异步任务中的MediaPlayer :未发布就完成了

Question

我编写了一个异步任务，用于播放幻灯片的BGM，在开始和暂停时淡入和淡出。当幻灯片活动开始播放幻灯片时，我启动任务和BGM，只有在幻灯片活动暂停时才取消任务。

比赛一开始就进行一段时间，突然停下来，回到赛道的起点。这项任务甚至没有被取消。我看到了这个错误: mediaplayer没有发布就完成了。有办法解决这个问题吗？

此外，我想淡出和淡出轨道上的过渡，从结束到开始的轨道。有没有办法听某一点的曲目，比如说在曲目结束前5秒钟，这样我就可以在尾声中淡出音轨了。

提前感谢！

异步类和logcat的代码如下：

import java.io.File;
import java.io.IOException;
import java.util.Timer;
import java.util.TimerTask;

import android.os.AsyncTask;

import android.media.MediaPlayer;
//import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.util.Log;


public class MediaPlayerController extends AsyncTask<String, String, String> {

//*******************

private final static int VOLUME_MIN = 0;

private static double VOLUME_MAX = 100;

private final static float FLOAT_VOLUME_MAX = 1.0f;
private final static float FLOAT_VOLUME_MIN = 0.0f;

private static double iVol;

private static double volChange;

private static String path;

private static MediaPlayer mMediaPlayer;

//*******************

public MediaPlayerController(int vol, String p) {
    super();
    iVol=vol;
    path=p;

    mMediaPlayer=null;

    VOLUME_MAX= iVol;

    volChange=iVol/5;

    Log.d("media player controller Async instance", "iVol "+ iVol + " vol change " + volChange);
}

 @Override
    protected void onPreExecute() {
        super.onPreExecute();
        startSound(path);

    }

    @Override
    protected String doInBackground(String... params) {

       return null;
    }

    @Override
    protected void onProgressUpdate(String... progress) {

    }
    @Override
    protected void onCancelled (){

      stopSound();
    }

    protected void onPostExecute(String file_url) {


    }

//-----------------------------------------------------------




public void startSound(String path){

    mMediaPlayer = new MediaPlayer();

    try {
        File soundFile = new File(path);
        if(soundFile.exists()){

            Log.d("start sound sound file", "exist");

            mMediaPlayer.setDataSource(path);
            mMediaPlayer.prepareAsync();

            //int dur= mMediaPlayer.getDuration();

            //Log.d("start sound mp duration", Integer.toString(dur));

            mMediaPlayer.setOnPreparedListener(new OnPreparedListener() {
                public void onPrepared(MediaPlayer mp) {

                    if (!mMediaPlayer.isPlaying())
                    startFadeInVol(1);  
                }
            }); 

        }else Log.d("start sound sound file", "NOT exist");
    }catch (IllegalArgumentException e1) {
        e1.printStackTrace();
    } catch (IllegalStateException e1) {
        e1.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}


public void stopSound() {
    if ((mMediaPlayer != null) && (mMediaPlayer.isPlaying())){

            if (mMediaPlayer.isPlaying()){
            stopFadeOutVol(1);
            Log.d("stop sound", "stopping");}   
    }       
}


private void updateVolume(double change)
{
    if((mMediaPlayer!=null) && (mMediaPlayer.isPlaying())){
    try{

    iVol =  iVol + change;

    Log.d("update vol", "iVol = "+iVol + " change " + change);

    if (iVol < VOLUME_MIN)
        iVol = VOLUME_MIN;
    else if (iVol > VOLUME_MAX)
        iVol = VOLUME_MAX;


    float fVol = 1 - ((float) Math.log(VOLUME_MAX - iVol) / (float) Math.log(VOLUME_MAX));


    if (fVol < VOLUME_MIN)
        fVol = FLOAT_VOLUME_MIN;
    else if (fVol > FLOAT_VOLUME_MAX)
        fVol = FLOAT_VOLUME_MAX;   

    Log.d("update vol fVol", Float.toString(fVol));

    mMediaPlayer.setVolume(fVol, fVol);

    }catch (Exception e){

        e.printStackTrace();
    }
}
}



public void startFadeInVol(int fadeDuration)
{
    try{

        mMediaPlayer.start();
        mMediaPlayer.setLooping(true);
        Log.d("start fade in vol", "starting");


        iVol = VOLUME_MIN;


    updateVolume(0);


    if(fadeDuration > 0)
    {
        final Timer timer = new Timer(true);
        TimerTask timerTask = new TimerTask() 
        {
            @Override
            public void run() 
            {
                updateVolume(volChange);
                if (iVol >= VOLUME_MAX)
                {
                    timer.cancel();
                    timer.purge();
                }
            }
        };

        int delay = fadeDuration*1000;
        if (delay == 0) delay = 1000;

        timer.schedule(timerTask, 0, delay);
    }
    } catch (Exception e) {
          e.printStackTrace();
      }
}

  private void stopFadeOutVol(int fadeDuration)
  {
      try {
              iVol = VOLUME_MAX;

          updateVolume(0);

          if (fadeDuration > 0)
          {
              final Timer timer = new Timer(true);
              TimerTask timerTask = new TimerTask()
              {
                  @Override
                  public void run()
                  {
                      updateVolume(-volChange);

                      if ((mMediaPlayer!=null) && (iVol <= VOLUME_MIN))
                      {

                          timer.cancel();
                          timer.purge();

                          mMediaPlayer.stop();
                          mMediaPlayer.reset();
                          mMediaPlayer.release();
                          //mMediaPlayer=null;

                          Log.d("stop fade out vol","mp stop");
                      }
                  }
              };

              int delay = fadeDuration*1000;
              if (delay == 0)
                  delay = 1000;

              timer.schedule(timerTask, 0, delay);
          }
      } catch (Exception e) {
          e.printStackTrace();
      }
  }

}

09-16 10:25:16.645: E/ExtMediaPlayer-JNI(10150)：QCMediaPlayer无法定位.09-16 10:25:16.645: E/ mediaplayer -JNI(10150)：QCMediaPlayer mediaplayer不存在09-16 10:25:16.665: v/MediaPlayer原住民:通知(8，0，0)对断开连接的mediaplayer 09-16 10:25:16.725: e/MediaPlayer原住民: MediaPlayer::getMediaSystemInfo键= 4000 09-16 10:16.735:d/MediaPlayer原住民:MediaPlayer:invoke:getparam 09-16 10:25:16.735: d/MediaPlayer原住民:MediaPlayer：：getMedia00000809-1610:25:16.735:e/MediaPlayer原住民:MediaPlayer:getMediaSystemInfo键= 4000 09-16 10:25:16.735: d/Mediaer原住民:MediaPlayer:invoke:invoke：getparam 09-16 10:25:16.735: d/MediaPlayer原住民:MediaPlayer:get参量mCurrentState = 0x00000008 09-16 10:25:16.735: e/MediaPlayer原住民: MediaPlayer::getMediaSystemInfo键= 4000 09-16 10:25:16.735: d/MediaPlayer原住民:MediaPlayer:invoke:getparam 09-16 10:25:16.735: d/MediaPlayer原住民:MediaPlayer：：getparam=0x0000008 09:16 10:16.755:v/MediaPlayer原住民:MediaPlayer:setLooping 09-16 10:25：:16.755: v/MediaPlayer原住民:MediaPlayer：：set音量(0.0000000，( 0.000000) 09-16 10:25:16.755: e/MediaPlayer原住民:MediaPlayer:getMediaSystemInfo键= 4000 09-16 10:25:16.755: d/MediaPlayer原住民:MediaPlayer:invoke:getparam 09-16 10:25:16.755: d/MediaPlayer原住民: MediaPlayer::getMediaSystemInfo =0x00001009-1610:25:16.755 v/MediaPlayer:MediaPlayer：：set音量(0.082400，0.082400) 09-1610:25:17.755:v/MediaPlayer原住民:MediaPlayer：：set卷(0.188632，0.18632)( 0.188632) 09-16 10:25:18.755: v/MediaPlayer原住民:MediaPlayer:set音量(0.338358，0.338358) 09-16 10:25:19.755: v/MediaPlayer原住民：：set音量(0.594316，0.594316) 09-16 10:25:20.755: v/MediaPlayer原住民:MediaPlayer：：set音量(1.000000，1.000000) 09-1610:26:06.955: E/ExtMediaPlayer-JNI(10150)：QCMediaPlayer无法定位.09-16 10:26:06.955: E/ mediaplayer -JNI(10150)：QCMediaPlayer mediaplayer不存在09-16 10:26:06.975: v/MediaPlayer原住民:通知(8，0，0)对断开连接的mediaplayer 09-16 10:26:07.025: e/MediaPlayer原住民: MediaPlayer::getMediaSystemInfo键= 4000 09-16 10:07.025:d/MediaPlayer原住民:MediaPlayer:invoke:getparam 09-16 10:26:07.025: d/MediaPlayer原住民:MediaPlayer：：getMedia000004-09-16 10:26:07.035: e/MediaPlayer原住民:MediaPlayer:getMediaSystemInfo键= 4000 09-16 10:26:07.035: d/Media本机:MediaPlayer:invoke:invoke：getparam 09-16 10:26:07.035: d/MediaPlayer原住民:MediaPlayer:get参量mCurrentState = 0x00000004 09-16 10:26:07.045: e/MediaPlayer原住民: MediaPlayer::getMediaSystemInfo键= 4000 09-16 10:26:07.045: 07.045:d/MediaPlayer原住民:MediaPlayer:invoke:getparam 09-16 10:26:07.045: d/MediaPlayer原住民:MediaPlayer：：get参量mCurrentState =0x00008 09-16 10:07.045:07.045:v/MediaPlayer原住民:MediaPlayer:setLooping09-16 10:26：:07.045: v/MediaPlayer原住民:MediaPlayer：：set音量(0.0000000，( 0.000000) 09-16 10:26:07.055: v/MediaPlayer原住民:MediaPlayer:set音量(0.082400，0.082400) 09-16 10:26:07.055: e/MediaPlayer原住民: MediaPlayer::getMediaSystemInfo key = 4000 09-16 10:07.055:d/MediaPlayer原住民:MediaPlayer:invoke:getparam 09-16 10:26:07.055/MediaPlayer原住民: MediaPlayer::getParameter :getPara00001009-16 10:26:08.055: v/MediaPlayer原住民:MediaPlayer：：set音量(0.188632，0.188632)0.188632) 09-16 10:26:08.295: W/ MediaPlayer -JNI(10150)：MediaPlayer最终完成而未发布09-16 10:26:09.055: v/MediaPlayer原住民:MediaPlayer：：set音量(0.338358，0.338358) 09-16 10:26:10.055: v/MediaPlayer原住民:MediaPlayer:set音量(0.594316，0.594316) 09-16 10:26:11.055: v/MediaPlayer原住民:MediaPlayer：：set音量(1.000000，1.000000)

Answer 1

问题解决了。由于其他开发人员编写的代码很差。谢谢在座的各位。