没有来自 MediaSessionCompat.Callback() 的回调

Question

我一直在不知疲倦地盯着 android 提供的文档

MediaButtonReceiver 类 (https://developer.android.com/reference/kotlin/androidx/media/session/MediaButtonReceiver?hl=en)

以及响应媒体按钮的指南

(https://developer.android.com/guide/topics/media-apps/mediabuttons).

还查看了 StackOverflow 中遇到类似问题并遵循人们提供的指南的人，但我仍然没有找到解决此问题的方法。

Receiving media key events in Service

我想做的是让我的服务从蓝牙遥控器的音量调低/调高和播放按钮中获取事件。检查 sytem_process 日志时，我可以看到按钮事件确实被发送到服务，但回调没有收到任何这些事件。有什么线索吗？ Log.d 永远不会在回调中调用

AndroidManifest.xml

    <application
        android:name=".BaseApplication"
        android:allowBackup="true"
        android:debuggable="true"
        android:extractNativeLibs="false"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="HardcodedDebugMode">

        <activity
            android:name=".activity.MainActivity"
            android:screenOrientation="reverseLandscape">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <receiver
            android:name=".receivers.OnBootReceiver"
            android:enabled="true"
            android:exported="true"
            android:permission="android.permission.RECEIVE_BOOT_COMPLETED">
            <intent-filter android:priority="999">
                <action android:name="android.intent.action.BOOT_COMPLETED" />
                <action android:name="android.intent.action.QUICKBOOT_POWERON" />
            </intent-filter>
        </receiver>

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

        <service android:name=".service.MyForegroundService">
            <intent-filter>
                <action android:name="android.intent.action.MEDIA_BUTTON" />
            </intent-filter>
            <intent-filter>
                <action android:name="com.example.example.myservice.ACTION_BIND" />
            </intent-filter>
        </service>

    </application>

</manifest>

MyService.kt

class MyForegroundService : Service() {
    private val TAG = "MyForegroundService"

    private lateinit var mediaSession: MediaSessionCompat

    private fun getVolumeProvider(): VolumeProviderCompat? {
        val audio: AudioManager = getSystemService(AUDIO_SERVICE) as AudioManager
        val STREAM_TYPE: Int = AudioManager.STREAM_MUSIC
        val currentVolume: Int = audio.getStreamVolume(STREAM_TYPE)
        val maxVolume: Int = audio.getStreamMaxVolume(STREAM_TYPE)
        val VOLUME_UP = 1
        val VOLUME_DOWN = -1
        return object : VolumeProviderCompat(
            VOLUME_CONTROL_RELATIVE,
            maxVolume,
            currentVolume
        ) {
            override fun onAdjustVolume(direction: Int) {
                Log.d(TAG, "onAdjustVolume: ")
                // Up = 1, Down = -1, Release = 0
                // Replace with your action, if you don't want to adjust system volume
                if (direction == VOLUME_UP) {
                    audio.adjustStreamVolume(
                        STREAM_TYPE,
                        AudioManager.ADJUST_RAISE, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE
                    )
                } else if (direction == VOLUME_DOWN) {
                    audio.adjustStreamVolume(
                        STREAM_TYPE,
                        AudioManager.ADJUST_LOWER, AudioManager.FLAG_REMOVE_SOUND_AND_VIBRATE
                    )
                }
                setCurrentVolume(audio.getStreamVolume(STREAM_TYPE))
            }
        }
    }

     private val callback = object : MediaSessionCompat.Callback() {
        override fun onMediaButtonEvent(mediaButtonIntent: Intent): Boolean {
            val keyEvent = mediaButtonIntent.extras?.get(Intent.EXTRA_KEY_EVENT)
            Log.d(TAG, "onMediaButtonEvent: $keyEvent")
            return super.onMediaButtonEvent(mediaButtonIntent)
        }

        override fun onPlay() {
            Log.d(TAG, "onPlay: ")
            super.onPlay()
        }

        override fun onCommand(command: String?, extras: Bundle?, cb: ResultReceiver?) {
            Log.d(TAG, "onCommand: ")
            super.onCommand(command, extras, cb)
        }
    }

    override fun onCreate() {
        super.onCreate()
        mediaSession = MediaSessionCompat(applicationContext, "MyForegroundService")
        mediaSession.setFlags(
            MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS or
                    MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS
        )
        mediaSession.setPlaybackToRemote(getVolumeProvider())
        mediaSession.setCallback(callback)
        mediaSession.setActive(true)

    }

    override fun onBind(intent: Intent?): IBinder? {
        return binder
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        MediaButtonReceiver.handleIntent(mediaSession, intent)
        return START_STICKY
    }

    private fun startForeground() {
        // ...
        startForeground(1, notification)
    }

    override fun onDestroy() {
        super.onDestroy()
        mediaSession.release()
        stopForeground(true)
    }
}

Answer 1

您是否像这样注册了您的接收器：

IntentFilter filter = new IntentFilter(Intent.ACTION_MEDIA_BUTTON);
MediaButtonIntentReceiver r = new MediaButtonIntentReceiver();
filter.setPriority(1000); 
registerReceiver(r, filter); 

看这个例子：https://stackoverflow.com/a/38290944/11543864

而且我认为您的 xml 中服务中的接收器将无法正常工作。 该服务仅用于保持您的应用程序，然后您可以接收/收听不同的事件。