getting context is nullpoint exception even though tried many solutions in service

Question

I'm trying to get context in service. I know that Service extends Context and I can get it at onCreate method. So I tried it and got error. I don't understand other example uses the context at onCreate and works, but not to me. Also I registered my service. the error is occurred at this line in service.

player = ExoPlayerFactory.newSimpleInstance(mContext, DefaultTrackSelector())

Why the context is null even though I initialized the context in onCreate? I saw the similar problem at here Android getContext on a background Service

error

java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference

activity

 override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)


        val musicPlayer = binding.musicPlayer
  
        musicPlayer.player = audioService.getplayerInstance()
        musicPlayer.player.playWhenReady = true
        mIntent = Intent(this,AudioService::class.java)
        Util.startForegroundService(this,mIntent)
        bindService(mIntent, mConnection, Context.BIND_AUTO_CREATE);
        initializePlayer();


    }

Service


class AudioService  : Service() {
    private val mBinder: IBinder =Binder()
    private var player: SimpleExoPlayer? = null
    private var playerNotificationManager: PlayerNotificationManager? = null
    private var cacheDataSourceFactory : CacheDataSourceFactory?=null
    var mContext: Context? = null
    override fun onDestroy() {
        releasePlayer()
        super.onDestroy()
    }

    override fun onCreate() {
        super.onCreate()
        mContext = this
        if (player == null) {
            startPlayer()
        }
    }

    private fun releasePlayer() {
        if (player != null) {
            playerNotificationManager!!.setPlayer(null)
            player!!.release()
            player = null
        }
    }

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

    fun getplayerInstance(): SimpleExoPlayer? {
        if (player == null) {
            startPlayer()
        }
        return player
    }

    override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
        return START_STICKY
    }

    private fun startPlayer() {

        val uri: Uri = Uri.parse("https://storage.googleapis.com/exoplayer-test-media-0/Jazz_In_Paris.mp3")
        player = ExoPlayerFactory.newSimpleInstance(mContext, DefaultTrackSelector())

        cacheDataSourceFactory = getCacheDataSourceFactory(mContext!!)
        val mediaSource: MediaSource = ProgressiveMediaSource.Factory(cacheDataSourceFactory)
            .createMediaSource(uri)
        player!!.prepare(mediaSource)
        player!!.setPlayWhenReady(true)


        playerNotificationManager = PlayerNotificationManager.createWithNotificationChannel(
            mContext,"channel_id", com.haii.exoplayerdemo.R.string.channelName,com.haii.exoplayerdemo.R.string.channelDescription,11,
            object : PlayerNotificationManager.MediaDescriptionAdapter{
                override fun createCurrentContentIntent(player: Player): PendingIntent? {
                    val intent = Intent(mContext,MainActivity::class.java)
                    return PendingIntent.getActivity(mContext,0,intent,PendingIntent.FLAG_UPDATE_CURRENT)
                }

                override fun getCurrentContentText(player: Player): String? {
                    return "description"
                }

                override fun getCurrentContentTitle(player: Player): String {
                    return "title"
                }

                override fun getCurrentLargeIcon(
                    player: Player,
                    callback: PlayerNotificationManager.BitmapCallback
                ): Bitmap? {
                    return null
                }

            } ,
            object : PlayerNotificationManager.NotificationListener {
                override fun onNotificationStarted(notificationId: Int, notification: Notification) {
                    Log.d("TAG","onNotificationStarted")
                    startForeground(notificationId,notification)
                }
                override fun onNotificationPosted(notificationId: Int, notification: Notification, ongoing: Boolean) {
                    Log.d("TAG","onNotificationPosted")
//                    startForeground(notificationId,notification)
                }

                override fun onNotificationCancelled(notificationId: Int, dismissedByUser: Boolean) {
                    Log.e("TAG","onNotificationCancelled 2")
                    stopSelf()
                }

                override fun onNotificationCancelled(notificationId: Int) {
                    Log.e("TAG","onNotificationCancelled 1")
//                    stopSelf()
                }
            }
        )
        playerNotificationManager!!.setPlayer(player)
    }

    fun getCacheDataSourceFactory(context : Context) : com.haii.exoplayerdemo.CacheDataSourceFactory?{
        if(cacheDataSourceFactory==null){
            cacheDataSourceFactory = com.haii.exoplayerdemo.CacheDataSourceFactory(
                context,
                DefaultDataSourceFactory(context, "ua"),
                MyExoPlayer.MAX_CACHE_VALUE, MyExoPlayer.MAX_CACHE_FILE_VALUE
            )
        }
        return cacheDataSourceFactory
    }


}

score 0 · Answer 1 · answered Aug 12 '20 at 06:25

I`m refering from here https://developer.android.com/guide/components/services.

The thing that you are doing wrong is calling getPlayerInstance() before onCreate is called. Your oncreate is called when you either bind or start the service. Good luck

getting context is nullpoint exception even though tried many solutions in service

1 Answers1