なぜ私はこのエラー "java.lang.IllegalStateException"をメディアプレイヤーアンドロイドアプリ

Question

私はアンドロイド開発に新しいと現在私はアンドロイドメディアプレーヤー簡単なアプリケーションを開発しています。だから、私の質問は、なぜ私はこのexception.According私は3つの断片を定義している、最初の断片は、Mediaplayerコントロールを表示し、曲を再生するPlayerの断片です、2番目の断片は、曲リストを含むプレイリスト、最近再生された曲が入っている最近のプレイリストです。このプロジェクトでは、新しい曲を再生するためにプレイリストの断片アイテムをクリックしていて、突然この例外はjava.lang.IllegalStateExceptionを生成します。

ここにこれが私のプレーヤーの断片

package com.v1.sensoft.m_player.Fragment; 

import android.app.Activity; 
import android.app.AlertDialog; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.media.AudioManager; 
import android.media.MediaPlayer; 
import android.media.audiofx.Visualizer; 
import android.net.sip.SipSession; 
import android.os.Bundle; 
import android.os.Handler; 
import android.support.v4.app.Fragment; 
import android.support.v4.view.MotionEventCompat; 
import android.text.TextUtils; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.ImageButton; 
import android.widget.SeekBar; 
import android.widget.TextView; 
import android.widget.Toast; 

import com.v1.sensoft.m_player.Activity.AudioFxActivit; 
import com.v1.sensoft.m_player.Adapter.SongAdapter; 
import com.v1.sensoft.m_player.R; 
import com.v1.sensoft.m_player.Utility.SongsManager; 
import com.v1.sensoft.m_player.Utility.Utilities; 
import com.v1.sensoft.m_player.Visualizer.SliderView; 
import com.v1.sensoft.m_player.Visualizer.VisualizerView; 
import com.v1.sensoft.m_player.djView.ClickWheel; 
import com.v1.sensoft.m_player.djView.WheelModel; 
import com.v1.sensoft.m_player.model.SongModel; 

import java.io.IOException; 
import java.util.ArrayList; 
import java.util.Random; 


public class Player extends Fragment implements WheelModel.Listener,MediaPlayer.OnCompletionListener,SeekBar.OnSeekBarChangeListener { 

private ImageButton btnPlay; 
private ImageButton btnForward; 
private ImageButton btnBackward; 
private ImageButton btnNext; 
private ImageButton btnPrevious; 
private ImageButton btnRepeat; 
private ImageButton btnShuffle; 
private SeekBar songProgressBar; 
private TextView songTitleLabel; 
private TextView songCurrentDurationLabel; 
private TextView songTotalDurationLabel; 
// Media Player 
public static MediaPlayer mp,mp2; 
VisualizerView mVisualizerView; 
SliderView sl; 
private Visualizer mVisualizer; 
// Handler to update UI timer, progress bar etc,. 
private Handler mHandler = new Handler();; 
private SongsManager songManager; 
private Utilities utils; 
private int seekForwardTime = 5000; // 5000 milliseconds 
private int seekBackwardTime = 5000; // 5000 milliseconds 
private int currentSongIndex = 0; 
private boolean isShuffle = false; 
private boolean isRepeat = false; 
private ArrayList<SongModel> songsList = new ArrayList<SongModel>(); 
int songIndex; 
SongAdapter songAdapter; 
public Player(int position) { 
    songIndex = position; 
} 

public Player() { 

} 


    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 

    View android = inflater.inflate(R.layout.player, container, false); 

    ClickWheel wheel = (ClickWheel) android.findViewById(R.id.wheel); 
     wheel.getModel().addListener(this); 
    // variable initialization for button 
    btnPlay = (ImageButton) android.findViewById(R.id.btnPlay); 
    btnForward = (ImageButton) android.findViewById(R.id.btnForward); 
    btnBackward = (ImageButton) android.findViewById(R.id.btnBackward); 
    btnNext = (ImageButton) android.findViewById(R.id.btnNext); 
    btnPrevious = (ImageButton) android.findViewById(R.id.btnPrevious); 
    btnRepeat = (ImageButton) android.findViewById(R.id.btnRepeat); 
    btnShuffle = (ImageButton) android.findViewById(R.id.btnShuffle); 
    songProgressBar = (SeekBar) android.findViewById(R.id.songProgressBar); 
    songTitleLabel = (TextView) android.findViewById(R.id.songTitle); 
     songTitleLabel.setSelected(true); 
     songTitleLabel.setEllipsize(TextUtils.TruncateAt.MARQUEE); 
     songTitleLabel.setSingleLine(true); 
    songCurrentDurationLabel = (TextView)android.findViewById(R.id.songCurrentDurationLabel); 
    songTotalDurationLabel = (TextView) android.findViewById(R.id.songTotalDurationLabel); 
    // mVisualizerView = (VisualizerView) android.findViewById(R.id.myvisualizerview); 
    //audioManager = (AudioManager)getActivity().getSystemService(Context.AUDIO_SERVICE); 

    /* //sliding finger up and increase and decrease volume 
    android.setOnTouchListener(new View.OnTouchListener() { 
     public boolean onTouch(View v, MotionEvent event) { 
      int action = MotionEventCompat.getActionMasked(event); 
      if (action == MotionEvent.ACTION_MOVE) { 
       // put your volume change logic here, for example compare previously recorded x/y position to new one and change volume 
       audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, 5, 0); 
      } 
      return true; 
     } 
    });*/ 
    //Visualizer method 
    mp = new MediaPlayer(); 
    // initAudio(); 

    songManager = new SongsManager(); 
    utils = new Utilities(); 

    // Listeners 
    songProgressBar.setOnSeekBarChangeListener(this); // Important 
    mp.setOnCompletionListener(this); // Important 

    // Getting all songs list 
    songsList = songManager.getPlayList(); 
    // By default play first song 
    if (songIndex==0) 
    { 
     playSong(0); 
    } 
    else 
    { 
     playSong(songIndex); 
    } 
    btnPlay.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      // check for already playing 
      if (mp.isPlaying()) { 
       if (mp != null) { 
        mp.pause(); 
        btnPlay.setImageResource(R.drawable.btn_play); 
       } 
      } else { 
       // Resume song 
       if (mp != null) { 
        mp.start(); 
        btnPlay.setImageResource(R.drawable.btn_pause); 
       } 
      } 

     } 
    }); 
    btnForward.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      int currentPosition = mp.getCurrentPosition(); 
      if(currentPosition + seekForwardTime <= mp.getDuration()){ 
       mp.seekTo(currentPosition + seekForwardTime); 
      }else{ 
       mp.seekTo(mp.getDuration()); 
      } 
     } 
    }); 
    btnBackward.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      int currentPosition = mp.getCurrentPosition(); 
      if(currentPosition - seekBackwardTime >= 0){ 
       mp.seekTo(currentPosition - seekBackwardTime); 
      }else{ 
       mp.seekTo(0); 
      } 

     } 
    }); 
    btnNext.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      if(currentSongIndex < (songsList.size() - 1)){ 
       playSong(currentSongIndex + 1); 
       currentSongIndex = currentSongIndex + 1; 
      }else{ 
       playSong(0); 
       currentSongIndex = 0; 
      } 

     } 
    }); 
    btnPrevious.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      if(currentSongIndex > 0){ 
       playSong(currentSongIndex - 1); 
       currentSongIndex = currentSongIndex - 1; 
      }else{ 
       playSong(songsList.size() - 1); 
       currentSongIndex = songsList.size() - 1; 
      } 

     } 
    }); 
    btnRepeat.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      if(isRepeat){ 
       isRepeat = false; 
       Toast.makeText(getActivity().getApplicationContext(), "Repeat is OFF", Toast.LENGTH_SHORT).show(); 
       btnRepeat.setImageResource(R.drawable.btn_repeat); 
      }else{ 
       isRepeat = true; 
       Toast.makeText(getActivity().getApplicationContext(), "Repeat is ON", Toast.LENGTH_SHORT).show(); 
       isShuffle = false; 
       btnRepeat.setImageResource(R.drawable.btn_repeat_focused); 
       btnShuffle.setImageResource(R.drawable.btn_shuffle); 
      } 
     } 
    }); 
    btnShuffle.setOnClickListener(new View.OnClickListener() { 

     @Override 
     public void onClick(View arg0) { 
      if(isShuffle){ 
       isShuffle = false; 
       Toast.makeText(getActivity().getApplicationContext(), "Shuffle is OFF", Toast.LENGTH_SHORT).show(); 
       btnShuffle.setImageResource(R.drawable.btn_shuffle); 
      }else{ 
       isShuffle= true; 
       Toast.makeText(getActivity().getApplicationContext(), "Shuffle is ON", Toast.LENGTH_SHORT).show(); 
       isRepeat = false; 
       btnShuffle.setImageResource(R.drawable.btn_shuffle_focused); 
       btnRepeat.setImageResource(R.drawable.btn_repeat); 
      } 
     } 
    }); 
    return android; 

} 
public void playSong(int songIndex){ 
    try { 
     Log.e("playSong()...", "....is called"); 
     mp.reset(); 
     mp.setDataSource(songsList.get(songIndex).getSongPath()); 
     mp.prepare(); 
     songProgressBar.setProgress(0); 
     songProgressBar.setMax(100); 
     String songTitle = songsList.get(songIndex).getSongTitle(); 
     songTitleLabel.setText(songTitle); 
     btnPlay.setImageResource(R.drawable.btn_pause); 
     updateProgressBar(); 
     mp.start(); 
    } catch (IllegalArgumentException e) { 
     e.printStackTrace(); 
    } catch (IllegalStateException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
} 
@Override 
public void onActivityResult(int requestCode, int resultCode, Intent data) { 
    super.onActivityResult(requestCode, resultCode, data); 

    Log.i("song...songIndex...", "..." + songIndex); 

    mHandler.removeCallbacks(mUpdateTimeTask); 
    if(resultCode == 100){ 
     currentSongIndex = data.getExtras().getInt("songIndex"); 
     Log.i("song...currentSongIndex...", "..." + currentSongIndex); 
     // play selected song 
     playSong(currentSongIndex); 
    } 

} 
private Runnable mUpdateTimeTask = new Runnable() { 
    public void run() { 
     long totalDuration = mp.getDuration(); 
     long currentDuration = mp.getCurrentPosition(); 

     songTotalDurationLabel.setText(""+utils.milliSecondsToTimer(totalDuration)); 

     songCurrentDurationLabel.setText(""+utils.milliSecondsToTimer(currentDuration)); 

     int progress = (int)(utils.getProgressPercentage(currentDuration, totalDuration)); 

     songProgressBar.setProgress(progress); 

     mHandler.postDelayed(this,100); 
    } 
}; 
private void updateProgressBar() { 
    mHandler.postDelayed(mUpdateTimeTask,100); 
} 
@Override 
public void onCompletion(MediaPlayer mp) { 
    if(isRepeat){ 
     playSong(currentSongIndex); 
    } else if(isShuffle){ 
     Random rand = new Random(); 
     currentSongIndex = rand.nextInt((songsList.size() - 1) - 0 + 1) + 0; 
     playSong(currentSongIndex); 
    } else{ 
     if(currentSongIndex < (songsList.size() - 1)){ 
      playSong(currentSongIndex + 1); 
      currentSongIndex = currentSongIndex + 1; 
     }else{ 
      playSong(0); 
      currentSongIndex = 0; 
     } 
    } 
} 

@Override 
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 

} 

@Override 
public void onStartTrackingTouch(SeekBar seekBar) { 
    mHandler.removeCallbacks(mUpdateTimeTask); 
} 

@Override 
public void onStopTrackingTouch(SeekBar seekBar) { 
    mHandler.removeCallbacks(mUpdateTimeTask); 
    int totalDuration = mp.getDuration(); 
    int currentPosition = utils.progressToTimer(seekBar.getProgress(), totalDuration); 

    mp.seekTo(currentPosition); 
    updateProgressBar(); 
} 
@Override 
public void onDialPositionChanged(WheelModel sender, int nicksChanged) { 

    getActivity().setVolumeControlStream(AudioManager.STREAM_MUSIC); 
    mp2 =MediaPlayer.create(getActivity(),R.raw.djlazer); 
    mp2.start(); 
} 
@Override 
public void setUserVisibleHint(boolean isVisibleToUser) { 
    super.setUserVisibleHint(isVisibleToUser); 
    if (this.isVisible()) { 

     if (!isVisibleToUser) { 

     } 
    } 
} 
@Override 
public void onDestroy() { 
    super.onDestroy(); 
    mHandler.removeCallbacks(mUpdateTimeTask); 
    if(mp!=null) 
    { 
     if(mp.isPlaying()) mp.stop(); 
     mp.reset(); 
     mp.release(); 
    } 
} 
} 

プレイリスト断片です。

public class Playlists extends ListFragment { 


EditText edtSearch; 
SongAdapter songAdapter; 
ArrayList<SongModel> songList = new ArrayList<SongModel>(); 
SongsManager songsManager = new SongsManager(); 

// Songs list 
public ArrayList<SongModel> songsList = new ArrayList<>(); 
@Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 
    View windows = inflater.inflate(R.layout.playlist, container, false); 
    return windows; 
} 

@Override 
public void onViewCreated(View v, Bundle savedInstanceState) { 
    super.onViewCreated(v, savedInstanceState); 

    getListView().setFastScrollEnabled(true); 
    //ListView animation 
    LayoutAnimationController controller 
      = AnimationUtils.loadLayoutAnimation(
      getActivity(), R.anim.list_layout_controller); 
    getListView().setLayoutAnimation(controller); 
    edtSearch = (EditText)getView().findViewById(R.id.search); 
    final ArrayList<SongModel> songsListData = songsManager.songList; 
    Log.i("songsListData...",""+songsListData.size()); 
    SongsManager plm = new SongsManager(); 

    // get all songs from sdcard 
    this.songsList = plm.getPlayList(); 
    // looping through playlist 
    for (int i = 0; i < songsListData.size(); i++) { 
     // creating new HashMap 
     SongModel song = songsListData.get(i); 
     // adding HashList to ArrayList 
     songsListData.add(song); 
    } 

    songAdapter = new SongAdapter(getActivity(),songsList); 
    setListAdapter(songAdapter); 
    // selecting single ListView item 
    ListView lv = getListView(); 

    // listening to single listitem click 
    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() { 

     @Override 
     public void onItemClick(AdapterView<?> parent, View arg0, 
           int position, long id) { 

      Log.i("Index", "..." + position); 
      songAdapter.setSelectedIndex(position); 
      Intent i = new Intent(getActivity().getApplicationContext(),Main.class); 
      i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK|Intent.FLAG_ACTIVITY_NEW_TASK); 
      SongModel songModel = (SongModel) songAdapter.getItem(position); 
      int indexOfSong = songAdapter.songsList.indexOf(songModel); 

      // Sending songIndex to PlayerActivity 
      i.putExtra("songIndex", indexOfSong); 

      startActivityForResult(i, 100); 


      //putting song in recentSongList arraylist 
      SongModel model = (SongModel) songAdapter.getItem(position); 
      model.setSongTitle(songModel.getSongTitle()); 
      model.setSongPath(songModel.getSongPath()); 
      Constant.recentSongList.add(model); 
      Log.i("recentSongList...","..."+Constant.recentSongList.size()); 
      getActivity().finish(); 
     } 
    }); 
    lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { 
     @Override 
     public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { 

      removeItemFromList(position); 
      return true; 
     } 

     private void removeItemFromList(int position) { 

      final int deletePosition = position; 

      AlertDialog.Builder alert = new AlertDialog.Builder(
        getActivity()); 

      alert.setTitle("Delete"); 
      alert.setMessage("Do you want delete this song?"); 
      alert.setPositiveButton("YES", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        // TOD O Auto-generated method stub 

        // main code on after clicking yes 
        songsList.remove(deletePosition); 
        songAdapter.notifyDataSetChanged(); 
        songAdapter.notifyDataSetInvalidated(); 

       } 
      }); 
      alert.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        // TODO Auto-generated method stub 
        dialog.dismiss(); 
       } 
      }); 

      alert.show(); 
     } 
    }); 
    edtSearch.addTextChangedListener(new TextWatcher() { 
     @Override 
     public void beforeTextChanged(CharSequence s, int start, int count, int after) { 

     } 

     @Override 
     public void onTextChanged(CharSequence cs, int start, int before, int count) { 

     } 

     @Override 
     public void afterTextChanged(Editable s) { 
      String text = edtSearch.getText().toString().toLowerCase(Locale.getDefault()); 
      songAdapter.filter(text); 
     } 
    }); 
} 
@Override 
public void setUserVisibleHint(boolean isVisibleToUser) { 
    super.setUserVisibleHint(isVisibleToUser); 

    if (this.isVisible()) { 
     // If we are becoming invisible, then... 
     Log.d("setUserVisibleHint()...", "PlayList...Visible"); 
     if (!isVisibleToUser) { 
      Log.d("setUserVisibleHint()...", "PlayList...notVisible"); 
      // TODO stop audio playback 
     } 
    } 
} 

そして、これが私のlogcatので

09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime: FATAL EXCEPTION: main 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime: Process: com.v1.sensoft.m_player, PID: 17474 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime: java.lang.IllegalStateException 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at android.media.MediaPlayer.getDuration(Native Method) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at com.v1.sensoft.m_player.Fragment.Player$8.run(Player.java:289) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at android.os.Handler.handleCallback(Handler.java:808) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:103) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:193) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:5333) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at java.lang.reflect.Method.invokeNative(Native Method) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Method.java:515) 
09-14 18:43:12.052 17474-17474/com.v1.sensoft.m_player E/AndroidRuntime:  atcom.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:824) 

で、どのように私は任意の助けてください、問題が何であるかを知っているこのproblem.Ifを解決することができます。 ありがとうございます...

Answer 1

あなたが間違った状態でMediaPlayer.getDuration()を呼び出すようだMediaPlayerはIdle、InitializedまたはError状態にあるとき、the official document about MediaPlayerによると、MediaPlayer.getDuration()方法を呼び出すことはできません。

MediaPlayerで開発する場合は、MediaPlayerの状態をよく考慮する必要があります。

Answer 2

アンドロイドメディアプレーヤーには多くの問題があります。 メディアプレーヤーがアイドル状態のときにメソッドを呼び出すことはできません。

Official Documents のようになります。

さらに、newを使用して作成されたMediaPlayerオブジェクトは、アイドル状態にありますが、オーバーロードされた便利な作成メソッドの1つで作成されたものは、アイドル状態ではありません。実際、createメソッドを使用した作成が成功した場合、オブジェクトはPrepared状態になります。

使用

MediaPlayer mediaPlayer = MediaPlayer.create(this, Uri.parse("uriString")); 

あなたは自由にお使い始めることができるように、すでに、（）メソッドを用意呼び出しています。 うまくいくことを願っています。