Android MediaSessionCompat 回调未触发

问题描述

我正在创建一个有声读物播放器，我正在使用与 MediaSessionCompat 相关的类来处理通知。我的代码很大程度上受到了 android-MediabrowserService 示例 ( https://github.com/googlearchive/android-MediaBrowserService ) 的启发，我暂时还不是很理解（尤其是 createContentIntent ）

这是我的简单类，负责从提供元数据和播放状态数据的 bookPlayer 构建通知

class Playernotificationmanager(val playerService: PlayerService) {

    val CHANNEL_ID = "pylvain.gamma"
    val NOTIFICATION_ID = 412
    private val REQUEST_CODE = 501

    val notificationmanager =
        playerService.getSystemService(Context.NOTIFICATION_SERVICE) as notificationmanager

    private val playAction: NotificationCompat.Action =
        NotificationCompat.Action (
            android.R.drawable.ic_media_pause,"PAUSE",buildMediaButtonPendingIntent(
                playerService,PlaybackStateCompat.ACTION_PAUSE
            )
        )

    fun getNotification(bookPlayer: BookPlayer): Notification  {

        if (isAndroidOOrHigher()) createChannel()

        val style = androidx.media.app.NotificationCompat.MediaStyle()
            .setMediaSession(playerService.sessionToken)
            .setShowCancelButton(true)
            .setShowActionsInCompactView(0)
            .setCancelButtonIntent(
                buildMediaButtonPendingIntent(
                    playerService,PlaybackStateCompat.ACTION_STOP
                )
            )

        val builder = NotificationCompat.Builder(playerService,CHANNEL_ID)
            .addAction(playAction)
            .setStyle(style)
            .setSmallIcon(R.drawable.ic_music_rest_quarter)
            .setContentIntent(createContentIntent())
            .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)

        return builder.build()

    }

    private fun createContentIntent(): PendingIntent { //Todo: Understand that
        Timber.i("Creating Intent")
        val openUI = Intent(playerService,MainActivity::class.java)
        openUI.flags = Intent.FLAG_ACTIVITY_SINGLE_TOP
        return PendingIntent.getActivity(
            playerService,openUI,PendingIntent.FLAG_UPDATE_CURRENT
        )
    }

通知显示与元数据完美结合

这是我的 MediabrowserService 处理媒体会话，我在其中注册了回调。 bookplayer 是用 Koin 构建和注入的。 :

class PlayerService : MediabrowserServiceCompat() {

    private lateinit var playernotificationmanager: Playernotificationmanager
    lateinit var session: MediaSessionCompat

    private val bookPlayer: BookPlayer by inject()

    override fun onCreate() {
        super.onCreate()

        session = MediaSessionCompat(this,"MusicService")
        session.apply {
            setFlags(
                MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS or
                        MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS
            )
            setPlaybackState(bookPlayer.playbackState)
            setMetadata(bookPlayer.getMetadata())
            setCallback(callbacks)
            setActive(true)
        }

        setSessionToken(session.sessionToken)
        playernotificationmanager = Playernotificationmanager(this)

        val notification = playernotificationmanager.getNotification(bookPlayer)

        startForeground(playernotificationmanager.NOTIFICATION_ID,notification)

    }

    override fun onTaskRemoved(rootIntent: Intent?) { //Todo
        super.onTaskRemoved(rootIntent)
        stopSelf()
    }

    override fun onStartCommand(intent: Intent?,flags: Int,startId: Int): Int {
        return super.onStartCommand(intent,flags,startId)
    }

    override fun onGetRoot(
        clientPackageName: String,clientUid: Int,rootHints: Bundle?
    ): browserRoot? {
        return browserRoot("root",null)
    }

    override fun onLoadChildren(
        parentId: String,result: Result<MutableList<MediabrowserCompat.MediaItem>>
    ) {
        result.sendResult(null);
    }
    
    override fun onDestroy() {
        session.release()
    }


    val callbacks = object : MediaSessionCompat.Callback() {

        override fun onCommand(command: String?,extras: Bundle?,cb: ResultReceiver?) {
            Timber.i("Test")
            super.onCommand(command,extras,cb)
        }

        override fun onPrepare() {
            Timber.i("Preparing")
        }

        override fun onPlay() {
            Timber.i("Playing")
            bookPlayer.pause()
        }

        override fun onPause() {
            Timber.i("Pausing")
            bookPlayer.pause()
        }

        override fun onSkipToNext() {}
        override fun onSkipToPrevIoUs() {}
        override fun onStop() {}
        override fun onSeekTo(pos: Long) {}
        override fun onMediaButtonEvent(mediaButtonIntent: Intent): Boolean = true

    }

}

然后服务从主activity启动

startService(Intent(mainContext,PlayerService::class.java))

我也将此添加到我的 Android 清单中

        <service android:name=".playerservice.PlayerService">
            <intent-filter>
                <action android:name="android.media.browse.MediabrowserService" />
            </intent-filter>
        </service>


        <receiver android:name="androidx.media.session.MediaButtonReceiver">
            <intent-filter>
                <action android:name="android.intent.action.MEDIA_BUTTON" />
            </intent-filter>
        </receiver>

每当我按下按钮时都不会调用任何回调。当我这样做时，应用程序会记录以下文本：

D/MediabrowserCompat: Connecting to a MediabrowserService.

什么也没发生... 我已经搜索了整个互联网，但我完全一无所知，但这肯定很简单。有人能帮我吗 ？预先非常感谢您

解决方法

回调有效......只是不是预期的方式。原来是播放动作按钮在调用

override fun onMediaButtonEvent(mediaButtonIntent: Intent): Boolean = true

我删除了这个函数，然后......它有效......

感谢您的关注！

,

如果你想获得媒体按钮，你必须播放一些东西。 尝试在您的服务启动时播放虚拟音频

    // play dummy audio
    AudioTrack at = new AudioTrack(AudioManager.STREAM_MUSIC,48000,AudioFormat.CHANNEL_OUT_STEREO,AudioFormat.ENCODING_PCM_16BIT,AudioTrack.getMinBufferSize(48000,AudioFormat.ENCODING_PCM_16BIT),AudioTrack.MODE_STREAM);
    at.play();

    // a little sleep 
    at.stop();
    at.release();

https://stackoverflow.com/a/50678833/9891730 - 这是我之前的回答