Entwicklerwarnung für Paket, Benachrichtigung bei Kanal null fehlgeschlagen. Weitere Informationen finden Sie im Protokoll. Toast Nachricht

Question

Ich wurde mein MP3-Player gemacht.

es funktioniert, aber ich habe immer einen Toast Nachricht

eingeben Bild Beschreibung hier

so denke ich, dass ich in meinem Code Benachrichtigungskanal benötigen.

aber ich weiß nicht, wie man Code hinzufügt. Hilf mir !!

hier ist mein Code

public class MusicController extends MediaController { 

public MusicController(Context c){ 
    super(c); 
} 

public void hide(){} 
} 

public class MusicService extends Service implements 
    MediaPlayer.OnPreparedListener, MediaPlayer.OnErrorListener, 
    MediaPlayer.OnCompletionListener { 

//media player 
private MediaPlayer player; 
//song list 
private ArrayList<Song> songs; 
//current position 
private int songPosn; 
//binder 
private final IBinder musicBind = new MusicBinder(); 
//title of current song 
private String songTitle=""; 
//notification id 
private static final int NOTIFY_ID=1; 
//shuffle flag and random 
private boolean shuffle=false; 
private Random rand; 

public void onCreate(){ 
    //create the service 
    super.onCreate(); 
    //initialize position 
    songPosn=0; 
    //random 
    rand=new Random(); 
    //create player 
    player = new MediaPlayer(); 
    //initialize 
    initMusicPlayer(); 
} 

public void initMusicPlayer(){ 
    //set player properties 
    player.setWakeMode(getApplicationContext(), 
      PowerManager.PARTIAL_WAKE_LOCK); 
    player.setAudioStreamType(AudioManager.STREAM_MUSIC); 
    //set listeners 
    player.setOnPreparedListener(this); 
    player.setOnCompletionListener(this); 
    player.setOnErrorListener(this); 
} 

//pass song list 
public void setList(ArrayList<Song> theSongs){ 
    songs=theSongs; 
} 

//binder 
public class MusicBinder extends Binder { 
    MusicService getService() { 
     return MusicService.this; 
    } 
} 

//activity will bind to service 
@Override 
public IBinder onBind(Intent intent) { 
    return musicBind; 
} 

//release resources when unbind 
@Override 
public boolean onUnbind(Intent intent){ 
    player.stop(); 
    player.release(); 
    return false; 
} 

//play a song 
public void playSong(){ 
    //play 
    player.reset(); 
    //get song 
    Song playSong = songs.get(songPosn); 
    //get title 
    songTitle=playSong.getTitle(); 
    //get id 
    long currSong = playSong.getID(); 
    //set uri 
    Uri trackUri = ContentUris.withAppendedId(
      android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, 
      currSong); 
    //set the data source 
    try{ 
     player.setDataSource(getApplicationContext(), trackUri); 
    } 
    catch(Exception e){ 
     Log.e("MUSIC SERVICE", "Error setting data source", e); 
    } 
    player.prepareAsync(); 
} 

//set the song 
public void setSong(int songIndex){ 
    songPosn=songIndex; 
} 

@Override 
public void onCompletion(MediaPlayer mp) { 
    //check if playback has reached the end of a track 
    if(player.getCurrentPosition()>0){ 
     mp.reset(); 
     playNext(); 
    } 
} 

@Override 
public boolean onError(MediaPlayer mp, int what, int extra) { 
    Log.v("MUSIC PLAYER", "Playback Error"); 
    mp.reset(); 
    return false; 
} 

@Override 
public void onPrepared(MediaPlayer mp) { 
    //start playback 
    mp.start(); 
    //notification 
    Intent notIntent = new Intent(this, MainActivity.class); 
    notIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); 
    PendingIntent pendInt = PendingIntent.getActivity(this, 0, 
      notIntent, PendingIntent.FLAG_UPDATE_CURRENT); 

    Notification.Builder builder = new Notification.Builder(this); 

    builder.setContentIntent(pendInt) 
      .setSmallIcon(R.drawable.android_music_player_play) 
      .setTicker(songTitle) 
      .setOngoing(true) 
      .setContentTitle("Playing") 
      .setContentText(songTitle); 
    Notification not = builder.build(); 
    startForeground(NOTIFY_ID, not); 
} 

//playback methods 
public int getPosn(){ 
    return player.getCurrentPosition(); 
} 

public int getDur(){ 
    return player.getDuration(); 
} 

public boolean isPng(){ 
    return player.isPlaying(); 
} 

public void pausePlayer(){ 
    player.pause(); 
} 

public void seek(int posn){ 
    player.seekTo(posn); 
} 

public void go(){ 
    player.start(); 
} 

//skip to previous track 
public void playPrev(){ 
    songPosn--; 
    if(songPosn<0) songPosn=songs.size()-1; 
    playSong(); 
} 

//skip to next 
public void playNext(){ 
    if(shuffle){ 
     int newSong = songPosn; 
     while(newSong==songPosn){ 
      newSong=rand.nextInt(songs.size()); 
     } 
     songPosn=newSong; 
    } 
    else{ 
     songPosn++; 
     if(songPosn>=songs.size()) songPosn=0; 
    } 
    playSong(); 
} 

@Override 
public void onDestroy() { 
    stopForeground(true); 
} 

//toggle shuffle 
public void setShuffle(){ 
    if(shuffle) shuffle=false; 
    else shuffle=true; 
} 

} 

public class MainActivity extends Activity implements MediaPlayerControl { 

//song list variables 
private ArrayList<Song> songList; 
private ListView songView; 

//service 
private MusicService musicSrv; 
private Intent playIntent; 
//binding 
private boolean musicBound=false; 

//controller 
private MusicController controller; 

//activity and playback pause flags 
private boolean paused=false, playbackPaused=false; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) { 
     if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) 
       != PackageManager.PERMISSION_GRANTED) { 

      requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},1); 


      return; 
     }} 

    //retrieve list view 
    songView = (ListView)findViewById(R.id.song_list); 
    //instantiate list 
    songList = new ArrayList<Song>(); 
    //get songs from device 
    getSongList(); 
    //sort alphabetically by title 
    Collections.sort(songList, new Comparator<Song>(){ 
     public int compare(Song a, Song b){ 
      return a.getTitle().compareTo(b.getTitle()); 
     } 
    }); 
    //create and set adapter 
    SongAdapter songAdt = new SongAdapter(this, songList); 
    songView.setAdapter(songAdt); 

    //setup controller 
    setController(); 
} 

//connect to the service 
private ServiceConnection musicConnection = new ServiceConnection(){ 

    @Override 
    public void onServiceConnected(ComponentName name, IBinder service) { 
     MusicBinder binder = (MusicBinder)service; 
     //get service 
     musicSrv = binder.getService(); 
     //pass list 
     musicSrv.setList(songList); 
     musicBound = true; 
    } 

    @Override 
    public void onServiceDisconnected(ComponentName name) { 
     musicBound = false; 
    } 
}; 

//start and bind the service when the activity starts 
@Override 
protected void onStart() { 
    super.onStart(); 
    if(playIntent==null){ 
     playIntent = new Intent(this, MusicService.class); 
     bindService(playIntent, musicConnection, Context.BIND_AUTO_CREATE); 
     startService(playIntent); 
    } 
} 

//user song select 
public void songPicked(View view){ 
    musicSrv.setSong(Integer.parseInt(view.getTag().toString())); 
    musicSrv.playSong(); 
    if(playbackPaused){ 
     setController(); 
     playbackPaused=false; 
    } 
    controller.show(0); 
} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    // Inflate the menu; this adds items to the action bar if it is present. 
    getMenuInflater().inflate(R.menu.main, menu); 
    return true; 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    //menu item selected 
    switch (item.getItemId()) { 
     case R.id.action_shuffle: 
      musicSrv.setShuffle(); 
      break; 
     case R.id.action_end: 
      stopService(playIntent); 
      musicSrv=null; 
      System.exit(0); 
      break; 
    } 
    return super.onOptionsItemSelected(item); 
} 

//method to retrieve song info from device 
public void getSongList(){ 
    //query external audio 
    ContentResolver musicResolver = getContentResolver(); 
    Uri musicUri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; 
    Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null); 
    //iterate over results if valid 
    if(musicCursor!=null && musicCursor.moveToFirst()){ 
     //get columns 
     int titleColumn = musicCursor.getColumnIndex 
       (android.provider.MediaStore.Audio.Media.TITLE); 
     int idColumn = musicCursor.getColumnIndex 
       (android.provider.MediaStore.Audio.Media._ID); 
     int artistColumn = musicCursor.getColumnIndex 
       (android.provider.MediaStore.Audio.Media.ARTIST); 
     //add songs to list 
     do { 
      long thisId = musicCursor.getLong(idColumn); 
      String thisTitle = musicCursor.getString(titleColumn); 
      String thisArtist = musicCursor.getString(artistColumn); 
      songList.add(new Song(thisId, thisTitle, thisArtist)); 
     } 
     while (musicCursor.moveToNext()); 
    } 
} 

@Override 
public boolean canPause() { 
    return true; 
} 

@Override 
public boolean canSeekBackward() { 
    return true; 
} 

@Override 
public boolean canSeekForward() { 
    return true; 
} 

@Override 
public int getAudioSessionId() { 
    return 0; 
} 

@Override 
public int getBufferPercentage() { 
    return 0; 
} 

@Override 
public int getCurrentPosition() { 
    if(musicSrv!=null && musicBound && musicSrv.isPng()) 
     return musicSrv.getPosn(); 
    else return 0; 
} 

@Override 
public int getDuration() { 
    if(musicSrv!=null && musicBound && musicSrv.isPng()) 
     return musicSrv.getDur(); 
    else return 0; 
} 

@Override 
public boolean isPlaying() { 
    if(musicSrv!=null && musicBound) 
     return musicSrv.isPng(); 
    return false; 
} 

@Override 
public void pause() { 
    playbackPaused=true; 
    musicSrv.pausePlayer(); 
} 

@Override 
public void seekTo(int pos) { 
    musicSrv.seek(pos); 
} 

@Override 
public void start() { 
    musicSrv.go(); 
} 

//set the controller up 
private void setController(){ 
    controller = new MusicController(this); 
    //set previous and next button listeners 
    controller.setPrevNextListeners(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      playNext(); 
     } 
    }, new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      playPrev(); 
     } 
    }); 
    //set and show 
    controller.setMediaPlayer(this); 
    controller.setAnchorView(findViewById(R.id.song_list)); 
    controller.setEnabled(true); 
} 

private void playNext(){ 
    musicSrv.playNext(); 
    if(playbackPaused){ 
     setController(); 
     playbackPaused=false; 
    } 
    controller.show(0); 
} 

private void playPrev(){ 
    musicSrv.playPrev(); 
    if(playbackPaused){ 
     setController(); 
     playbackPaused=false; 
    } 
    controller.show(0); 
} 

@Override 
protected void onPause(){ 
    super.onPause(); 
    paused=true; 
} 

@Override 
protected void onResume(){ 
    super.onResume(); 
    if(paused){ 
     setController(); 
     paused=false; 
    } 
} 

@Override 
protected void onStop() { 
    controller.hide(); 
    super.onStop(); 
} 

@Override 
protected void onDestroy() { 
    stopService(playIntent); 
    musicSrv=null; 
    super.onDestroy(); 
    } 
} 

, wie ich es beheben kann? ! Hilf mir !

Answer 1

Per der Migration MediaStyle notifications to support Android O blog post:

Um Meldungen in O zu verwenden, müssen Sie notification channels verwenden.

Wenn Sie API 26 oder höher als Ziel haben, müssen Sie allen Benachrichtigungen einen Benachrichtigungskanal hinzufügen. Der Blogpost durchläuft die vorgeschlagenen Einstellungen, die Sie für Medienbenachrichtigungen verwenden sollten.