row) async {
Database db = await database;
int id = row[columnId];
return await db.update(table, row, where: '$columnId = ?', whereArgs: [id]);
}
Future<int> delete(int id) async {
Database db = await database;
return await db.delete(table, where: '$columnId = ?', whereArgs: [id]);
}
}
lib/Homepage.dart
import 'package:flutter/material.dart';
import 'database_helper.dart';
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key});
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
final _idController = TextEditingController();
final _nameController = TextEditingController();
String _message = "";
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('SQLite Demo')),
body: Padding(
padding: const EdgeInsets.all(16.0),
child: Column(
children: [
TextField(controller: _idController, decoration: const InputDecoration(labelText: "ID")),
TextField(controller: _nameController, decoration: const InputDecoration(labelText: "Name")),
const SizedBox(height: 20),
ElevatedButton(
onPressed: () async {
final id = int.tryParse(_idController.text.trim());
final name = _nameController.text.trim();
if (id == null || name.isEmpty) {
setState(() => _message = "Enter valid ID & Name");
return;
}
await DatabaseHelper.instance.insert({
DatabaseHelper.columnId: id,
DatabaseHelper.columnName: name,
});
_idController.clear();
_nameController.clear();
setState(() => _message = "Inserted Successfully");
},
child: const Text("Insert"),
),
ElevatedButton(
onPressed: () async {
final rows = await DatabaseHelper.instance.queryAllRows();
setState(() => _message = rows.toString());
},
child: const Text("Show"),
),
ElevatedButton(
onPressed: () async {
final id = int.tryParse(_idController.text.trim());
final name = _nameController.text.trim();
if (id == null || name.isEmpty) {
setState(() => _message = "Enter valid ID & Name");
return;
}
await DatabaseHelper.instance.update({
DatabaseHelper.columnId: id,
DatabaseHelper.columnName: name,
});
setState(() => _message = "Updated Successfully");
},
child: const Text("Update"),
),
ElevatedButton(
onPressed: () async {
final id = int.tryParse(_idController.text.trim());
if (id == null) {
setState(() => _message = "Enter valid ID");
return;
}
await DatabaseHelper.instance.delete(id);
setState(() => _message = "Deleted Successfully");
},
child: const Text("Delete"),
),
const SizedBox(height: 20),
Text(_message, style: const TextStyle(fontSize: 16)),
],
),
),
);
}
}
PRACTICAL 23 — REST API (Flutter + HTTP GET)
PROJECT STRUCTURE
rest_api_app/
│
├── lib/
│ ├── main.dart
│ ├── HomePage.dart
│ ├── User.dart
│ └── Remote_service.dart
│
├── pubspec.yaml
├── android/
├── ios/
└── build/
pubspec.yaml (dependencies)
dependencies:
flutter:
sdk: flutter
http: ^0.13.6
lib/main.dart
import 'package:flutter/material.dart';
import 'HomePage.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({super.key});
@override
Widget build(BuildContext context) {
return const MaterialApp(
debugShowCheckedModeBanner: false,
home: MyHomePage(),
);
}
}
lib/User.dart
import 'dart:convert';
List<User> userFromJson(String str) =>
List<User>.from(json.decode(str).map((x) => User.fromJson(x)));
class User {
int rno;
String name;
User({required this.rno, required this.name});
factory User.fromJson(Map<String, dynamic> json) {
return User(
rno: json["rno"],
name: json["name"],
);
}
}
lib/User.dart
import 'dart:convert';
List<User> userFromJson(String str) =>
List<User>.from(json.decode(str).map((x) => User.fromJson(x)));
class User {
int rno;
String name;
User({required this.rno, required this.name});
factory User.fromJson(Map<String, dynamic> json) {
return User(
rno: json["rno"],
name: json["name"],
);
}
}
lib/Remote_service.dart
import 'package:http/http.dart' as http;
import 'User.dart';
class RemoteService {
Future<List<User>> getUsers() async {
final uri = Uri.parse("https://mocki.io/v1/5e56d735-4e27-4afa-b82a-a4c384c42523");
final response = await http.get(uri);
if (response.statusCode == 200) {
return userFromJson(response.body);
} else {
return []; // handle safely
}
}
}
lib/HomePage.dart
import 'package:flutter/material.dart';
import 'User.dart';
import 'Remote_service.dart';
class MyHomePage extends StatefulWidget {
const MyHomePage({super.key});
@override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
List<User>? users;
bool isLoaded = false;
@override
void initState() {
super.initState();
fetchData();
}
fetchData() async {
users = await RemoteService().getUsers();
setState(() {
isLoaded = true;
});
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text("REST API Demo")),
body: isLoaded
? (users == null || users!.isEmpty
? const Center(child: Text("No data found"))
: ListView.builder(
itemCount: users!.length,
itemBuilder: (context, index) {
return ListTile(
title: Text(users![index].name),
subtitle: Text("Rno: ${users![index].rno}"),
);
}))
: const Center(child: CircularProgressIndicator()),
);
}
}
