目前，我需要一个绑定（音乐）服务，因为我需要与之交互。但我也希望它不会被停止，即使所有组件都已解除绑定。
我的服务代码：
class ServicePlayer : LifecycleService() {
var mediaPlayer: MediaPlayer? = null
var notificationManager: NotificationManager? = null
var notificationBuilder: NotificationCompat.Builder? = null
private val mBinder: IBinder = PlayerBinder()
private val NOTIFICATION_ID = 1111
override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
super.onStartCommand(intent, flags, startId)
return START_REDELIVER_INTENT
}
inner class PlayerBinder : Binder() {
val service: ServicePlayer
get() = this@ServicePlayer
}
override fun onBind(intent: Intent): IBinder? {
super.onBind(intent)
return mBinder
}
override fun onCreate() {
super.onCreate()
mediaPlayer = MediaPlayer()
mediaPlayer!!.setOnCompletionListener(this)
mediaPlayer!!.setOnBufferingUpdateListener(this)
mediaPlayer!!.setOnErrorListener(this)
val filter = IntentFilter()
filter.addAction(TelephonyManager.ACTION_PHONE_STATE_CHANGED)
filter.addAction(Intent.ACTION_SCREEN_ON)
registerReceiver(receiver, filter)
}
override fun onDestroy() {
super.onDestroy()
mediaPlayer!!.reset()
mediaPlayer!!.release()
Log.i("DESTROY SERVICE", "destroy")
unregisterReceiver(receiver)
}
fun play(trackIndex: Int, tracks: ArrayList<Track>?) {
...
val intent = Intent(BUFFERING)
this@ServicePlayer.sendBroadcast(intent)
}
fun pause() {
if (mediaPlayer!!.isPlaying) {
mediaPlayer!!.pause()
PlayerLiveData.isPlaying.value = false
val intent = Intent(UPDATE_UI)
this@ServicePlayer.sendBroadcast(intent)
//Show notification
CoroutineScope(Dispatchers.Default).launch {
showNotification()
}
}
}
private fun hideNotification() {
notificationManager!!.cancel(NOTIFICATION_ID)
stopForeground(true)
}
private fun showNotification() {
notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
...
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
val CHANNEL_ID = "controls_channel_id"
val CHANNEL_NAME = "Play tracks"
val channel = NotificationChannel(CHANNEL_ID,CHANNEL_NAME, NotificationManager.IMPORTANCE_LOW)
...
val mMediaSession = MediaSessionCompat(applicationContext, getString(R.string.app_name))
mMediaSession.setFlags(
MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS or
MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS
)
notificationManager!!.createNotificationChannel(channel)
notificationBuilder = NotificationCompat.Builder(applicationContext)
.setChannelId(CHANNEL_ID)
.setContentText(artistText)
.setContentTitle(track.title)
...
} else {
notificationBuilder = NotificationCompat.Builder(applicationContext)
...
notificationBuilder!!
.setSmallIcon(R.drawable.ic_notification)
.setContentIntent(contentIntent)
.setCustomContentView(remoteSmallViews)
.setCustomBigContentView(remoteViews)
}
CoroutineScope(Dispatchers.Default).launch {
val notification = notificationBuilder!!.build()
startForeground(NOTIFICATION_ID, notification)
val notificationTarget = NotificationTarget(
applicationContext
, R.id.imgThumb, remoteViews
, notification, NOTIFICATION_ID
)
...
lifecycleScope.launch {
val request = ImageRequest.Builder(applicationContext)
.data(thumb)
.error(R.drawable.placeholder_song)
.placeholder(R.drawable.placeholder_song)
.build()
val drawable = imageLoader.execute(request).drawable
val bitmap = (drawable as BitmapDrawable).bitmap
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
notificationBuilder!!.setLargeIcon(bitmap)
val notification = notificationBuilder!!.build()
notificationManager!!.notify(NOTIFICATION_ID,notification)
//Start Foreground service
startForeground(NOTIFICATION_ID, notification)
}
}
}
}
}
清单文件声明：
<service android:name=".services.ServicePlayer" android:enabled="true" android:exported="true"/>
在活动中使用服务
class MainActivity : AppCompatActivity() {
lateinit var binding: MainActivityBinding
private lateinit var audioPlayerService: ServicePlayer
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
val intent = Intent(this, ServicePlayer::class.java)
bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE)
binding = DataBindingUtil.setContentView(this, R.layout.main_activity)
binding.lifecycleOwner = this
binding.viewmodel = mainViewModel
}
private val serviceConnection: ServiceConnection = object : ServiceConnection {
override fun onServiceDisconnected(name: ComponentName) {
// audioPlayerService = null;
}
override fun onServiceConnected(name: ComponentName, service: IBinder) {
audioPlayerService = (service as ServicePlayer.PlayerBinder).service
if (audioPlayerService.trackIndex !== -1) {
//updatePlaybackUI()
}
}
}
}
即使在活动被破坏后，我怎样才能让我的服务在后台运行。我参考了 StackOverflow 的几个线程，但它们没有帮助。
答案 0 :(得分：0)
使用 Service 而不是 LifecycleService 作为父类。
分别向 onCreate 和 onDestroy 方法添加部分唤醒锁启动和停止调用。
private val powerManager
get() = (this.getSystemService(Context.POWER_SERVICE) as PowerManager)
private var wakeLock: PowerManager.WakeLock? = null
private fun startWakeLock() {
if (wakeLock == null) {
wakeLock = powerManager.newWakeLock(
PowerManager.PARTIAL_WAKE_LOCK,
"${packageName}:wakeLock"
)
wakeLock?.acquire()
}
}
private fun stopWakeLock() {
if (wakeLock?.isHeld == true) {
wakeLock?.release()
wakeLock = null
}
}
在 mainfest 服务中添加以下标签
android:foregroundServiceType="mediaPlayback"
答案 1 :(得分：0)
一旦每个客户端解除绑定，绑定服务就会停止，并且 that happens automatically 当客户端（您的 Activity）被销毁时
如果您的应用程序销毁客户端时您的客户端仍绑定到服务，则销毁会导致客户端解除绑定。最好在与客户端交互完成后立即解除绑定客户端服务。这样做可以关闭空闲服务。
如果您希望服务继续运行，Started Service 可以做到这一点。您仍然可以绑定到它，但它不会停止，除非您明确告诉它停止并且没有绑定客户端。
老实说，如果您正在制作某种媒体播放器，您可能需要使用 MediaBrowserServiceCompat 框架。它允许您创建一个与 MediaBrowser（它进行绑定等）配合良好的服务，并允许您使用 MediaSession 来获取带有控件的媒体通知等等。
关于这些东西的一些链接：
如果您不关心其中任何一个，那么 startService/startForegroundService（或 ContextCompat#startForegroundService）将为您提供一个刚刚运行的服务，但这些链接可能会给您一些提示关于东西