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捕获Android媒体按钮事件

androidandroid-mediaplayerandroidxandroid-mediasession
8
我有一个应用程序，启动一个前台服务播放一些媒体内容。我希望能够通过智能手表或耳机上的媒体按钮来控制它，并且还能从媒体样式通知中控制它。
然而，我发现无法始终正确地使用这些媒体按钮。在日志中，我可以看到它们经常被发送到其他应用程序，即使我先启动了MediaSession和播放也是如此。
尽管我已经定义了一个MediaCallback并且设置setActive(true)，但我仍然无法让它正常工作。
清单文件：
<service
    android:name=".services.MediaControllerService"
    android:enabled="true"
    android:exported="true"
    android:permission="android.permission.FOREGROUND_SERVICE">
    <intent-filter android:priority="999">
        <action android:name="android.intent.action.MEDIA_BUTTON"/>
    </intent-filter>
</service>

代码（注意包，这在Android 10中很困难，需要找到正确的包组合，才能一起使用并给我提供MediaStyle）...

import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.media.AudioAttributes;
import android.media.AudioFocusRequest;
import android.media.AudioManager;
import android.media.MediaMetadata;
import android.support.v4.media.MediaMetadataCompat;
import android.support.v4.media.session.MediaControllerCompat;
import android.support.v4.media.session.MediaSessionCompat;
import android.support.v4.media.session.PlaybackStateCompat;
import android.view.KeyEvent;
import androidx.annotation.Nullable;
import androidx.core.app.NotificationCompat;
import androidx.media.session.MediaButtonReceiver;

public class TextToSpeechMediaControllerService extends Service { 
    public static final String START_SERVICE_ACTION_INTENT = "serviceStart";
    private TextToSpeechPlayer player;
    private MediaMetadataCompat mediaMetaData;
    private MediaSessionCompat mediaSession;
    private TextToSpeechMediaControllerService.AudioFocusHelper mAudioFocusHelper;
    private AudioManager mAudioManager;
    private final String NOTIFICATION_CHANNEL_TEXT_TO_SPEECH_CONTROLS = "fp_tts_media_controls";
    public MediaControllerCompat.TransportControls transportControls;
    private String pageTitle;
    private String pageAddress;
    private String pageDomain;
    private SpeechBank currentSpeechBank;
    private MediaButtonReceiver mediaButtonReceiver;
    private AudioFocusRequest audioFocusRequest;
    private AudioAttributes playbackAttributes;
    private Handler handler;

    public TextToSpeechMediaControllerService() {
    }

    @Override
    public void onCreate() {
        Log.d("TTSMEDIAPLAYER", "---------- STARTING SERVICE ----------");
        player = new TextToSpeechPlayer(this);
        mAudioManager = (AudioManager) this.getSystemService(Context.AUDIO_SERVICE);
        mAudioFocusHelper = new TextToSpeechMediaControllerService.AudioFocusHelper();

        mediaSession = new MediaSessionCompat(this, "fpt2s");
        mediaSession.setCallback(callback);
        mediaSession.setActive(true);
        handler = new Handler(); // something to do with handling delayed focus https://developer.android.com/guide/topics/media-apps/audio-focus#audio-focus-change
        transportControls = mediaSession.getController().getTransportControls();
        NotificationChannel channel = null;
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            channel = new NotificationChannel(NOTIFICATION_CHANNEL_TEXT_TO_SPEECH_CONTROLS,
                    getString(R.string.media_controls_notification_channel_title),
                    NotificationManager.IMPORTANCE_HIGH);
            ((NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE)).createNotificationChannel(channel);
        }
        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d("TTSMEDIAPLAYER", "---------- onStartCOmmand ("+intent.getAction()+", startId) ----------");
        MediaButtonReceiver.handleIntent(mediaSession, intent); // Required to catch media button events and send them to mediasession callback
        if (intent !=null && intent.getExtras()!=null){
            int closeCommand = intent.getExtras().getInt("swipeToClose", 0);
            if(closeCommand==1){
                Log.d("TTSMEDIAPLAYER", "Close service intent received.");
                // Pre-lollipop media style close button. Unable to test
                stopSelf();
                return super.onStartCommand(intent, flags, startId);
            }
            //Request audio focus
            if (false ) { // mAudioFocusHelper.requestAudioFocus() == false not needed because we request focus onPlay
                Log.d("TTSMEDIAPLAYER", "Starting and requesting focus...");
                //Could not gain focus
                stopSelf();
            }else {
                Log.d("TTSMEDIAPLAYER", "Focued. Starting...");
                boolean isPlaying = player.isPlaying();
                String nodesAsJsonString = intent.getExtras().getString("nodesAsJsonString", "[]");
                if (nodesAsJsonString != null && !nodesAsJsonString.equals("[]")) {
                    isPlaying = true;
                    // New TTS playback has been requested
                    pageTitle = intent.getExtras().getString("pageTitle", "");
                    pageAddress = intent.getExtras().getString("pageAddress", "");
                    pageDomain = UrlHelper.getDomain(pageAddress, true, true, true);
                    final Locale languageToSpeak = UrlHelper.getLanguageFromAddress(pageAddress);

                    try {
                        currentSpeechBank = new SpeechBank(nodesAsJsonString, languageToSpeak);
                    } catch (JSONException e) {
                        stopSelf();
                        return super.onStartCommand(intent, flags, startId);
                    }
                    mediaMetaData = new MediaMetadataCompat.Builder()
                            // TODO i guessed at these, I think this might be used on things like bluetooth speakers that have a display
                            .putString(MediaMetadata.METADATA_KEY_ARTIST, pageAddress)
                            .putString(MediaMetadata.METADATA_KEY_TITLE, pageTitle)
                            .putString(MediaMetadata.METADATA_KEY_DISPLAY_TITLE, pageTitle)
                            .build();
                    mediaSession.setMetadata(mediaMetaData);
                }
                Log.d("TTSMEDIAPLAYER", "isPlaying: " + isPlaying);
                /*mediaSession.setFlags(
                        MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS | // apparently no longer needed
                                //MediaSession.FLAG_HANDLES_QUEUE_COMMANDS | //
                                MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS 
                );*/

                if(intent.getAction()!=null && intent.getAction().equals(START_SERVICE_ACTION_INTENT)) {
                    Log.d("TTSMEDIAPLAYER", "START_SERVICE_ACTION_INTENT detected, triggering transportcontrols.play");
                    transportControls.play();
                }
            }
        }
        return super.onStartCommand(intent, flags, startId); //  START_NOT_STICKY;?
    }

    private void updateNotificationAndMediaButtons(boolean isPlaying) {
        // ... notification stuff ...
        startForeground(1, notificationBuilder.build());
    }

    @Override
    public void onDestroy() {
        mediaSession.release();
        mAudioFocusHelper.abandonAudioFocus();
        player.freeUpResources();
        super.onDestroy();
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    private MediaSessionCompat.Callback callback = new MediaSessionCompat.Callback() {

        @Override
        public void onSkipToNext() {
            Log.d("TTSMEDIAPLAYER", "SKIP TO NEXT");
            super.onSkipToNext();
            handleFastForward();
        }

        @Override
        public void onPlay() {
            Log.d("TTSMEDIAPLAYER", "onPLAY!");
            if(mAudioFocusHelper.requestAudioFocus()) {
                if(player.isPaused()){
                    Log.d("TTSMEDIAPLAYER", "(resuming)");
                    player.resume();
                }else{
                    Log.d("TTSMEDIAPLAYER", "(not started? playNew)");
                    player.playNew(currentSpeechBank);
                }
                // TODO TTS textToSpeechPlayer.play();
                PlaybackStateCompat state = new PlaybackStateCompat.Builder()
                        // Supported actions in current state
                        .setActions(
                                PlaybackStateCompat.ACTION_PLAY | PlaybackStateCompat.ACTION_STOP
                                        | PlaybackStateCompat.ACTION_FAST_FORWARD | PlaybackStateCompat.ACTION_REWIND
                        )
                        // Current state
                        .setState(PlaybackStateCompat.STATE_PLAYING, player.getCurrentPosition(), 1, SystemClock.elapsedRealtime())
                        .build();
                mediaSession.setPlaybackState(state);
                updateNotificationAndMediaButtons(true);
            }
            super.onPlay();
        }

        @Override
        public void onPause() {
            Log.d("TTSMEDIAPLAYER", "onPAUSE!");
            player.pause();
            PlaybackStateCompat state = new PlaybackStateCompat.Builder()
                    // Set supported actions in current state
                    .setActions(
                            PlaybackStateCompat.ACTION_PLAY | PlaybackStateCompat.ACTION_STOP |
                                    PlaybackStateCompat.ACTION_FAST_FORWARD | PlaybackStateCompat.ACTION_REWIND)
                    // Set current state
                    .setState(PlaybackStateCompat.STATE_PAUSED, player.getCurrentPosition(), 1, SystemClock.elapsedRealtime())
                    .build();
            mediaSession.setPlaybackState(state);
            updateNotificationAndMediaButtons(false);
            super.onPause();
        }

        @Override
        public void onSkipToPrevious() {
            Log.d("TTSMEDIAPLAYER", "SKIP TRACK PREV!");
            player.rewind();
            super.onSkipToPrevious();
        }

        @Override
        public void onFastForward() {
            Log.d("TTSMEDIAPLAYER", "FAST FORWARD!");
            super.onFastForward();
            handleFastForward();
        }

        @Override
        public void onRewind() {
            Log.d("TTSMEDIAPLAYER", "REWIND!");
            player.rewind();
            PlaybackStateCompat state = new PlaybackStateCompat.Builder()
                    // Set supported actions in current state
                    .setActions(
                            PlaybackStateCompat.ACTION_PLAY | PlaybackStateCompat.ACTION_STOP |
                                    PlaybackStateCompat.ACTION_FAST_FORWARD | PlaybackStateCompat.ACTION_REWIND)
                    // Set current state
                    .setState(PlaybackStateCompat.STATE_PLAYING, player.getCurrentPosition(), 1, SystemClock.elapsedRealtime())
                    .build();
            mediaSession.setPlaybackState(state);
            updateNotificationAndMediaButtons(true);
            super.onRewind();
        }

        @Override
        public void onStop() {
            Log.d("TTSMEDIAPLAYER", "STOP!");
            player.stop();
            PlaybackStateCompat state = new PlaybackStateCompat.Builder()
                    // Set supported actions in current state
                    //    .setActions(null)
                    // Set current state
                    .setState(PlaybackStateCompat.STATE_STOPPED, player.getCurrentPosition(), 1, SystemClock.elapsedRealtime())
                    .build();
            mediaSession.setPlaybackState(state);
            mAudioFocusHelper.abandonAudioFocus();
            stopSelf();
            //super.onStop();
        }
    };

    private void handleFastForward() {
        boolean hasReachedEnd = player.fastForward();
        if(hasReachedEnd){
            transportControls.stop();
        }else{
            PlaybackStateCompat state = new PlaybackStateCompat.Builder()
                    // Set supported actions in current state
                    .setActions(
                            PlaybackStateCompat.ACTION_PAUSE | PlaybackStateCompat.ACTION_STOP |
                                    PlaybackStateCompat.ACTION_FAST_FORWARD | PlaybackStateCompat.ACTION_REWIND)
                    // Set current state
                    .setState(PlaybackStateCompat.STATE_PLAYING, player.getCurrentPosition(), 1, SystemClock.elapsedRealtime())
                    .build();
            mediaSession.setPlaybackState(state);
            updateNotificationAndMediaButtons(true);
        }
    }

    /**
     * Helper class for managing audio focus related tasks.
     */
    private final class AudioFocusHelper
            implements AudioManager.OnAudioFocusChangeListener {

        private boolean mPlayOnAudioFocus = false;

        private boolean requestAudioFocus() {
            Log.d("TTSMEDIAPLAYER", "requestAudioFocus()...");
            playbackAttributes = new AudioAttributes.Builder()
                    .setUsage(AudioAttributes.USAGE_MEDIA)
                    .setContentType(AudioAttributes.CONTENT_TYPE_SPEECH)
                    .build();

            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                audioFocusRequest = new AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
                        .setAudioAttributes(playbackAttributes)
                        .setAcceptsDelayedFocusGain(false)
                        .setOnAudioFocusChangeListener(mAudioFocusHelper, handler)
                        .build();
                int res = mAudioManager.requestAudioFocus(audioFocusRequest);
                if (res == AudioManager.AUDIOFOCUS_REQUEST_FAILED) {
                    Log.d("TTSMEDIAPLAYER", "audio focus failed...");
                    return false;
                } else if (res == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
                    Log.d("TTSMEDIAPLAYER", "audio focus granted...");
                    return true;
                } else if (res == AudioManager.AUDIOFOCUS_REQUEST_DELAYED) {
                    Log.d("TTSMEDIAPLAYER", "audio focus DELAYED...");
                    // use case for this is imagine being in a phone call that has focus,
                    // then the user opens a game. The game
                    // should start playing audio once the call finishes.
                    return false; // todo?
                }
            }else{
                final int result = mAudioManager.requestAudioFocus(this,
                        AudioManager.STREAM_MUSIC,
                        AudioManager.AUDIOFOCUS_GAIN);
                return result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED;
            }
            Log.d("TTSMEDIAPLAYER", "audio focus returning default!?");
            return false;
        }

        private void abandonAudioFocus() {
            Log.d("TTSMEDIAPLAYER", "abandonAudioFocus()");
            mAudioManager.abandonAudioFocus(this);
        }

        @Override
        public void onAudioFocusChange(int focusChange) {
            Log.d("TTSMEDIAPLAYER", "Audio focus changed...");
            switch (focusChange) {
                case AudioManager.AUDIOFOCUS_GAIN:

                    Log.d("TTSMEDIAPLAYER", "Audio focus gained!");
                    if (mPlayOnAudioFocus && player.isPaused()) {
                        player.resume();
                        //} else if (isPlaying()) {
                        //    setVolume(MEDIA_VOLUME_DEFAULT);
                    }
                    mPlayOnAudioFocus = false;
                    break;

                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
                    Log.d("TTSMEDIAPLAYER", "Something about ducks!?");
                    // this might be for dropping the sound while something else happens (text notifications)
                    //setVolume(MEDIA_VOLUME_DUCK);
                    break;

                case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
                    Log.d("TTSMEDIAPLAYER", "AUDIOFOCUS_LOSS_TRANSIENT!");
                    if (player.isPlaying()) {
                        // I think this is for temporary loss of focus e.g. calls/notificaitons
                        mPlayOnAudioFocus = true;
                        player.pause();
                    }
                    break;
                case AudioManager.AUDIOFOCUS_LOSS:
                    // Seems to be triggered when you press play in another media app (i.e. they requested focus)
                    Log.d("TTSMEDIAPLAYER", "AUDIOFOCUS_LOSS! abandoning focus, pausing speech");
                    mAudioManager.abandonAudioFocus(this);
                    if (player.isPlaying()) {
                        player.pause();
                        mPlayOnAudioFocus = false;
                    }
                    updateNotificationAndMediaButtons(false);
                    break;
                default:
                    Log.d("TTSMEDIAPLAYER", "AUDIOFOCUS_???");
            }
        }
    }
}

build.gradle

dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'com.google.android.material:material:1.0.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'androidx.vectordrawable:vectordrawable:1.1.0'
implementation 'androidx.legacy:legacy-support-v13:1.0.0'
implementation 'androidx.legacy:legacy-support-v4:1.0.0'
implementation 'androidx.media:media:1.1.0'
...

我在这个问题上卡了一段时间，所以非常感谢任何帮助。

日志：

? I/MusicController: [MediaSessionMonitor.java:153:onActiveSessionsChanged()] oooooo 
? I/MusicController: [MediaSessionMonitor.java:302:clear()] oooooo 
? D/MusicController: [MediaSessionMonitor.java:99:clearMediaContorllersMap()] oooooo Controller is already empty
? W/MusicController: [MediaSessionMonitor.java:171:updateMediaControllers()] oooooo Controller is empty
? I/MediaFocusControl:  AudioFocus  requestAudioFocus() from uid/pid 10345/8858 clientId=android.media.AudioManagerEx@63b6ee9fishpowered.bar.services.TextToSpeechMediaControllerService$AudioFocusHelper@44f676e req=1 flags=0x0
? I/MusicController: [MediaSessionMonitor.java:153:onActiveSessionsChanged()] oooooo 
? I/MusicController: [MediaSessionMonitor.java:174:updateMediaControllers()] oooooo List size :1
? I/MusicController: [MediaSessionMonitor.java:178:updateMediaControllers()] oooooo MediaController received packageName foo.bar
? D/MusicController: [MediaSessionMonitor.java:74:addToMediaContorllersMap()] oooooo Added = android.media.session.MediaSession$Token@986e7dd
? I/MusicController: [MediaSessionMonitor.java:78:addToMediaContorllersMap()] oooooo mMediaContorllersMap.size() = 1
? I/MusicController: [MediaSessionMonitor.java:222:checkAndUpdateMusicController()] oooooo is MusicController Updated = false
? I/MusicController: [MediaSessionMonitor.java:182:updateMediaControllers()] oooooo mMediaContorllersMap size = 1
? I/MediaFocusControl:  AudioFocus  requestAudioFocus() from uid/pid 10345/8858 clientId=android.media.AudioManagerEx@63b6ee9fishpowered.bar.services.TextToSpeechMediaControllerService$AudioFocusHelper@44f676e req=1 flags=0x0
? I/MusicController: [MediaControllerCallbackWrapper.java:55:onMetadataChanged()] oooooo This callback is from foo.bar
? I/MusicController: [MediaControllerCallbackWrapper.java:47:onPlaybackStateChanged()] oooooo This callback is from foo.bar
? D/MusicController: [MediaSessionMonitor.java:123:handleMessage()] oooooo MediaSessionMonitor.MsgHandler msg = 2
? D/MusicController: [MediaSessionMonitor.java:205:checkAndUpdateMusicController()] oooooo state = 3, action = 585
? I/MusicController: [MediaSessionMonitor.java:234:isValidStateToRegister()] oooooo isValidStateToRegister = true
? I/MusicController: [MediaSessionMonitor.java:257:isValidMetadataToRegister()] oooooo isValidMetadataToRegister = true
? I/MusicController: [MediaSessionMonitor.java:245:isValidActionToRegister()] oooooo isValidActionToRegister = false
? I/MusicController: [MediaSessionMonitor.java:222:checkAndUpdateMusicController()] oooooo is MusicController Updated = false
? D/MusicController: [MediaSessionMonitor.java:123:handleMessage()] oooooo MediaSessionMonitor.MsgHandler msg = 1
? D/MusicController: [MediaSessionMonitor.java:205:checkAndUpdateMusicController()] oooooo state = 3, action = 585
? I/MusicController: [MediaSessionMonitor.java:234:isValidStateToRegister()] oooooo isValidStateToRegister = true
? I/MusicController: [MediaSessionMonitor.java:257:isValidMetadataToRegister()] oooooo isValidMetadataToRegister = true
? I/MusicController: [MediaSessionMonitor.java:245:isValidActionToRegister()] oooooo isValidActionToRegister = false
? I/MusicController: [MediaSessionMonitor.java:222:checkAndUpdateMusicController()] oooooo is MusicController Updated = false
? I/MusicController: [MediaControllerCallbackWrapper.java:47:onPlaybackStateChanged()] oooooo This callback is from foo.bar
? D/MusicController: [MediaSessionMonitor.java:123:handleMessage()] oooooo MediaSessionMonitor.MsgHandler msg = 1
? D/MusicController: [MediaSessionMonitor.java:205:checkAndUpdateMusicController()] oooooo state = 3, action = 585
? I/MusicController: [MediaSessionMonitor.java:234:isValidStateToRegister()] oooooo isValidStateToRegister = true
? I/MusicController: [MediaSessionMonitor.java:257:isValidMetadataToRegister()] oooooo isValidMetadataToRegister = true
? I/MusicController: [MediaSessionMonitor.java:245:isValidActionToRegister()] oooooo isValidActionToRegister = false
? I/MusicController: [MediaSessionMonitor.java:222:checkAndUpdateMusicController()] oooooo is MusicController Updated = false
? V/MediaRouter: Adding route: RouteInfo{ name=Phone, description=null, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO , presentationDisplay=null }
? V/MediaRouter: Adding route: RouteInfo{ name=DummyDevice, description=Bluetooth audio, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO , presentationDisplay=null }
? V/MediaRouter: Selecting route: RouteInfo{ name=DummyDevice, description=Bluetooth audio, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO , presentationDisplay=null }
? V/MediaRouter: Audio routes updated: AudioRoutesInfo{ type=SPEAKER, bluetoothName=DummyDevice }, a2dp=true
? W/MediaSessionCompat: Couldn't find a unique registered media button receiver in the given context.
? I/MusicController: [MediaSessionMonitor.java:153:onActiveSessionsChanged()] oooooo 
? I/MusicController: [MediaSessionMonitor.java:174:updateMediaControllers()] oooooo List size :1
? I/MusicController: [MediaSessionMonitor.java:178:updateMediaControllers()] oooooo MediaController received packageName foo.bar
? D/MusicController: [MediaSessionMonitor.java:76:addToMediaContorllersMap()] oooooo Already exist = android.media.session.MediaSession$Token@986e7dd
? I/MusicController: [MediaSessionMonitor.java:78:addToMediaContorllersMap()] oooooo mMediaContorllersMap.size() = 1
? D/MusicController: [MediaSessionMonitor.java:205:checkAndUpdateMusicController()] oooooo state = 3, action = 585
? I/MusicController: [MediaSessionMonitor.java:234:isValidStateToRegister()] oooooo isValidStateToRegister = true
? I/MusicController: [MediaSessionMonitor.java:257:isValidMetadataToRegister()] oooooo isValidMetadataToRegister = true
? I/MusicController: [MediaSessionMonitor.java:245:isValidActionToRegister()] oooooo isValidActionToRegister = false
? I/MusicController: [MediaSessionMonitor.java:222:checkAndUpdateMusicController()] oooooo is MusicController Updated = false
? I/MusicController: [MediaSessionMonitor.java:182:updateMediaControllers()] oooooo mMediaContorllersMap size = 1
? V/MediaRouter: Selecting route: RouteInfo{ name=DummyDevice, description=Bluetooth audio, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO , presentationDisplay=null }
? V/MediaRouter: Adding route: RouteInfo{ name=Phone, description=null, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO , presentationDisplay=null }
? V/MediaRouter: Adding route: RouteInfo{ name=DummyDevice, description=Bluetooth audio, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO , presentationDisplay=null }
? V/MediaRouter: Selecting route: RouteInfo{ name=DummyDevice, description=Bluetooth audio, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO , presentationDisplay=null }
? V/MediaRouter: Audio routes updated: AudioRoutesInfo{ type=SPEAKER, bluetoothName=DummyDevice }, a2dp=true
? V/MediaRouter: Selecting route: RouteInfo{ name=DummyDevice, description=Bluetooth audio, status=null, category=RouteCategory{ name=System types=ROUTE_TYPE_LIVE_AUDIO ROUTE_TYPE_LIVE_VIDEO  groupable=false }, supportedTypes=ROUTE_TYPE_LIVE_AUDIO , presentationDisplay=null }

我还发现了一个音频权限错误，但我不确定是否与此相关：

W/MediaListnrAuthObsrvr: registration failed - not an approved notification listener yet?
    java.lang.SecurityException: Missing permission to control media.
        at android.os.Parcel.readException(Parcel.java:1951)
        at android.os.Parcel.readException(Parcel.java:1897)
        at android.media.session.ISessionManager$Stub$Proxy.addSessionsListener(ISessionManager.java:342)
        at android.media.session.MediaSessionManager.addOnActiveSessionsChangedListener(MediaSessionManager.java:226)
        at android.media.session.MediaSessionManager.addOnActiveSessionsChangedListener(MediaSessionManager.java:189)
        at com.google.android.clockwork.common.media.DefaultMediaSessionManagerWrapper.addOnActiveSessionsChangedListener(AW771527612:8)
        at com.google.android.clockwork.companion.mediacontrols.api21.MediaSessionListenerAuthorizationObserver.register(AW771527612:12)
        at com.google.android.clockwork.companion.mediacontrols.api21.MediaSessionListenerAuthorizationObserver.<init>(AW771527612:5)
        at com.google.android.clockwork.companion.mediacontrols.api21.MediaRemoteControllerApi21.start(AW771527612:13)
有什么建议吗？提示？还有其他需要做的事情吗？这基本上是所有代码，除了MediaStyle通知，我还需要做些什么吗？包都没问题吧？还有什么可能会导致其他应用程序窃取KeyEvents吗？等等。 - MeatPopsicle
请检查我的答案。我认为它应该解决问题。 - Zaartha
3个回答
4

我最终发现为什么这对我没有起作用。似乎 Android Oreo 存在一个 bug，即使请求了焦点并使用 TTS 引擎播放音频，媒体焦点也无法正确获取。

解决方法是在开始 TTS 前从系统 Mediaplayer 播放一个静音的 wav 文件。

1
你有找到任何支持你的错误报告的资源吗？我和你遇到了同样的问题，但是我不认为这是一个SDK的Bug，因为有一些应用程序可以正确地处理这个流程。我还想过在onResume中播放空白音频文件以捕捉媒体按钮的焦点，但这绝对是一个hack，这表明我们做错了某些事情。 - Pedro Pedrosa
2
我没有找到任何官方的错误报告，只是另一个开发者提到了这个错误，并且声明可以通过在尝试播放TTS之前直接播放无声wav来解决所有问题。此外，如果我不使用TTS而使用内置的mediaplayer，则我的代码将正常工作，因此如果有更好的解决方法，我很乐意听取建议，但至少无声wav hack 对我有效。 - MeatPopsicle
非常感谢！我已经遇到类似的问题很长时间了，这就是解决方案！ - nverinaud
问题已经在这里向Google报告了：https://issuetracker.google.com/issues/249741615 - nverinaud
2

抱歉回复晚了，但或许对某些人有所帮助。 如果你正在使用 MediaSessionCompat 和 MediaSessionConnector，这是代码：

    mediaSessionConnector.setMediaButtonEventHandler(new MediaSessionConnector.MediaButtonEventHandler() {
        @NonNullApi
        @Override
        public boolean onMediaButtonEvent(Player player, Intent mediaButtonEvent) {
            KeyEvent dugme;
            if (Build.VERSION.SDK_INT >= 33) {
                dugme = mediaButtonEvent.getParcelableExtra(Intent.EXTRA_KEY_EVENT, KeyEvent.class);
            }else{
                dugme = mediaButtonEvent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
            }
            toast("command: "+dugme);
            return false;
        }
    });

需要记住的是，如果您想播放或停止媒体，则必须使用耳机上的 KeyCode KEYCODE_HEADSETHOOK 捕获按钮按下事件。

如果您只使用 MediaSessionCompat，则以下是代码：

    mediaSession.setCallback(new MediaSessionCompat.Callback() {
        @Override
        public boolean onMediaButtonEvent(Intent mediaButtonEvent) {
            KeyEvent dugme;
            if (Build.VERSION.SDK_INT >= 33) {
                dugme = mediaButtonEvent.getParcelableExtra(Intent.EXTRA_KEY_EVENT, KeyEvent.class);
            }else{
                dugme = mediaButtonEvent.getParcelableExtra(Intent.EXTRA_KEY_EVENT);
            }
            toast("command: "+dugme);
            return super.onMediaButtonEvent(mediaButtonEvent);
        }
    });

同样适用于从耳机捕获按钮按下的情况。 编程愉快。
2
如此处所述，您必须在PlaybackStateCompat.Builder上调用setActions()来准确告知您支持哪些操作 - 如果您不设置，则将无法获得与媒体按钮相关的任何回调。您正在回调中设置这些操作，这就是为什么它不起作用的原因。
....

private Handler handler;
private PlaybackStateCompat.Builder mStateBuilder;
.....

在onCreate方法中添加以下内容。
....
mediaSession = new MediaSessionCompat(this, "fpt2s");

mStateBuilder = new PlaybackStateCompat.Builder()
            .setActions(
                    PlaybackStateCompat.ACTION_PLAY |
                            PlaybackStateCompat.ACTION_PAUSE |
                            PlaybackStateCompat.ACTION_SKIP_TO_PREVIOUS |
                          PlaybackStateCompat.ACTION_SKIP_TO_NEXT |
                            PlaybackStateCompat.ACTION_PLAY_PAUSE);

mediaSession.setPlaybackState(mStateBuilder.build());
mediaSession.setCallback(callback);
mediaSession.setActive(true);

.......
抱歉，但我尝试了这个方法，它没有起作用。我的媒体按钮最初是可以使用的，但后来我尝试在手机上启动另一个媒体应用程序，然后再次从我的应用程序播放媒体。一旦其他媒体应用程序被打开（即使我关闭它们），它们就会窃取按键事件，例如，如果我正在播放我的媒体，然后按下手表上的暂停按钮，它会暂停，但只是因为它已经向其他应用程序发送了播放指令，导致我失去了音频焦点。我在日志中注意到了这一点： [MediaSessionMonitor.java:245:isValidActionToRegister()] oooooo isValidActionToRegister = false - MeatPopsicle
1
看起来你的想法是正确的，即动作并不总是被注册，因此它不允许触发回调。不幸的是，我的女朋友真的希望我帮忙打扫卫生，所以我稍后必须更多地进行实验。我会更新原始帖子，并附上一些日志。 - MeatPopsicle
我尝试了你在之前评论中提到的方法，对我来说很有效。清理代码？看起来你并不急着处理它，而且它并不需要你通过悬赏所想要的那种关注。希望你下次小心一些 :) - Zaartha
1
我已经卡在这个问题上几周了，尝试了无数种方法，所以你质疑我想悬赏解决它的愿望非常奇怪。我也尝试了你的答案，并在悬赏到期前发表了评论，那么你到底生气什么？我复制并粘贴了你的代码，并尝试了很多变化，但仍然没有解决问题。我还观看了视频，并花了几个小时研究，但毫无进展。例如，isValidActionToRegister始终显示为false，所以感谢你的帮助，但不幸的是它没有解决根本问题。 - MeatPopsicle
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