I wrote some codes for detecting the bluetooth headset connection and start audio through the headset. For API 11 and later, one can call startVoiceRecognition when the headset is connected. So a couple of use cases is as follow:
Headset was turned on before the application launches
The application should check for headset connected on start and establishes audio connection.User turns on headset during lifetime of the application
The application should register for broadcast of headset connection state and start audio connection when receive connected state.
There is a problem with the second use case. When received the connected state, I call startVoiceRecognition, but it always return false. So I have to implement a timer and after about a second the call will return true. I guess the OS and the headset need sometime to have everything ready to work. Does anybody know how to get headset audio connection without implement a timer. If it is not possible, should it be the OS that should take care of this situation (for example a READY_FOR_AUDIO_CONNECTION broadcast) instead of the application?
Below is the complete working code for API 11 or later.
Manifest permissions
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BROADCAST_STICKY" />
Code
public class MainActivity extends Activity
{
protected TextView mInfoTextview;
protected BluetoothAdapter mBluetoothAdapter;
protected BluetoothHeadset mBluetoothHeadset;
protected BluetoothDevice mConnectedHeadset;
protected AudioManager mAudioManager;
private static final String TAG = "Bluetooth Headset"; //$NON-NLS-1$
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mInfoTextview = (TextView) findViewById(R.id.main_textview);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter != null)
{
mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
if (mAudioManager.isBluetoothScoAvailableOffCall())
{
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
{
mBluetoothAdapter.getProfileProxy(this, mHeadsetProfileListener, BluetoothProfile.HEADSET);
}
}
}
}
@Override
protected void onDestroy()
{
super.onDestroy();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
{
if (mBluetoothHeadset != null)
{
// Need to call stopVoiceRecognition here when the app
// change orientation or close with headset still turns on.
mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
unregisterReceiver(mHeadsetBroadcastReceiver);
mCountDown.cancel();
}
mBluetoothAdapter.closeProfileProxy(BluetoothProfile.HEADSET, mBluetoothHeadset);
}
Log.d(TAG, "onDestroy"); //$NON-NLS-1$
}
protected BluetoothProfile.ServiceListener mHeadsetProfileListener = new BluetoothProfile.ServiceListener()
{
/**
* This method is never called, even when we closeProfileProxy on onPause.
* When or will it ever be called???
*/
@Override
public void onServiceDisconnected(int profile)
{
Log.d(TAG, "Profile listener onServiceDisconnected"); //$NON-NLS-1$
mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
unregisterReceiver(mHeadsetBroadcastReceiver);
mBluetoothHeadset = null;
}
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy)
{
Log.d(TAG, "Profile listener onServiceConnected"); //$NON-NLS-1$
// mBluetoothHeadset is just a head set profile,
// it does not represent a head set device.
mBluetoothHeadset = (BluetoothHeadset) proxy;
// If a head set is connected before this application starts,
// ACTION_CONNECTION_STATE_CHANGED will not be broadcast.
// So we need to check for already connected head set.
List<BluetoothDevice> devices = mBluetoothHeadset.getConnectedDevices();
if (devices.size() > 0)
{
// Only one head set can be connected at a time,
// so the connected head set is at index 0.
mConnectedHeadset = devices.get(0);
String log;
// The audio should not yet be connected at this stage.
// But just to make sure we check.
if (mBluetoothHeadset.isAudioConnected(mConnectedHeadset))
{
log = "Profile listener audio already connected"; //$NON-NLS-1$
}
else
{
// The if statement is just for debug. So far startVoiceRecognition always
// returns true here. What can we do if it returns false? Perhaps the only
// sensible thing is to inform the user.
// Well actually, it only returns true if a call to stopVoiceRecognition is
// call somewhere after a call to startVoiceRecognition. Otherwise, if
// stopVoiceRecognition is never called, then when the application is restarted
// startVoiceRecognition always returns false whenever it is called.
if (mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset))
{
log = "Profile listener startVoiceRecognition returns true"; //$NON-NLS-1$
}
else
{
log = "Profile listener startVoiceRecognition returns false"; //$NON-NLS-1$
}
}
mInfoTextview.setText("Device name = " + mConnectedHeadset.getName() //$NON-NLS-1$
+ "\n\n" + log); //$NON-NLS-1$
Log.d(TAG, log);
}
// During the active life time of the app, a user may turn on and off the head set.
// So register for broadcast of connection states.
registerReceiver(mHeadsetBroadcastReceiver,
new IntentFilter(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED));
// Calling startVoiceRecognition does not result in immediate audio connection.
// So register for broadcast of audio connection states. This broadcast will
// only be sent if startVoiceRecognition returns true.
registerReceiver(mHeadsetBroadcastReceiver,
new IntentFilter(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED));
}
};
protected BroadcastReceiver mHeadsetBroadcastReceiver = new BroadcastReceiver()
{
@Override
public void onReceive(Context context, Intent intent)
{
String action = intent.getAction();
int state;
int previousState = intent.getIntExtra(BluetoothHeadset.EXTRA_PREVIOUS_STATE, BluetoothHeadset.STATE_DISCONNECTED);
String log = ""; //$NON-NLS-1$
if (action.equals(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED))
{
state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_DISCONNECTED);
if (state == BluetoothHeadset.STATE_CONNECTED)
{
mConnectedHeadset = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
mInfoTextview.append("\n\nDevice name = " + mConnectedHeadset.getName()); //$NON-NLS-1$
// Audio should not be connected yet but just to make sure.
if (mBluetoothHeadset.isAudioConnected(mConnectedHeadset))
{
log = "Headset connected audio already connected"; //$NON-NLS-1$
}
else
{
// Calling startVoiceRecognition always returns false here,
// that why a count down timer is implemented to call
// startVoiceRecognition in the onTick and onFinish.
if (mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset))
{
log = "Headset connected startVoiceRecognition returns true"; //$NON-NLS-1$
}
else
{
log = "Headset connected startVoiceRecognition returns false"; //$NON-NLS-1$
mCountDown.start();
}
}
}
else if (state == BluetoothHeadset.STATE_DISCONNECTED)
{
// Calling stopVoiceRecognition always returns false here
// as it should since the headset is no longer connected.
mConnectedHeadset = null;
}
}
else // audio
{
state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_AUDIO_DISCONNECTED);
if (state == BluetoothHeadset.STATE_AUDIO_CONNECTED)
{
log = "Head set audio connected, cancel countdown timer"; //$NON-NLS-1$
mCountDown.cancel();
}
else if (state == BluetoothHeadset.STATE_AUDIO_DISCONNECTED)
{
// The headset audio is disconnected, but calling
// stopVoiceRecognition always returns true here.
boolean returnValue = mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
log = "Audio disconnected stopVoiceRecognition return " + returnValue; //$NON-NLS-1$
}
}
log += "\nAction = " + action + "\nState = " + state //$NON-NLS-1$ //$NON-NLS-2$
+ " previous state = " + previousState; //$NON-NLS-1$
mInfoTextview.append("\n\n" + log); //$NON-NLS-1$
Log.d(TAG, log);
}
};
protected CountDownTimer mCountDown = new CountDownTimer(10000, 1000)
{
@Override
public void onTick(long millisUntilFinished)
{
String log;
if (mBluetoothHeadset.isAudioConnected(mConnectedHeadset))
{
log = "\nonTick audio already connected"; //$NON-NLS-1$
}
else
{
// First stick calls always returns false. The second stick
// always returns true if the countDownInterval is set to 1000.
// It is somewhere in between 500 to a 1000.
if (mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset))
{
log = "\nonTick startVoiceRecognition returns true"; //$NON-NLS-1$
}
else
{
log = "\nonTick startVoiceRecognition returns false"; //$NON-NLS-1$
}
}
mInfoTextview.append(log);
Log.d(TAG, log);
}
@Override
public void onFinish()
{
String log;
if (mBluetoothHeadset.isAudioConnected(mConnectedHeadset))
{
log = "\nonFinish audio already connected"; //$NON-NLS-1$
}
else
{
if (mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset))
{
log = "\nonFinish startVoiceRecognition returns true"; //$NON-NLS-1$
}
else
{
log = "\nonFinish startVoiceRecognition returns false"; //$NON-NLS-1$
}
}
mInfoTextview.append(log);
Log.d(TAG, log);
}
};
}
Layout File
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="@+id/main_textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textIsSelectable="false" />
</ScrollView>