将 Android RecognizerIntent 与蓝牙耳机一起使用

Question

我使用以下代码在 Android 中启动语音识别：

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);

这很好用。但是，它似乎不接受来自使用“电话音频”配置文件配对和连接的蓝牙耳机的语音输入。

我可以使用名为SoundAbout 的应用程序将“媒体音频”强制为“蓝牙（单声道）（SCO）”。有了这个应用程序集，我的语音识别现在可以从我的耳机中获取我的语音输入。

如何使用 RecognizerIntent 并从蓝牙耳机获取语音输入？

我看到在 API 级别 16 中有一个新的意图操作 ACTION_VOICE_SEARCH_HANDS_FREE。这对我来说太新了，但是这能解决我的问题吗？

我是否必须在 AudioManager 中混混（就像我假设 SoundAbout 正在做的那样）才能使用 setBluetoothScoOn() 或 startBluetoothSco() 路由音频输入？

Answer 1

清单权限

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BROADCAST_STICKY" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />  

在Activity 或Service 中创建一个内部类BluetoothHelper extends BluetoothHeadSetUtils。声明一个类成员mBluetoothHelper并在onCreate()中实例化它

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()
    {

    }
}

要将蓝牙耳机与 Text To Speech 一起使用，您需要在调用 speak 之前将 AudioManager 设置为 STREAM_VOICE_CALL。或者使用下面的代码

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);
}

将 BluetoothHeadsetUtils 类复制到您的项目中。

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"); //$NON-NLS-1$
        }
    };

}  

（2013 年 4 月 30 日）在必要时进行编辑以更改为 @TargetApi(Build.VERSION_CODES.HONEYCOMB)。如果您对 API 8 或 9 的 java.lang.NoClassDefFoundError 有问题，只需删除所有 API >= 11 代码。 startBluetoothSco() 适用于所有 API 版本。

Answer 2

我认为您所要做的就是更改应用程序的音频设置。

当您想通过蓝牙接收和发送耳机的声音时，您应该输入以下代码。

 AudioManager audioManager;

audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);

audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);
audioManager.startBluetoothSco();
audioManager.setBluetoothScoOn(true);

不使用蓝牙的时候别忘了按以下方法恢复手机的正常设置。

audioManager.setMode(AudioManager.MODE_NORMAL);
audioManager.stopBluetoothSco();
audioManager.setBluetoothScoOn(false);

所需的权限如下：

<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

很简单！

Answer 3

即使蓝牙耳机已配对并连接到电话音频配置文件 (HF/HS)，实际音频连接 (SCO) 也仅在来电并被接听时建立。

为了让您的 VR 应用程序接受来自蓝牙耳机的语音输入，您的应用程序必须在某些 VR 输入触发器上建立到耳机的 SCO， 您将需要使用以下内容 - isBluetoothScoAvailableOffCall 检查平台是否支持此功能，然后使用 startBluetoothSco 和 stopBluetoothSco 启动 SCO 到耳机。

Answer 4

startBluetoothSco需要很长时间才能建立，如果你需要用它来进行语音控制，这是个问题。

有没有一种快速的方法可以使用蓝牙麦克风听，然后在听完后将其关闭？

如果连接一直处于开启状态，则无法通过 A2DP 流式传输音频。

所以，理想世界：

通过 A2DP 音频输出。当它开始收听时，它使用 SCO 蓝牙麦克风。任何响应都是 A2DP。

事实上，如果它已经连接 - 你可以通过将媒体流更改为调用流来即时切换吗？如果有，是否有明显的延迟？

Answer 5

添加这些权限：

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.BROADCAST_STICKY" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />

然后为蓝牙创建一个广播接收器。

public class BTReceiver extends BroadcastReceiver {
    private static final String TAG = "BTReceiver";
    int state = 0;
    AudioManager audioManager;

    @Override
    public void onReceive(Context context, Intent intent) {
        Log.d("Z", "Received: Bluetooth");
        try {
            Bundle extras = intent.getExtras();
            if (extras != null) { //Do something
                audioManager = (AudioManager) context.getSystemService(AUDIO_SERVICE);

                String action = intent.getAction();
                Toast.makeText(context, action, Toast.LENGTH_LONG).show();
                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) {
                        setModeBluetooth();
                    } else if (state == BluetoothHeadset.STATE_DISCONNECTED) {
                        // Calling stopVoiceRecognition always returns false here
                        // as it should since the headset is no longer connected.
                        setModeNormal();

                        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");  //$NON-NLS-1$
                        setModeBluetooth();
                    } else if (state == BluetoothHeadset.STATE_AUDIO_DISCONNECTED) {
                        setModeNormal();
                        Log.d(TAG, "Headset audio disconnected"); //$NON-NLS-1$
                    }
                }
            }
        } catch (Exception e) {
            Log.d("Exception", "Exception " + e.toString());
        }
    }


    private void setModeBluetooth() {
        try {

            audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);
            audioManager.startBluetoothSco();
            audioManager.setBluetoothScoOn(true);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void setModeNormal() {
        try {
            audioManager.setMode(AudioManager.MODE_NORMAL);
            audioManager.stopBluetoothSco();
            audioManager.setBluetoothScoOn(false);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

在 Manifest 中注册接收者：

 <receiver
            android:name=".speech.BTReceiver"
            android:enabled="true"
            android:permission="android.permission.BLUETOOTH">
            <intent-filter>
                <action android:name="android.bluetooth.adapter.action.CONNECTION_STATE_CHANGED" />
            </intent-filter>
        </receiver>

在您的活动中注册和取消注册此接收器：

首先初始化它，在onCreate中

 mHeadsetBroadcastReceiver = new BTReceiver();

然后

@Override
protected void onResume() {
    super.onResume();

    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));
}

@Override
protected void onPause() {
    unregisterReceiver(mHeadsetBroadcastReceiver);

    super.onPause();
}

Answer 6

Hoan Nguyen 做得很好！
测试他的代码我注意到在某些情况下 stopBluetoothSco() 没有被调用。

我建议对 CountDownTimer 做一点改动：

private CountDownTimer mCountDown11 = new CountDownTimer(10000, 1000)
{
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @SuppressWarnings("synthetic-access")
    @Override
    public void onTick(long millisUntilFinished)
    {

        mBluetoothHeadset.startVoiceRecognition(mConnectedHeadset);

        Log.d(TAG, "onTick startVoiceRecognition"); //$NON-NLS-1$
    }

    @SuppressWarnings("synthetic-access")
    @Override
    public void onFinish()
    {
        mIsCountDownOn = false;

        /* START EDIT: Unregister broadcast receivers and stop Sco audio connection
           and cancel count down if fails to connect. */

        stopBluetooth11();

        /* END EDIT */

        Log.d(TAG, "\nonFinish fail to connect to headset audio"); //$NON-NLS-1$
    }
};