How do you use Bluetooth on Android
To exchange data with other devices wirelessly, Bluetooth is used. The Bluetooth framework supported by the Android platform allows a device to send or receive data between two different devices. The Bluetooth API of Android is used to perform these tasks and many more:
To scan Bluetooth devices
To connect and transfer data from and to other devices
To manage multiple connections
Android Bluetooth API:
The interfaces classes to work with Bluetooth are included in the android.bluetooth package. These are:
- BluetoothAdapter
- BluetoothDevice
- BluetoothSocket
- BluetoothServerSocket
- BluetoothClass
- BluetoothProfile
- BluetoothProfile.ServiceListener
- BluetoothHeadset
- BluetoothA2dp
- BluetoothHealth
- BluetoothHealthCallback
- BluetoothHealthAppConfiguration
BluetoothAdapter class:
To perform the fundamental tasks, like to initiate a device discovery, to query a list of paired or bonded devices, to create a BluetoothServerSocket instance to listen for connection requests, etc, the BluetoothAdapter class is used.
Constants of BluetoothAdapter class:
There are various constants provided by the BluetoothAdapter class. Some of these constants are:
- String ACTION_REQUEST_ENABLE
- String ACTION_REQUEST_DISCOVERABLE
- String ACTION_DISCOVERY_STARTED
- String ACTION_DISCOVERY_FINISHED
Methods of BluetoothAdapter class:
The BluetoothAdapter class contains various methods. Some of the important methods of the BluetoothAdapter class are:
- static synchronized BluetoothAdapter getDefaultAdapter(): Used to return the instance of BluetoothAdapter.
- boolean enable(): Used to enable the Bluetooth adapter, if it is disabled.
- boolean isEnabled(): Used to return true if the Bluetooth adapter is enabled.
- boolean disable(): Used to disable the Bluetooth adapter, if it is enabled.
- String getName(): Used to return the name of the Bluetooth adapter.
- boolean setName(String name): Used to change the Bluetooth name.
- int getState(): Used to return the current state of the local Bluetooth adapter.
- Set getBondedDevices(): Used to return a set of paired or bonded BluetoothDevice objects.
- boolean startDiscovery(): Used to start the discovery process.
Example: To enable, disable, and make discoverable Bluetooth programmatically:
activity_main.xml:
In the activity_main.xml file, we will drag a Textview and three buttons from the pallet.
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AndroidManifest.xml:
In the AndroidManifest.xml file, we will provide the below permissions:
Syntax:
File: AndroidManifest.xml:
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Activity class:(File: MainActivity.java)
In the MainActivity.java file, we will write the code to enable, disable, and to make the Bluetooth discoverable.
package com.example.radioapp;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
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 Activity {
Button b1,b2,b3,b4;
private BluetoothAdapter BA;
private SetpairedDevices;
ListView lv;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = (Button) findViewById(R.id.button);
b2=(Button)findViewById(R.id.button2);
b3=(Button)findViewById(R.id.button3);
b4=(Button)findViewById(R.id.button4);
BA = BluetoothAdapter.getDefaultAdapter();
lv = (ListView)findViewById(R.id.listView);
}
public void on(View v){
if (!BA.isEnabled()) {
Intent turnOn = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(turnOn, 0);
Toast.makeText(getApplicationContext(), "Turned on",Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getApplicationContext(), "Already on", Toast.LENGTH_LONG).show();
}
}
public void off(View v){
BA.disable();
Toast.makeText(getApplicationContext(), "Turned off" ,Toast.LENGTH_LONG).show();
}
public void visible(View v){
Intent getVisible = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
startActivityForResult(getVisible, 0);
}
public void list(View v){
pairedDevices = BA.getBondedDevices();
ArrayList list = new ArrayList();
for(BluetoothDevice bt : pairedDevices) list.add(bt.getName());
Toast.makeText(getApplicationContext(), "Showing Paired Devices",Toast.LENGTH_SHORT).show();
final ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_1, list);
lv.setAdapter(adapter);
}
} |
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