Bluetooth Tutorial
Bluetooth is a way to exchange data with other devices wirelessly. Android provides Bluetooth API to perform several tasks such as:
- scan bluetooth devices
- connect and transfer data from and to other devices
- manage multiple connections etc.
Android Bluetooth API
The android.bluetooth package provides a lot of interfaces classes to work with bluetooth such as:
- BluetoothAdapter
- BluetoothDevice
- BluetoothSocket
- BluetoothServerSocket
- BluetoothClass
- BluetoothProfile
- BluetoothProfile.ServiceListener
- BluetoothHeadset
- BluetoothA2dp
- BluetoothHealth
- BluetoothHealthCallback
- BluetoothHealthAppConfiguration
android-preferences-example
BluetoothAdapter class
By the help of BluetoothAdapter class, we can perform fundamental tasks such as initiate device discovery, query a list of paired (bonded) devices, create a BluetoothServerSocket instance to listen for connection requests etc.
Constants of BluetoothAdapter class
BluetoothAdapter class provides many constants. Some of them are as follows.
- String ACTION_REQUEST_ENABLE
- String ACTION_REQUEST_DISCOVERABLE
- String ACTION_DISCOVERY_STARTED
- String ACTION_DISCOVERY_FINISHED
Methods of BluetoothAdapter class
Commonly used methods of BluetoothAdapter class are as follows:
- static synchronized BluetoothAdapter getDefaultAdapter() returns the instance of BluetoothAdapter.
- boolean enable() enables the bluetooth adapter if it is disabled.
- boolean isEnabled() returns true if the bluetooth adapter is enabled.
- boolean disable() disables the bluetooth adapter if it is enabled.
- String getName() returns the name of the bluetooth adapter.
- boolean setName(String name) changes the bluetooth name.
- int getState() returns the current state of the local bluetooth adapter.
- Set<BluetoothDevice> getBondedDevices() returns a set of paired (bonded) BluetoothDevice objects.
- boolean startDiscovery() starts the discovery process.
Android Bluetooth Example: enable, disable and make discovrable bluetooth programmatically
You need to write few lines of code only, to enable or disable the bluetooth.
activity_main.xml
Drag one textview and three buttons from the pallete, now the activity_main.xml file will like this:
File: activity_main.xml
<RelativeLayout xmlns:androclass="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<TextView android:text=""
android:id="@+id/out"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="30dp"
android:layout_marginTop="49dp"
android:text="TURN_ON" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button1"
android:layout_below="@+id/button1"
android:layout_marginTop="27dp"
android:text="DISCOVERABLE" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button2"
android:layout_below="@+id/button2"
android:layout_marginTop="28dp"
android:text="TURN_OFF" />
</RelativeLayout>
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<TextView android:text=""
android:id="@+id/out"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="30dp"
android:layout_marginTop="49dp"
android:text="TURN_ON" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button1"
android:layout_below="@+id/button1"
android:layout_marginTop="27dp"
android:text="DISCOVERABLE" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/button2"
android:layout_below="@+id/button2"
android:layout_marginTop="28dp"
android:text="TURN_OFF" />
</RelativeLayout>
Provide Permission
You need to provide following permissions in AndroidManifest.xml file.
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
The full code of AndroidManifest.xml file is given below.
File: AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:androclass="http://schemas.android.com/apk/res/android"
package="com.example.bluetooth"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="16" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.bluetooth.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
<manifest xmlns:androclass="http://schemas.android.com/apk/res/android"
package="com.example.bluetooth"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="16" />
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.bluetooth.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Activity class
Let's write the code to enable, disable and make bluetooth discoverable.
File: MainActivity.java
package com.example.bluetooth;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final int REQUEST_ENABLE_BT = 0;
private static final int REQUEST_DISCOVERABLE_BT = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView out=(TextView)findViewById(R.id.out);
final Button button1 = (Button) findViewById(R.id.button1);
final Button button2 = (Button) findViewById(R.id.button2);
final Button button3 = (Button) findViewById(R.id.button3);
final BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
out.append("device not supported");
}
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
if (!mBluetoothAdapter.isDiscovering()) {
//out.append("MAKING YOUR DEVICE DISCOVERABLE");
Toast.makeText(getApplicationContext(), "MAKING YOUR DEVICE DISCOVERABLE",
Toast.LENGTH_LONG);
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
startActivityForResult(enableBtIntent, REQUEST_DISCOVERABLE_BT);
}
}
});
button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
mBluetoothAdapter.disable();
//out.append("TURN_OFF BLUETOOTH");
Toast.makeText(getApplicationContext(), "TURNING_OFF BLUETOOTH", Toast.LENGTH_LONG);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
private static final int REQUEST_ENABLE_BT = 0;
private static final int REQUEST_DISCOVERABLE_BT = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView out=(TextView)findViewById(R.id.out);
final Button button1 = (Button) findViewById(R.id.button1);
final Button button2 = (Button) findViewById(R.id.button2);
final Button button3 = (Button) findViewById(R.id.button3);
final BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
out.append("device not supported");
}
button1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
if (!mBluetoothAdapter.isDiscovering()) {
//out.append("MAKING YOUR DEVICE DISCOVERABLE");
Toast.makeText(getApplicationContext(), "MAKING YOUR DEVICE DISCOVERABLE",
Toast.LENGTH_LONG);
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
startActivityForResult(enableBtIntent, REQUEST_DISCOVERABLE_BT);
}
}
});
button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
mBluetoothAdapter.disable();
//out.append("TURN_OFF BLUETOOTH");
Toast.makeText(getApplicationContext(), "TURNING_OFF BLUETOOTH", Toast.LENGTH_LONG);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
