将进度条与音频歌曲同步

Question

我正在播放来自SD卡的歌曲。

它播放得很好。我尝试实现一个进度条，以便当用户移动进度条时，根据进度条的位置向前或向后调整歌曲。

以下是代码：

public class ViewAudio extends Activity implements  OnSeekBarChangeListener,OnSeekCompleteListener,OnCompletionListener,OnPreparedListener{
 @Override
  public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.audio_player);

        System.gc();
        Intent i = getIntent();
        Bundle extras = i.getExtras();
        filename = extras.getString("audiofilename");

        try {
            mPlayer.setDataSource(filename);
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        try {
            mPlayer.prepare();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


        mPlayer.setOnCompletionListener(this);
        mPlayer.setOnPreparedListener(this);
        mPlayer.setOnSeekCompleteListener((OnSeekCompleteListener) this);

        mPlayer.start();

        TextView tv=(TextView) findViewById(R.id.file);
        tv.setText("Playing "+filename);

        seekbar = (SeekBar)findViewById(R.id.seekBar1);
        mPlay = (Button)findViewById(R.id.play);
        mPause = (Button)findViewById(R.id.pause);

        seekbar.setProgress(0);
        seekbar.setOnSeekBarChangeListener(this);
        total = mPlayer.getDuration();

  }
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
        boolean fromUser) {
    Log.d("Progres changed",""+progress);

    if(fromUser){
        mPlayer.seekTo(progress);
        seekbar.setProgress(progress);

    }

}

}

现在，无论我在进度条上点击哪里，歌曲都会从开头播放，而不是从我点击的位置开始播放。并且它不会根据歌曲移动。

请有人帮忙解决。

- John

Answer 1

我已经解决了。 创建一个线程，每秒钟检查一次歌曲位置，并根据歌曲位置移动滑块。

  mediaPos = mplayer.getCurrentPosition();
  mediaMax = mplayer.getDuration();

  seekbar.setMax(mediaMax); // Set the Maximum range of the
  seekbar.setProgress(mediaPos);// set current progress to song's

  handler.removeCallbacks(moveSeekBarThread);
  handler.postDelayed(moveSeekBarThread, 100); //cal the thread after 100 milliseconds


}
  /**
 * The Move seek bar. Thread to move seekbar based on the current position
 * of the song
 */
private Runnable moveSeekBarThread = new Runnable() {
    public void run() {
            if(mplayer.isPlaying()){

            int mediaPos_new = mPlayer.getCurrentPosition();
            int mediaMax_new = mPlayer.getDuration();
            seekbar.setMax(mediaMax_new);
            seekbar.setProgress(mediaPos_new);

            handler.postDelayed(this, 100); //Looping the thread after 0.1 second
    }

    }
};

- John