Practical 24.

1: Write a program to turn on, get visible, list devices and turn off
Bluetooth with the help of following GUI:

JAVA FILE:
package com.example.prac24;

import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

import android.Manifest;
import android.annotation.SuppressLint;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.Set;

public class MainActivity extends AppCompatActivity {

Button b1, b2, b3, b4; // Buttons for Bluetooth control

private BluetoothAdapter BA; // Bluetooth Adapter
private Set<BluetoothDevice> pairedDevices; // Set of paired devices
ListView lv; // ListView to display paired devices

private static final int REQUEST_ENABLE_BT = 1; // Request code for enabling Bluetooth
private static final int REQUEST_BLUETOOTH_PERMISSIONS = 2; // Request code for Bluetooth
permissions

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

// Initialize UI components
 b1 = findViewById(R.id.TurnOn);
b2 = findViewById(R.id.GetVisible);
b3 = findViewById(R.id.ListDevices);
b4 = findViewById(R.id.TurnOff);
lv = findViewById(R.id.pairedDevice1);

// Get the default Bluetooth adapter

BA = BluetoothAdapter.getDefaultAdapter();

// Check if the device supports Bluetooth

if (BA == null) {
Toast.makeText(getApplicationContext(), "Bluetooth not supported on this device",
Toast.LENGTH_LONG).show();
finish();
}

// Request runtime permissions for Android 12+

requestBluetoothPermissions();

// Set button actions

b1.setOnClickListener(this::on);
b2.setOnClickListener(this::visible);
b3.setOnClickListener(this::list);
b4.setOnClickListener(this::off);
}

private void requestBluetoothPermissions() {

if (ContextCompat.checkSelfPermission(this, Manifest.permission.BLUETOOTH_CONNECT)
!= PackageManager.PERMISSION_GRANTED ||
ContextCompat.checkSelfPermission(this, Manifest.permission.BLUETOOTH_SCAN)
!= PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this,
new String[]{Manifest.permission.BLUETOOTH_CONNECT,
Manifest.permission.BLUETOOTH_SCAN},
REQUEST_BLUETOOTH_PERMISSIONS);
}
}

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[]
grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == REQUEST_BLUETOOTH_PERMISSIONS) {
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
{
 Toast.makeText(this, "Bluetooth permissions granted", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Bluetooth permissions denied", Toast.LENGTH_SHORT).show();
finish();
}
}
}

@SuppressLint("MissingPermission")
public void on(View v) {
if (BA.isEnabled()) {
Toast.makeText(this, "Bluetooth is already on", Toast.LENGTH_SHORT).show();
} else {
Intent turnOnIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(turnOnIntent, REQUEST_ENABLE_BT);
Toast.makeText(this, "Bluetooth is now turned on", Toast.LENGTH_SHORT).show();
}
}

@SuppressLint("MissingPermission")
public void off(View v) {
if (BA.isEnabled()) {
BA.disable();
Toast.makeText(this, "Bluetooth is now turned off", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Bluetooth is already off", Toast.LENGTH_SHORT).show();
}
}

@SuppressLint("MissingPermission")
public void visible(View v) {
Intent visibleIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
visibleIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(visibleIntent);
Toast.makeText(this, "Device is now discoverable for 5 minutes",
Toast.LENGTH_SHORT).show();
}

@SuppressLint("MissingPermission")
public void list(View v) {
pairedDevices = BA.getBondedDevices();

ArrayList<String> deviceList = new ArrayList<>();

for (BluetoothDevice device : pairedDevices) {
deviceList.add(device.getName() + " - " + device.getAddress());
 }

if (!deviceList.isEmpty()) {
ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
android.R.layout.simple_list_item_1, deviceList);
lv.setAdapter(adapter);
} else {
Toast.makeText(this, "No paired devices found", Toast.LENGTH_SHORT).show();
}
}
}

activity file:

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
android:background="#FFFFFF">

<!-- Title TextView -->

<TextView
android:id="@+id/textview1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="Bluetooth Control Panel"
android:textColor="#0D0B0B"
android:textSize="24sp"
android:textStyle="bold"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />

<!-- Turn On Button -->

<Button
android:id="@+id/TurnOn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/textview1"
android:layout_marginTop="16dp"
android:layout_centerHorizontal="true"
android:backgroundTint="#809CC7"
android:text="Turn On"
android:textStyle="bold" />
<!-- Get Visible Button -->
<Button
android:id="@+id/GetVisible"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/TurnOn"
android:layout_marginTop="16dp"
android:layout_centerHorizontal="true"
android:backgroundTint="#626DC5"
android:text="Get Visible"
android:textStyle="bold" />

<!-- List Devices Button -->

<Button
android:id="@+id/ListDevices"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/GetVisible"
android:layout_marginTop="16dp"
android:layout_centerHorizontal="true"
android:backgroundTint="#24338A"
android:text="List Devices"
android:textStyle="bold" />

<!-- Turn Off Button -->

<Button
android:id="@+id/TurnOff"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/ListDevices"
android:layout_marginTop="16dp"
android:layout_centerHorizontal="true"
android:backgroundTint="#111157"
android:text="Turn Off"
android:textStyle="bold" />

<!-- Paired Devices Label -->

<TextView
android:id="@+id/paired"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/TurnOff"
android:layout_marginTop="24dp"
android:layout_marginBottom="8dp"
 android:layout_centerHorizontal="true"
android:text="Paired Devices:"
android:textColor="#02040D"
android:textSize="18sp"
android:textStyle="bold" />

<!-- Paired Devices List -->

<ListView
android:id="@+id/pairedDevice1"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_below="@id/paired"
android:layout_marginTop="8dp"
android:layout_marginHorizontal="16dp"
android:divider="#CCCCCC"
android:dividerHeight="1dp" />
</RelativeLayout>

Manifest File:

<manifest
xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.prac24">

<!-- Bluetooth Permissions -->

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
<uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
<uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />

<!-- Location Permissions for Bluetooth Scanning -->

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/Theme.Prac24">

<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>

Output: