Practical no 24 : android:layout_height="wrap_content"

droid:text="Turn Off"
Name:-Roshan kumar
droid:layout_below="@id/btn_list_devices"
<?xml version="1.0" encoding="utf-8"?> android:layout_centerHorizontal="true"
<RelativeLayout android:layout_marginTop="20dp" />
xmlns:android="http://schemas.android.com/apk/res/
android" <!-- Output TextView to show List of Devices -->
android:layout_width="match_parent" <TextView
android:layout_height="match_parent"> android:id="@+id/tv_output"
android:layout_width="wrap_content"
<!--Bluetooth Image --> android:layout_height="wrap_content"
<ImageView android:text=""
android:id="@+id/bluetooth_image" android:layout_below="@id/btn_turn_off"
android:layout_width="150dp" android:layout_marginTop="20dp"
android:layout_height="150dp" android:layout_centerHorizontal="true" />
android:src="@drawable/blutooth" </RelativeLayout>
android:layout_centerHorizontal="true"
Mainactivity.java file:
android:layout_marginTop="50dp" />
package com.example.hello;
<!-- Turn On Button -->
<Button import android.bluetooth.BluetoothAdapter;
android:id="@+id/btn_turn_on" import android.bluetooth.BluetoothDevice;
android:layout_width="wrap_content" import android.content.Intent;
android:layout_height="wrap_content" import android.content.pm.PackageManager;
android:text="Turn On" import android.os.Bundle;
android:layout_below="@id/bluetooth_image" import android.widget.Button;
android:layout_centerHorizontal="true" import android.widget.TextView;
android:layout_marginTop="20dp" /> import android.widget.Toast;

<!-- Get Visible Button --> import androidx.appcompat.app.AppCompatActivity;

<Button import androidx.core.app.ActivityCompat;
android:id="@+id/btn_get_visible"
android:layout_width="wrap_content" import java.util.Set;
android:layout_height="wrap_content"
android:text="Get Visible" public class practical_no_24 extends
android:layout_below="@id/btn_turn_on" AppCompatActivity {
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp" /> BluetoothAdapter bluetoothAdapter;
TextView tvOutput;
<!-- List Devices Button --> Button btnTurnOn, btnGetVisible, btnListDevices,
<Button btnTurnOff;
android:id="@+id/btn_list_devices"
android:layout_width="wrap_content" @Override
android:layout_height="wrap_content" protected void onCreate(Bundle
android:text="List Devices" savedInstanceState) {
android:layout_below="@id/btn_get_visible" super.onCreate(savedInstanceState);
android:layout_centerHorizontal="true"
android:layout_marginTop="20dp" /> setContentView(R.layout.activity_practical_no24);

<!-- Turn Off Button --> bluetoothAdapter =

<Button BluetoothAdapter.getDefaultAdapter();
android:id="@+id/btn_turn_off" tvOutput = findViewById(R.id.tv_output);
android:layout_width="wrap_content" btnTurnOn = findViewById(R.id.btn_turn_on);
 btnGetVisible = discoverableIntent.putExtra(BluetoothAdapter.EXTRA_
findViewById(R.id.btn_get_visible); DISCOVERABLE_DURATION, 300);
btnListDevices = startActivity(discoverableIntent);
findViewById(R.id.btn_list_devices); } else {
btnTurnOff = findViewById(R.id.btn_turn_off); Toast.makeText(this, "Please turn on Bluetooth
first", Toast.LENGTH_SHORT).show();
// Button click listeners }
btnTurnOn.setOnClickListener(v -> }
turnOnBluetooth());
btnGetVisible.setOnClickListener(v -> // List paired devices
makeBluetoothVisible()); private void listPairedDevices() {
btnListDevices.setOnClickListener(v -> if (bluetoothAdapter.isEnabled()) {
listPairedDevices()); Set<BluetoothDevice> pairedDevices =
btnTurnOff.setOnClickListener(v -> bluetoothAdapter.getBondedDevices();
turnOffBluetooth()); if (pairedDevices.size() > 0) {
} StringBuilder stringBuilder = new
StringBuilder();
// Turn Bluetooth ON for (BluetoothDevice device : pairedDevices) {
private void turnOnBluetooth() { stringBuilder.append(device.getName())
if (!bluetoothAdapter.isEnabled()) { .append(" - ")
Intent enableBtIntent = new .append(device.getAddress())
Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); .append("\n");
if (ActivityCompat.checkSelfPermission(this, }
android.Manifest.permission.BLUETOOTH_CONNECT) tvOutput.setText(stringBuilder.toString());
!= PackageManager.PERMISSION_GRANTED) { } else {
// TODO: Consider calling tvOutput.setText("No paired devices
// ActivityCompat#requestPermissions found.");
// here to request the missing permissions, }
and then overriding } else {
// public void Toast.makeText(this, "Please turn on Bluetooth
onRequestPermissionsResult(int requestCode, String[] first", Toast.LENGTH_SHORT).show();
permissions, }
// int[] grantResults) }
// to handle the case where the user grants
the permission. See the documentation // Turn Bluetooth OFF
// for ActivityCompat#requestPermissions for private void turnOffBluetooth() {
more details. if (bluetoothAdapter.isEnabled()) {
return; if (ActivityCompat.checkSelfPermission(this,
} android.Manifest.permission.BLUETOOTH_CONNECT)
startActivityForResult(enableBtIntent, 1); != PackageManager.PERMISSION_GRANTED) {
} else { // TODO: Consider calling
Toast.makeText(this, "Bluetooth is already ON", // ActivityCompat#requestPermissions
Toast.LENGTH_SHORT).show(); // here to request the missing permissions,
} and then overriding
} // public void
onRequestPermissionsResult(int requestCode, String[]
permissions,
private void makeBluetoothVisible() { // int[] grantResults)
if (bluetoothAdapter.isEnabled()) { // to handle the case where the user grants
Intent discoverableIntent = new the permission. See the documentation
Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVER // for ActivityCompat#requestPermissions for
ABLE); more details.
return;
 }
bluetoothAdapter.disable();
Toast.makeText(this, "Bluetooth turned off",
Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(this, "Bluetooth is already OFF",
Toast.LENGTH_SHORT).show();
}
}
}

output :
get visible button :