android 通知不显示action icon

Question

使用下面代码显示一个关于音乐播放器的通知。 通知有显示出来，但是使用addAction添加的三个icon看不到。
哪位指点一下，感谢！

private fun createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(
                WidgetMainActivity.CHANNEL_ID,
                "Music Service Channel",
                NotificationManager.IMPORTANCE_HIGH
            )
            channel.description = "Channel for music service notifications"
            val manager = getSystemService(NotificationManager::class.java)
            manager.createNotificationChannel(channel)
        }
    }

private fun initMediaSession(){
    mediaSession = MediaSessionCompat(this, "MusicService")
    mediaSession!!.isActive = true

    val metadata = MediaMetadataCompat.Builder()
        .putString(MediaMetadataCompat.METADATA_KEY_TITLE, "Music Title")
        .putString(MediaMetadataCompat.METADATA_KEY_ARTIST, "Artist Name")
        .putBitmap(MediaMetadataCompat.METADATA_KEY_ALBUM_ART,
            BitmapFactory.decodeResource(resources, R.drawable.music))
        .putLong(MediaMetadataCompat.METADATA_KEY_DURATION, 30000)
        .build()
    mediaSession!!.setMetadata(metadata)

    val playbackState = PlaybackStateCompat.Builder()
        .setState(PlaybackStateCompat.STATE_PLAYING, PlaybackStateCompat.PLAYBACK_POSITION_UNKNOWN,
            1.0f, SystemClock.elapsedRealtime())
        .build()
    mediaSession!!.setPlaybackState(playbackState)
}

fun mediaNotification() {
    val previousIntent = Intent(this, NotificationReceiver::class.java)
        .setAction(WidgetMainActivity.ACTION_PREVIOUS)
    val pendingPreviousIntent = PendingIntent.getBroadcast(this,
        0,
        previousIntent,
        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE)

    val playPauseIntent = Intent(this, NotificationReceiver::class.java)
        .setAction(WidgetMainActivity.ACTION_PLAY_PAUSE)
    val pendingPlayPauseIntent = PendingIntent.getBroadcast(this,
        0,
        playPauseIntent,
        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE)

    val nextIntent = Intent(this, NotificationReceiver::class.java)
        .setAction(WidgetMainActivity.ACTION_NEXT)
    val pendingNextIntent = PendingIntent.getBroadcast(this,
        0,
        nextIntent,
        PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE)

    val builder: NotificationCompat.Builder = NotificationCompat.Builder(this, WidgetMainActivity.CHANNEL_ID)
        .setSmallIcon(R.mipmap.ic_launcher)
        .setStyle(androidx.media.app.NotificationCompat.MediaStyle()
            .setShowActionsInCompactView(0, 1, 2)
            .setMediaSession(mediaSession!!.sessionToken)) 
        .addAction(android.R.drawable.ic_media_previous, "Previous", pendingPreviousIntent) 
        .addAction(android.R.drawable.ic_media_pause, "Pause", pendingPlayPauseIntent) 
        .addAction(android.R.drawable.ic_media_next, "Next", pendingNextIntent)
        .setVisibility(NotificationCompat.VISIBILITY_PUBLIC)
        .setPriority(NotificationCompat.PRIORITY_MAX)
    val notificationManager = NotificationManagerCompat.from(this)
    notificationManager.notify(WidgetMainActivity.NOTIFICATION_ID, builder.build())
}

Answer 1

解决了，用法错了。
应该是在PlaybackStateCompat.Builder 中使用setAction添加控制，NotificationCompat.Builder中的addAction不需要。
修改代码如下：

private fun createNotificationChannel() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(
                WidgetMainActivity.CHANNEL_ID,
                "Music Service Channel",
                NotificationManager.IMPORTANCE_HIGH
            ).apply {
                description = "Channel for music service notifications"
            }
            getSystemService(NotificationManager::class.java)
                .apply {
                    createNotificationChannel(channel)
                }
        }
    }

    private fun initMediaSession() {
        // 更新MediaSession的元数据
        val metadata = MediaMetadataCompat.Builder()
            .apply {
                putString(MediaMetadataCompat.METADATA_KEY_TITLE, "Music Title")
                putString(MediaMetadataCompat.METADATA_KEY_ARTIST, "Artist Name")
                putBitmap(MediaMetadataCompat.METADATA_KEY_ALBUM_ART,
                    BitmapFactory.decodeResource(resources, R.drawable.music))
                putLong(MediaMetadataCompat.METADATA_KEY_DURATION, 30000)
            }
            .build()

        val playbackState = PlaybackStateCompat.Builder()
            .apply {
                setState(PlaybackStateCompat.STATE_PLAYING, PlaybackStateCompat.PLAYBACK_POSITION_UNKNOWN,
                    1.0f, SystemClock.elapsedRealtime())
                setActions(PlaybackStateCompat.ACTION_PLAY
                        or PlaybackStateCompat.ACTION_PAUSE
                        or PlaybackStateCompat.ACTION_SKIP_TO_NEXT
                        or PlaybackStateCompat.ACTION_SKIP_TO_PREVIOUS)
            }
            .build()

        mediaSession = MediaSessionCompat(this, "MusicService").apply {
            isActive = true
            setMetadata(metadata)
            setPlaybackState(playbackState)
            setCallback(object : MediaSessionCompat.Callback() {
                override fun onPlay() {
                    super.onPlay()
                    Log.d("TAG", "onPlay")
                }

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

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

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

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

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

    fun mediaNotification() {
        val builder: NotificationCompat.Builder = NotificationCompat.Builder(this, WidgetMainActivity.CHANNEL_ID)
            .apply {
                setSmallIcon(R.mipmap.ic_launcher)
                setStyle(androidx.media.app.NotificationCompat.MediaStyle()
                    .setMediaSession(mediaSession!!.sessionToken)) // 需要MediaSession.Token
                setVisibility(NotificationCompat.VISIBILITY_PUBLIC) // 设置通知的隐私级别
                setPriority(NotificationCompat.PRIORITY_MAX)
            }

        val notificationManager = NotificationManagerCompat.from(this)
        notificationManager.notify(WidgetMainActivity.NOTIFICATION_ID, builder.build())
    }