流媒体在线音频 - 播放第一个音频仅

Question

我有两个活动：

1. MediaPlayer_Activity（显示像播放，暂停，停止，下一控制....）
2. MediaPlayerPlayList_Acitivty（显示所有可用的歌曲）

我通过加载的所有歌曲URL流一上线音频文件中的ArrayList称为SongsList和播放一个由一个或用户可以从MediaPlayerPlayList_Acitivty（不同的活动，显示所有的选择歌曲）并播放任何歌曲... MediaPlayerPlayList_Acitivty传递正确的songIndex，并通过调试代码进行确认。

问题：它只播放第一首是songIndex（0）的歌曲，而不管我从MediaPlayerPlayList_Acitivty中选择哪首歌曲，它会播放第一首歌曲。

一旦我从MediaPlayerPlayList_Acitivty中选择了一首新歌曲，我就会得到我在下面粘贴的错误信息，同时粘贴了我用于此媒体播放器的核心代码。

我花了很多时间调试代码，但没有效果。

的logcat：

03-18 07:15:52.338: E/MediaPlayer(998): error (1, -1004) 
    03-18 07:15:52.338: W/System.err(998): java.io.IOException: Prepare failed.: status=0x1 
    03-18 07:15:52.338: W/System.err(998): at android.media.MediaPlayer.prepare(Native Method) 
    03-18 07:15:52.338: W/System.err(998): at net.website.player.MediaPlayer_Activity.playSong(MediaPlayer_Activity.java:341) 
    03-18 07:15:52.338: W/System.err(998): at net.website.player.MediaPlayer_Activity.onActivityResult(MediaPlayer_Activity.java:325) 
    03-18 07:15:52.338: W/System.err(998): at android.app.Activity.dispatchActivityResult(Activity.java:3908) 
    03-18 07:15:52.338: W/System.err(998): at android.app.ActivityThread.deliverResults(ActivityThread.java:2528) 
    03-18 07:15:52.338: W/System.err(998): at android.app.ActivityThread.handleSendResult(ActivityThread.java:2574) 
    03-18 07:15:52.338: W/System.err(998): at android.app.ActivityThread.access$2000(ActivityThread.java:117) 
    03-18 07:15:52.338: W/System.err(998): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:961) 
    03-18 07:15:52.348: W/System.err(998): at android.os.Handler.dispatchMessage(Handler.java:99) 
    03-18 07:15:52.348: W/System.err(998): at android.os.Looper.loop(Looper.java:123) 
    03-18 07:15:52.348: W/System.err(998): at android.app.ActivityThread.main(ActivityThread.java:3683) 
    03-18 07:15:52.348: W/System.err(998): at java.lang.reflect.Method.invokeNative(Native Method) 
    03-18 07:15:52.348: W/System.err(998): at java.lang.reflect.Method.invoke(Method.java:507) 
    03-18 07:15:52.348: W/System.err(998): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
    03-18 07:15:52.348: W/System.err(998): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
    03-18 07:15:52.348: W/System.err(998): at dalvik.system.NativeStart.main(Native Method) 
    03-18 07:15:52.348: E/MediaPlayer(998): Attempt to call getDuration without a valid mediaplayer 
    03-18 07:15:52.348: E/MediaPlayer(998): error (-38, 0) 
    03-18 07:15:52.458: E/MediaPlayer(998): Error (-38,0) 
    03-18 07:15:52.458: D/onCompletion(998): 2 
    03-18 07:15:52.458: D/playSong(998): 5 
    03-18 07:15:53.058: E/MediaPlayer(998): error (1, -1004) 
    03-18 07:15:53.058: W/System.err(998): java.io.IOException: Prepare failed.: status=0x1 
    03-18 07:15:53.058: W/System.err(998): at android.media.MediaPlayer.prepare(Native Method) 
    03-18 07:15:53.058: W/System.err(998): at net.website.player.MediaPlayer_Activity.playSong(MediaPlayer_Activity.java:341) 
    03-18 07:15:53.058: W/System.err(998): at net.website.player.MediaPlayer_Activity.onCompletion(MediaPlayer_Activity.java:449) 
    03-18 07:15:53.058: W/System.err(998): at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:1344) 
    03-18 07:15:53.058: W/System.err(998): at android.os.Handler.dispatchMessage(Handler.java:99) 
    03-18 07:15:53.058: W/System.err(998): at android.os.Looper.loop(Looper.java:123) 
    03-18 07:15:53.058: W/System.err(998): at android.app.ActivityThread.main(ActivityThread.java:3683) 
    03-18 07:15:53.058: W/System.err(998): at java.lang.reflect.Method.invokeNative(Native Method) 
    03-18 07:15:53.058: W/System.err(998): at java.lang.reflect.Method.invoke(Method.java:507) 
    03-18 07:15:53.058: W/System.err(998): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
    03-18 07:15:53.058: W/System.err(998): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
    03-18 07:15:53.068: W/System.err(998): at dalvik.system.NativeStart.main(Native Method) 
    03-18 07:15:53.218: E/MediaPlayer(998): Attempt to call getDuration without a valid mediaplayer 
    03-18 07:15:53.218: E/MediaPlayer(998): error (-38, 0) 
    03-18 07:15:53.218: E/MediaPlayer(998): Error (-38,0) 
    03-18 07:15:53.218: D/onCompletion(998): 3 
    03-18 07:15:53.228: D/playSong(998): 5 
    03-18 07:15:53.828: E/MediaPlayer(998): error (1, -1004) 
    03-18 07:15:53.828: W/System.err(998): java.io.IOException: Prepare failed.: status=0x1 
    03-18 07:15:53.828: W/System.err(998): at android.media.MediaPlayer.prepare(Native Method) 
    03-18 07:15:53.828: W/System.err(998): at net.website.player.MediaPlayer_Activity.playSong(MediaPlayer_Activity.java:341) 
    03-18 07:15:53.828: W/System.err(998): at net.website.player.MediaPlayer_Activity.onCompletion(MediaPlayer_Activity.java:449) 
    03-18 07:15:53.828: W/System.err(998): at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:1344) 
    03-18 07:15:53.828: W/System.err(998): at android.os.Handler.dispatchMessage(Handler.java:99) 
    03-18 07:15:53.828: W/System.err(998): at android.os.Looper.loop(Looper.java:123) 
    03-18 07:15:53.828: W/System.err(998): at android.app.ActivityThread.main(ActivityThread.java:3683) 
    03-18 07:15:53.828: W/System.err(998): at java.lang.reflect.Method.invokeNative(Native Method) 
    03-18 07:15:53.828: W/System.err(998): at java.lang.reflect.Method.invoke(Method.java:507) 
    03-18 07:15:53.828: W/System.err(998): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
    03-18 07:15:53.828: W/System.err(998): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
    03-18 07:15:53.828: W/System.err(998): at dalvik.system.NativeStart.main(Native Method) 
    03-18 07:15:53.908: E/MediaPlayer(998): Attempt to call getDuration without a valid mediaplayer 
    03-18 07:15:53.908: E/MediaPlayer(998): error (-38, 0) 
    03-18 07:15:53.918: E/MediaPlayer(998): Error (-38,0) 

代码：

public void onCreate(Bundle savedInstanceState) { 
// Mediaplayer 
mp = new MediaPlayer(); 
mp.setOnCompletionListener(this); 

mp.setOnPreparedListener(new OnPreparedListener() { 
public void onPrepared(MediaPlayer mp) { 
    Log.d("onPrepared", "mp.start()"); 
    mp.start(); 
    } 
}); 
} 

public void onCompletion(MediaPlayer arg0) { 
     Log.d("onCompletion", ""+currentSongIndex); 
     // check for repeat is ON or OFF 
     if(isRepeat){ 
      // repeat is on play same song again 
      playSong(currentSongIndex); 
     } else if(isShuffle){ 
      // shuffle is on - play a random song 
      Random rand = new Random(); 
      currentSongIndex = rand.nextInt((songsList.size() - 1) - 0 + 1) + 0; 
      playSong(currentSongIndex); 
     } else{ 
      // no repeat or shuffle ON - play next song 
      if(currentSongIndex < (songsList.size() - 1)){ 
       playSong(currentSongIndex + 1); 
       currentSongIndex = currentSongIndex + 1; 
      }else{ 
       // play first song 
       playSong(0); 
       currentSongIndex = 0; 
      } 
     } 
    } 

public void playSong(int songIndex){ 
      // Play song 
      //mp.setAudioStreamType(AudioManager.STREAM_MUSIC); 
      try { 
       Log.d("playSong", ""+ songsList.size()); 
       mp.reset(); 
       mp.setDataSource(songsList.get(songIndex).get("audio_url")); 
       mp.prepare(); 
       //mp.start(); // 
       // Displaying Song title 
       String songTitle = songsList.get(songIndex).get("title_a"); 
       songTitleLabel.setText(songTitle); 

       // Changing Button Image to pause image 
       btnPlay.setImageResource(R.drawable.btn_pause); 

       // set Progress bar values 
       songProgressBar.setProgress(0); 
       songProgressBar.setMax(100); 

       // Updating progress bar 
       updateProgressBar();  

      } catch (IllegalArgumentException e) { 
       e.printStackTrace(); 
      } catch (IllegalStateException e) { 
       e.printStackTrace(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } 
     } 

Answer 1

从堆栈跟踪看来，准备调用由于java.io.IOException而失败。数据源url是否正确？ songsList列表可能没有正确填充？

Answer 2

看来，您的应用程序因为 mp.getDuration()呼叫崩溃。我的猜测是，这是发生在你的 updateProgressBar()方法，当它在不合时宜的执行。

既然你在playSong方法注册一个OnCompletionListener，你应该叫prepareAsync()代替prepare()。

编辑看着堆栈跟踪接近，看来问题不是从updateProgressBar()内发生，而是直接从呼叫prepare()内playSong()。看看是否切换到prepareAsync()会改变行为。