Kotlin.TypeCastException: null kann nicht auf Nicht-Null-Typ umgewandelt werden kotlin.Long

Question

Ich muss diesen Fehler wirklich schnell entfernen, also bitte helfen Sie mir.

Dieser Code ist der Code für SongsPlayingFragment & der Fehler sind unter Protokolle Abschnitt angegeben.

Ich versuche eine Music Player App zu erstellen. Immer wenn ich die App öffne & auf einen beliebigen Song klicken, öffnet sich der Spielbildschirm & dann App stürzt ab.

Das Protokoll gibt einen Tippfehler, den ich nicht verstehen kann.

Jede Hilfe ist willkommen

Code: -

 package com.vikanshu.echo.Fragments 


     import android.app.Activity 
     import android.content.Context 
     import android.media.AudioManager 
     import android.media.MediaPlayer 
     import android.net.Uri 
     import android.os.Bundle 
     import android.os.Handler 
     import android.support.v4.app.Fragment 
     import android.support.v7.widget.DialogTitle 
     import android.view.LayoutInflater 
     import android.view.View 
     import android.view.ViewGroup 
     import android.widget.ImageButton 
     import android.widget.SeekBar 
     import android.widget.TextView 
     import com.vikanshu.echo.CurrentSongHelper 
     import com.vikanshu.echo.R 
     import com.vikanshu.echo.SongsDataType 
     import kotlinx.android.synthetic.main.fragment_song_playing.* 
     import java.util.* 
     import java.util.concurrent.TimeUnit 

     class SongPlayingFragment : Fragment() { 

      var myActivity: Activity ?= null 
      var mediaPlayer: MediaPlayer ?= null 
      var songName: TextView ?= null 
      var artistName: TextView ?= null 
      var seekBar : SeekBar ?= null 
      var startTime: TextView ?= null 
      var stopTime: TextView ?= null 
      var playPause: ImageButton ?= null 
      var previousSong: ImageButton ?= null 
      var nextSong: ImageButton ?= null 
      var loopSong: ImageButton ?= null 
      var shuffleSongs: ImageButton ?= null 
      var currentSongHelperObject: CurrentSongHelper ?= null 
      var currentPosition: Int = 0 
      var fetchSongs: ArrayList<SongsDataType> ?= null 
      var updateSongTime = object : Runnable{ 
       override fun run() { 
        val getCurrent = mediaPlayer?.currentPosition 
        startTime?.setText(String.format("%d:%d", 

          TimeUnit.MILLISECONDS.toMinutes(getCurrent?.toLong() as Long), 
          TimeUnit.MILLISECONDS.toSeconds(getCurrent?.toLong() as Long) - 
            TimeUnit.MILLISECONDS.toSeconds(TimeUnit.MILLISECONDS.toMinutes(getCurrent?.toLong() as Long)) 
        )) 
       Handler().postDelayed(this,1000) 
       } 

      } 

      override fun onCreateView(inflater: LayoutInflater?, container: ViewGroup?, 
             savedInstanceState: Bundle?): View? { 
       var view = inflater!!.inflate(R.layout.fragment_song_playing, container, false) 
       songName = view?.findViewById(R.id.songName) 
       artistName = view?.findViewById(R.id.songArtist) 
       seekBar = view?.findViewById(R.id.seekBar) 
       startTime = view?.findViewById(R.id.startTime) 
       stopTime = view?.findViewById(R.id.endTime) 
       playPause = view?.findViewById(R.id.playPauseButton) 
       previousSong = view?.findViewById(R.id.playPreviousButton) 
       nextSong = view?.findViewById(R.id.playNextButton) 
       loopSong = view?.findViewById(R.id.loopButton) 
       shuffleSongs = view?.findViewById(R.id.shuffleButton) 


       return view 
      } 

      override fun onAttach(context: Context?) { 
       super.onAttach(context) 
       myActivity = context as Activity 
      } 

      override fun onAttach(activity: Activity?) { 
       super.onAttach(activity) 
       myActivity = activity 
      } 

      override fun onActivityCreated(savedInstanceState: Bundle?) { 
       super.onActivityCreated(savedInstanceState) 

       currentSongHelperObject = CurrentSongHelper() 
       currentSongHelperObject?.isPlaying = true 
       currentSongHelperObject?.isLoop = false 
       currentSongHelperObject?.isShuffle = false 

       var path: String ?= null 
       var _songTitle: String ?= null 
       var _songID: Long ?= null 
       var _songArtist: String ?= null 


       try { 
        path = arguments.getString("path") 
        _songArtist = arguments.getString("songArtist") 
        _songTitle = arguments.getString("songTitle") 
        _songID = arguments.getInt("songID").toLong() 
        currentSongHelperObject?.songPath = path 
        currentSongHelperObject?.songArtist = _songArtist 
        currentSongHelperObject?.songId = _songID 
        currentSongHelperObject?.songTitle = _songTitle 
        currentPosition =arguments.getInt("songPosition") 
        fetchSongs = arguments.getParcelableArrayList("songData") 
        currentSongHelperObject?.currentPosition = currentPosition 
        updateTextViews(currentSongHelperObject?.songTitle as String,currentSongHelperObject?.songArtist as String) 


       }catch (e: Exception){ 
        e.printStackTrace() 
       } 
       mediaPlayer = MediaPlayer() 
       mediaPlayer?.setAudioStreamType(AudioManager.STREAM_MUSIC) 
       try { 
        mediaPlayer?.setDataSource(myActivity,Uri.parse(path)) 
       }catch (e: Exception){ 
        e.printStackTrace() 
       } 
       mediaPlayer?.start() 
       processInformation(mediaPlayer as MediaPlayer) 
       if(currentSongHelperObject?.isPlaying as Boolean){ 
        playPause?.setBackgroundResource(R.drawable.pause_icon) 
       }else{ 
        playPause?.setBackgroundResource(R.drawable.play_icon) 
       } 
       mediaPlayer?.setOnCompletionListener { 
        onSongComplete() 
       } 
       clickHandler() 
      } 

      fun onSongComplete(){ 
       if(currentSongHelperObject?.isShuffle as Boolean){ 
        playNext("PlayShuffle") 
        currentSongHelperObject?.isPlaying = true 
       }else{ 
        if (currentSongHelperObject?.isLoop as Boolean){ 
         currentSongHelperObject?.isPlaying = true 
         var nextSong = fetchSongs?.get(currentPosition) 
         currentSongHelperObject?.songTitle = nextSong?.songTittle 
         currentSongHelperObject?.songPath = nextSong?.songData 
         currentSongHelperObject?.songId = nextSong?.songId as Long 
         currentSongHelperObject?.currentPosition = currentPosition 
         updateTextViews(currentSongHelperObject?.songTitle as String,currentSongHelperObject?.songArtist as String) 
         mediaPlayer?.reset() 
         try { 
          mediaPlayer?.setDataSource(myActivity,Uri.parse(currentSongHelperObject?.songPath)) 
          mediaPlayer?.prepare() 
          mediaPlayer?.start() 
          processInformation(mediaPlayer as MediaPlayer) 
         }catch (e: Exception){ 
          e.printStackTrace() 
         } 
        }else{ 
         playNext("playNextNormal") 
         currentSongHelperObject?.isPlaying = true 
        } 
       } 
      } 

      fun clickHandler() { 

       shuffleButton?.setOnClickListener({ 
        if(currentSongHelperObject?.isShuffle as Boolean){ 
         shuffleButton?.setBackgroundResource(R.drawable.shuffle_white_icon) 
         currentSongHelperObject?.isShuffle = false 
        }else{ 
         currentSongHelperObject?.isShuffle = true 
         currentSongHelperObject?.isLoop = false 
         shuffleSongs?.setBackgroundResource(R.drawable.shuffle_icon) 
         loopButton?.setBackgroundResource(R.drawable.loop_white_icon) 
        } 
       }) 
       loopButton?.setOnClickListener({ 
        if(currentSongHelperObject?.isLoop as Boolean) { 
         currentSongHelperObject?.isLoop = false 
         loopButton?.setBackgroundResource(R.drawable.loop_white_icon) 
        }else{ 
         currentSongHelperObject?.isLoop = true 
         currentSongHelperObject?.isLoop = false 
         loopButton?.setBackgroundResource(R.drawable.loop_icon) 
        } 
       }) 
       playPauseButton?.setOnClickListener({ 
        if(mediaPlayer?.isPlaying as Boolean){ 
         mediaPlayer?.pause() 
         currentSongHelperObject?.isPlaying = false 
         playPause?.setBackgroundResource(R.drawable.play_icon) 
        }else{ 
         mediaPlayer?.start() 
         currentSongHelperObject?.isPlaying = true 
         playPause?.setBackgroundResource(R.drawable.pause_icon) 
        } 
       }) 
       playNextButton?.setOnClickListener({ 

        currentSongHelperObject?.isPlaying = true 
        if(currentSongHelperObject?.isShuffle as Boolean){ 
         playNext("PlayShuffle") 
        }else{ 
         playNext("playNextNormal") 
        } 

       }) 
       playPreviousButton?.setOnClickListener({ 
        currentSongHelperObject?.isPlaying = true 
        if (currentSongHelperObject?.isLoop as Boolean) 
         loopButton?.setBackgroundResource(R.drawable.loop_white_icon) 
        playPrevious() 
       }) 
      } 

      fun playNext(check: String){ 

       if(check.equals("playNextNormal",true)){ 
        currentPosition = currentPosition + 1 
       }else if (check.equals("PlayShuffle",true)){ 
        var randonObject = Random() 
        var randomPosition = randonObject.nextInt(fetchSongs?.size?.plus(1) as Int) 
        currentPosition = randomPosition 
       } 
       if(currentPosition == fetchSongs?.size){ 
        currentPosition = 0 
       } 
       currentSongHelperObject?.isLoop = false 
       var nextSong = fetchSongs?.get(currentPosition) 
       currentSongHelperObject?.songTitle = nextSong?.songTittle 
       currentSongHelperObject?.songArtist = nextSong?.songArtist 
       currentSongHelperObject?.songPath = nextSong?.songData 
       currentSongHelperObject?.songId = nextSong?.songId as? Long 
       updateTextViews(currentSongHelperObject?.songTitle as String,currentSongHelperObject?.songArtist as String) 
       mediaPlayer?.reset() 
       try { 
        mediaPlayer?.setDataSource(myActivity,Uri.parse(currentSongHelperObject?.songPath)) 
        mediaPlayer?.prepare() 
        mediaPlayer?.start() 
        processInformation(mediaPlayer as MediaPlayer) 
       }catch (e: Exception){ 
        e.printStackTrace() 
       } 

      } 
      fun playPrevious(){ 
       currentPosition = currentPosition - 1 
       if(currentPosition == -1) 
        currentPosition = 0 
       if (currentSongHelperObject?.isPlaying as Boolean) 
        playPauseButton?.setBackgroundResource(R.drawable.pause_icon) 
       else 
        playPauseButton?.setBackgroundResource(R.drawable.play_icon) 
       currentSongHelperObject?.isLoop = false 
       val nextSong = fetchSongs?.get(currentPosition) 
       currentSongHelperObject?.songTitle = nextSong?.songTittle 
       currentSongHelperObject?.songArtist = nextSong?.songArtist 
       currentSongHelperObject?.currentPosition = currentPosition 
       currentSongHelperObject?.songId = nextSong?.songId as Long 
       updateTextViews(currentSongHelperObject?.songTitle as String,currentSongHelperObject?.songArtist as String) 
       mediaPlayer?.reset() 
       try { 
        mediaPlayer?.setDataSource(activity,Uri.parse(currentSongHelperObject?.songPath)) 
        mediaPlayer?.prepare() 
        mediaPlayer?.start() 
        processInformation(mediaPlayer as MediaPlayer) 
       }catch (e: Exception){ 
        e.printStackTrace() 
       } 
      } 
      fun updateTextViews(songTitle: String,songArtist: String){ 
       songTittle.setText(songTitle) 
       songArtistXYZ.setText(songArtist) 
      } 
      fun processInformation(mediaplayer: MediaPlayer){ 

       val finalTimeXYZ = mediaplayer.duration 
       val startTimeXYZ = mediaplayer.currentPosition 
       startTime?.setText(String.format("%d:%d", 
         TimeUnit.MILLISECONDS.toMinutes(startTimeXYZ?.toLong() as Long), 
         TimeUnit.MILLISECONDS.toSeconds(startTimeXYZ?.toLong() as Long) - 
           TimeUnit.MILLISECONDS.toSeconds(TimeUnit.MILLISECONDS.toMinutes(startTimeXYZ?.toLong() as Long)))) 
       endTime?.setText(String.format("%d:%d", 
         TimeUnit.MILLISECONDS.toMinutes(finalTimeXYZ?.toLong() as Long), 
         TimeUnit.MILLISECONDS.toSeconds(finalTimeXYZ?.toLong() as Long) - 
           TimeUnit.MILLISECONDS.toSeconds(TimeUnit.MILLISECONDS.toMinutes(finalTimeXYZ?.toLong() as Long)))) 
       seekBar?.setProgress(startTimeXYZ) 
       Handler().postDelayed(updateSongTime,1000) 
      } 

     } 

LOGS: -

11-10 02:10:27.941 2706-2721/com.vikanshu.echo E/libEGL: load_driver(/system/lib/egl/libGLES_emulation.so): dlopen failed: library "/system/lib/egl/libGLES_emulation.so" not found 
11-10 02:10:28.127 2706-2721/com.vikanshu.echo E/EGL_emulation: tid 2721: eglSurfaceAttrib(1174): error 0x3009 (EGL_BAD_MATCH) 
11-10 02:10:29.500 2706-2721/com.vikanshu.echo E/EGL_emulation: tid 2721: eglSurfaceAttrib(1174): error 0x3009 (EGL_BAD_MATCH) 
11-10 02:10:40.882 2706-2706/com.vikanshu.echo E/MediaPlayer: start called in state 1, mPlayer(0x0) 
11-10 02:10:40.883 2706-2706/com.vikanshu.echo E/MediaPlayer: error (-38, 0) 
11-10 02:10:40.883 2706-2706/com.vikanshu.echo E/MediaPlayer: Attempt to call getDuration in wrong state: mPlayer=0x0, mCurrentState=0 
11-10 02:10:40.912 2706-2706/com.vikanshu.echo E/MediaPlayer: Error (-38,0) 
11-10 02:10:40.914 2706-2706/com.vikanshu.echo E/AndroidRuntime: FATAL EXCEPTION: main 
                   Process: com.vikanshu.echo, PID: 2706 
                   kotlin.TypeCastException: null cannot be cast to non-null type kotlin.Long 
                    at com.vikanshu.echo.Fragments.SongPlayingFragment.playNext(SongPlayingFragment.kt:235) 
                    at com.vikanshu.echo.Fragments.SongPlayingFragment.onSongComplete(SongPlayingFragment.kt:160) 
                    at com.vikanshu.echo.Fragments.SongPlayingFragment$onActivityCreated$1.onCompletion(SongPlayingFragment.kt:132) 
                    at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:2943) 
                    at android.os.Handler.dispatchMessage(Handler.java:102) 
                    at android.os.Looper.loop(Looper.java:154) 
                    at android.app.ActivityThread.main(ActivityThread.java:6119) 
                    at java.lang.reflect.Method.invoke(Native Method) 
                    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

Answer 1

Sie bekommen diesen Fehler, da Sie versuchen, null zu Long werfen:

val x: Long? = null as Long 
// >>> Exception in thread "main" kotlin.TypeCastException: 
// >>> null cannot be cast to non-null type kotlin.Long 

es beheben Sie safe cast operator verwenden:

val x: Long? = null as? Long 
println(x) // >>> null 

Aber Sie besser ausrechnen würde, warum sind Sie null Wert bekommen.