Using the Android RecognizerIntent with a bluetooth headset
I use the following code to launch speech recognition in Android:
PackageManager pm = getPackageManager();
List<ResolveInfo> activities = pm.queryIntentActivities(new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
if (activities.size() == 0) {
displayWarning("This device does not support speech recognition");
return;
}
Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
This works fine. However, it doesn't seem to accept voice input from a bluetooth headset that is paired and connected using the "Phone audio" profile.
I can use an app called SoundAbout to force "Media Audio" to "Bluetooth (mono) (SCO)". With this app set, my voice recognition now works taking my speech input from my headset.
How can I use RecognizerIntent and get speech input from a bluetooth headset?
I see in API level 16 there is a new intent action ACTION_VOICE_SEARCH_HANDS_FREE. This is too new for me to use, but would this solve my problem?
Do I have to muck around in the AudioManager (like I assume SoundAbout is doing) to route the audio input using setBluetoothScoOn() or startBluetoothSco()?
Answer
Manifest permission
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BROADCAST_STICKY" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
Create an inner class BluetoothHelper extends BluetoothHeadSetUtils in your Activity or Service. Declare a class member mBluetoothHelper and instantiate it in onCreate()
BluetoothHelper mBluetoothHelper;
@Override
public void onCreate()
{
mBluetoothHelper = new BluetoothHelper(this);
}
@Override
onResume()
{
mBluetoothHelper.start();
}
@Override
onPause()
{
mBluetoothHelper.stop();
}
// inner class
// BluetoothHeadsetUtils is an abstract class that has
// 4 abstracts methods that need to be implemented.
private class BluetoothHelper extends BluetoothHeadSetUtils
{
public BluetoothHelper(Context context)
{
super(context);
}
@Override
public void onScoAudioDisconnected()
{
// Cancel speech recognizer if desired
}
@Override
public void onScoAudioConnected()
{
// Should start speech recognition here if not already started
}
@Override
public void onHeadsetDisconnected()
{
}
@Override
public void onHeadsetConnected()
{
}
}
To use bluetooth headset with Text To Speech you need to set the AudioManager to STREAM_VOICE_CALL before calling speak. Or use the code below
protected void speak(String text)
{
HashMap<String, String> myHashRender = new HashMap<String, String>();
if (mBluetoothHelper.isOnHeadsetSco())
{
myHashRender.put(TextToSpeech.Engine.KEY_PARAM_STREAM,
String.valueOf(AudioManager.STREAM_VOICE_CALL));
}
mTts.speak(text, TextToSpeech.QUEUE_FLUSH, myHashRender);
}
Copy the BluetoothHeadsetUtils class to your project.
import java.util.List;
import android.annotation.SuppressLint;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothClass;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothHeadset;
import android.bluetooth.BluetoothProfile;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.media.AudioManager;
import android.os.Build;
import android.os.CountDownTimer;
import android.util.Log;
/**
* This is a utility to detect bluetooth headset connection and establish audio connection
* for android API >= 8. This includes a work around for API < 11 to detect already connected headset
* before the application starts. This work around would only fails if Sco audio
* connection is accepted but the connected device is not a headset.
*
* @author Hoan Nguyen
*
*/
public abstract class BluetoothHeadsetUtils
{
private Context mContext;
private BluetoothAdapter mBluetoothAdapter;
private BluetoothHeadset mBluetoothHeadset;
private BluetoothDevice mConnectedHeadset;
private AudioManager mAudioManager;
private boolean mIsCountDownOn;
private boolean mIsStarting;
private boolean mIsOnHeadsetSco;
private boolean mIsStarted;
private static final String TAG = "BluetoothHeadsetUtils"; //$NON-NLS-1$
/**
* Constructor
* @param context
*/
public BluetoothHeadsetUtils(Context context)
{
mContext = context;
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
mAudioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);
}
/**
* Call this to start BluetoothHeadsetUtils functionalities.
* @return The return value of startBluetooth() or startBluetooth11()
*/
public boolean start()
{
if (!mIsStarted)
{
mIsStarted = true;
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)
{
mIsStarted = startBluetooth();
}
else
{
mIsStarted = startBluetooth11();
}
}
return mIsStarted;
}
/**
* Should call this on onResume or onDestroy.
* Unregister broadcast receivers and stop Sco audio connection
* and cancel count down.
*/
public void stop()
{
if (mIsStarted)
{
mIsStarted = false;
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB)
{
stopBluetooth();
}
else
{
stopBluetooth11();
}
}
}
/**
*
* @return true if audio is connected through headset.
*/
public boolean isOnHeadsetSco()
{
return mIsOnHeadsetSco;
}
public abstract void onHeadsetDisconnected();
public abstract void onHeadsetConnected();
public abstract void onScoAudioDisconnected();
public abstract void onScoAudioConnected();
/**
* Register for bluetooth headset connection states and Sco audio states.
* Try to connect to bluetooth headset audio by calling startBluetoothSco().
* This is a work around for API < 11 to detect if a headset is connected before
* the application starts.
*
* The official documentation for startBluetoothSco() states
*
* "This method can be used by applications wanting to send and received audio to/from
* a bluetooth SCO headset while the phone is not in call."
*
* Does this mean that startBluetoothSco() would fail if the connected bluetooth device
* is not a headset?
*
* Thus if a call to startBluetoothSco() is successful, i.e mBroadcastReceiver will receive
* an ACTION_SCO_AUDIO_STATE_CHANGED with intent extra SCO_AUDIO_STATE_CONNECTED, then
* we assume that a headset is connected.
*
* @return false if device does not support bluetooth or current platform does not supports
* use of SCO for off call.
*/
@SuppressWarnings("deprecation")
private boolean startBluetooth()
{
Log.d(TAG, "startBluetooth"); //$NON-NLS-1$
// Device support bluetooth
if (mBluetoothAdapter != null)
{
if (mAudioManager.isBluetoothScoAvailableOffCall())
{
mContext.registerReceiver(mBroadcastReceiver,
new IntentFilter(BluetoothDevice.ACTION_ACL_CONNECTED));
mContext.registerReceiver(mBroadcastReceiver,
new IntentFilter(BluetoothDevice.ACTION_ACL_DISCONNECTED));
mContext.registerReceiver(mBroadcastReceiver,
new IntentFilter(AudioManager.ACTION_SCO_AUDIO_STATE_CHANGED));
// Need to set audio mode to MODE_IN_CALL for call to startBluetoothSco() to succeed.
mAudioManager.setMode(AudioManager.MODE_IN_CALL);
mIsCountDownOn = true;
// mCountDown repeatedly tries to start bluetooth Sco audio connection.
mCountDown.start();
// need for audio sco, see mBroadcastReceiver
mIsStarting = true;
return true;
}
}
return false;
}
/**
* Register a headset profile listener
* @return false if device does not support bluetooth or current platform does not supports
* use of SCO for off call or error in getting profile proxy.
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
private boolean startBluetooth11()
{
Log.d(TAG, "startBluetooth11"); //$NON-NLS-1$
// Device support bluetooth
if (mBluetoothAdapter != null)
{
if (mAudioManager.isBluetoothScoAvailableOffCall())
{
// All the detection and audio connection are done in mHeadsetProfileListener
if (mBluetoothAdapter.getProfileProxy(mContext,
mHeadsetProfileListener,
BluetoothProfile.HEADSET))
{
return true;
}
}
}
return false;
}
/**
* API < 11
* Unregister broadcast receivers and stop Sco audio connection
* and cancel count down.
*/
private void stopBluetooth()
{
Log.d(TAG, "stopBluetooth"); //$NON-NLS-1$
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mCountDown.cancel();
}
// Need to stop Sco audio connection here when the app
// change orientation or close with headset still turns on.
mContext.unregisterReceiver(mBroadcastReceiver);
mAudioManager.stopBluetoothSco();
mAudioManager.setMode(AudioManager.MODE_NORMAL);
}
/**
* API >= 11
* Unregister broadcast receivers and stop Sco audio connection
* and cancel count down.
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
protected void stopBluetooth11()
{
Log.d(TAG, "stopBluetooth11"); //$NON-NLS-1$
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mCountDown11.cancel();
}
if (mBluetoothHeadset != null)
{
// Need to call stopVoiceRecognition here when the app
// change orientation or close with headset still turns on.
mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
mContext.unregisterReceiver(mHeadsetBroadcastReceiver);
mBluetoothAdapter.closeProfileProxy(BluetoothProfile.HEADSET, mBluetoothHeadset);
mBluetoothHeadset = null;
}
}
/**
* Broadcast receiver for API < 11
* Handle headset and Sco audio connection states.
*/
private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver()
{
@SuppressWarnings({"deprecation", "synthetic-access"})
@Override
public void onReceive(Context context, Intent intent)
{
String action = intent.getAction();
if (action.equals(BluetoothDevice.ACTION_ACL_CONNECTED))
{
mConnectedHeadset = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
BluetoothClass bluetoothClass = mConnectedHeadset.getBluetoothClass();
if (bluetoothClass != null)
{
// Check if device is a headset. Besides the 2 below, are there other
// device classes also qualified as headset?
int deviceClass = bluetoothClass.getDeviceClass();
if (deviceClass == BluetoothClass.Device.AUDIO_VIDEO_HANDSFREE
|| deviceClass == BluetoothClass.Device.AUDIO_VIDEO_WEARABLE_HEADSET)
{
// start bluetooth Sco audio connection.
// Calling startBluetoothSco() always returns faIL here,
// that why a count down timer is implemented to call
// startBluetoothSco() in the onTick.
mAudioManager.setMode(AudioManager.MODE_IN_CALL);
mIsCountDownOn = true;
mCountDown.start();
// override this if you want to do other thing when the device is connected.
onHeadsetConnected();
}
}
Log.d(TAG, mConnectedHeadset.getName() + " connected"); //$NON-NLS-1$
}
else if (action.equals(BluetoothDevice.ACTION_ACL_DISCONNECTED))
{
Log.d(TAG, "Headset disconnected"); //$NON-NLS-1$
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mCountDown.cancel();
}
mAudioManager.setMode(AudioManager.MODE_NORMAL);
// override this if you want to do other thing when the device is disconnected.
onHeadsetDisconnected();
}
else if (action.equals(AudioManager.ACTION_SCO_AUDIO_STATE_CHANGED))
{
int state = intent.getIntExtra(AudioManager.EXTRA_SCO_AUDIO_STATE,
AudioManager.SCO_AUDIO_STATE_ERROR);
if (state == AudioManager.SCO_AUDIO_STATE_CONNECTED)
{
mIsOnHeadsetSco = true;
if (mIsStarting)
{
// When the device is connected before the application starts,
// ACTION_ACL_CONNECTED will not be received, so call onHeadsetConnected here
mIsStarting = false;
onHeadsetConnected();
}
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mCountDown.cancel();
}
// override this if you want to do other thing when Sco audio is connected.
onScoAudioConnected();
Log.d(TAG, "Sco connected"); //$NON-NLS-1$
}
else if (state == AudioManager.SCO_AUDIO_STATE_DISCONNECTED)
{
Log.d(TAG, "Sco disconnected"); //$NON-NLS-1$
// Always receive SCO_AUDIO_STATE_DISCONNECTED on call to startBluetooth()
// which at that stage we do not want to do anything. Thus the if condition.
if (!mIsStarting)
{
mIsOnHeadsetSco = false;
// Need to call stopBluetoothSco(), otherwise startBluetoothSco()
// will not be successful.
mAudioManager.stopBluetoothSco();
// override this if you want to do other thing when Sco audio is disconnected.
onScoAudioDisconnected();
}
}
}
}
};
/**
* API < 11
* Try to connect to audio headset in onTick.
*/
private CountDownTimer mCountDown = new CountDownTimer(10000, 1000)
{
@SuppressWarnings("synthetic-access")
@Override
public void onTick(long millisUntilFinished)
{
// When this call is successful, this count down timer will be canceled.
mAudioManager.startBluetoothSco();
Log.d(TAG, "\nonTick start bluetooth Sco"); //$NON-NLS-1$
}
@SuppressWarnings("synthetic-access")
@Override
public void onFinish()
{
// Calls to startBluetoothSco() in onStick are not successful.
// Should implement something to inform user of this failure
mIsCountDownOn = false;
mAudioManager.setMode(AudioManager.MODE_NORMAL);
Log.d(TAG, "\nonFinish fail to connect to headset audio"); //$NON-NLS-1$
}
};
/**
* API >= 11
* Check for already connected headset and if so start audio connection.
* Register for broadcast of headset and Sco audio connection states.
*/
private 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"); //$NON-NLS-1$
stopBluetooth11();
}
@SuppressWarnings("synthetic-access")
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
public void onServiceConnected(int profile, BluetoothProfile proxy)
{
Log.d(TAG, "Profile listener onServiceConnected"); //$NON-NLS-1$
// mBluetoothHeadset is just a headset profile,
// it does not represent a headset device.
mBluetoothHeadset = (BluetoothHeadset) proxy;
// If a headset is connected before this application starts,
// ACTION_CONNECTION_STATE_CHANGED will not be broadcast.
// So we need to check for already connected headset.
List<BluetoothDevice> devices = mBluetoothHeadset.getConnectedDevices();
if (devices.size() > 0)
{
// Only one headset can be connected at a time,
// so the connected headset is at index 0.
mConnectedHeadset = devices.get(0);
onHeadsetConnected();
// Should not need count down timer, but just in case.
// See comment below in mHeadsetBroadcastReceiver onReceive()
mIsCountDownOn = true;
mCountDown11.start();
Log.d(TAG, "Start count down"); //$NON-NLS-1$
}
// During the active life time of the app, a user may turn on and off the headset.
// So register for broadcast of connection states.
mContext.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.
mContext.registerReceiver(mHeadsetBroadcastReceiver,
new IntentFilter(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED));
}
};
/**
* API >= 11
* Handle headset and Sco audio connection states.
*/
private BroadcastReceiver mHeadsetBroadcastReceiver = new BroadcastReceiver()
{
@SuppressWarnings("synthetic-access")
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@Override
public void onReceive(Context context, Intent intent)
{
String action = intent.getAction();
int state;
if (action.equals(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED))
{
state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE,
BluetoothHeadset.STATE_DISCONNECTED);
Log.d(TAG, "\nAction = " + action + "\nState = " + state); //$NON-NLS-1$ //$NON-NLS-2$
if (state == BluetoothHeadset.STATE_CONNECTED)
{
mConnectedHeadset = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// Calling startVoiceRecognition always returns false here,
// that why a count down timer is implemented to call
// startVoiceRecognition in the onTick.
mIsCountDownOn = true;
mCountDown11.start();
// override this if you want to do other thing when the device is connected.
onHeadsetConnected();
Log.d(TAG, "Start count down"); //$NON-NLS-1$
}
else if (state == BluetoothHeadset.STATE_DISCONNECTED)
{
// Calling stopVoiceRecognition always returns false here
// as it should since the headset is no longer connected.
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mCountDown11.cancel();
}
mConnectedHeadset = null;
// override this if you want to do other thing when the device is disconnected.
onHeadsetDisconnected();
Log.d(TAG, "Headset disconnected"); //$NON-NLS-1$
}
}
else // audio
{
state = intent.getIntExtra(BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_AUDIO_DISCONNECTED);
Log.d(TAG, "\nAction = " + action + "\nState = " + state); //$NON-NLS-1$ //$NON-NLS-2$
if (state == BluetoothHeadset.STATE_AUDIO_CONNECTED)
{
Log.d(TAG, "\nHeadset audio connected"); //$NON-NLS-1$
mIsOnHeadsetSco = true;
if (mIsCountDownOn)
{
mIsCountDownOn = false;
mCountDown11.cancel();
}
// override this if you want to do other thing when headset audio is connected.
onScoAudioConnected();
}
else if (state == BluetoothHeadset.STATE_AUDIO_DISCONNECTED)
{
mIsOnHeadsetSco = false;
// The headset audio is disconnected, but calling
// stopVoiceRecognition always returns true here.
mBluetoothHeadset.stopVoiceRecognition(mConnectedHeadset);
// override this if you want to do other thing when headset audio is disconnected.
onScoAudioDisconnected();
Log.d(TAG, "Headset audio disconnected"); //$NON-NLS-1$
}
}
}
};
/**
* API >= 11
* Try to connect to audio headset in onTick.
*/
private CountDownTimer mCountDown11 = new CountDownTimer(10000, 1000)
{
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@SuppressWarnings("synthetic-access")
@Override
public void onTick(long millisUntilFinished)
{
// 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.
mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset);
Log.d(TAG, "onTick startVoiceRecognition"); //$NON-NLS-1$
}
@SuppressWarnings("synthetic-access")
@Override
public void onFinish()
{
// Calls to startVoiceRecognition in onStick are not successful.
// Should implement something to inform user of this failure
mIsCountDownOn = false;
Log.d(TAG, "\nonFinish fail to connect to headset audio"); //$NON-NLS-1$
}
};
}
(April 30 2013) Edit to change to @TargetApi(Build.VERSION_CODES.HONEYCOMB) when necessary. If you have problem with java.lang.NoClassDefFoundError for API 8 or 9, just remove all the API >= 11 codes. The startBluetoothSco() works for all API versions.