Android视频播放器关键代码

import java.io.File;    import android.app.Activity;  import android.media.MediaPlayer;  import android.media.MediaPlayer.OnPreparedListener;  import android.os.Bundle;  import android.os.Environment;  import android.view.SurfaceHolder;  import android.view.SurfaceHolder.Callback;  import android.view.SurfaceView;  import android.view.View;  import android.widget.EditText;  import android.widget.Toast;    public class MainActivity extends Activity {      private EditText nameText;      private String path;      private MediaPlayer mediaPlayer;      private SurfaceView surfaceView;      private boolean pause;      private int position;            @Override      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.main);                    mediaPlayer = new MediaPlayer();          nameText = (EditText) this.findViewById(R.id.filename);          surfaceView = (SurfaceView) this.findViewById(R.id.surfaceView);          //把输送给surfaceView的视频画面，直接显示到屏幕上,不要维持它自身的缓冲区          surfaceView.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);          surfaceView.getHolder().setFixedSize(176, 144);          surfaceView.getHolder().setKeepScreenOn(true);          surfaceView.getHolder().addCallback(new SurfaceCallback());      }            private final class SurfaceCallback implements Callback{    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {    }    public void surfaceCreated(SurfaceHolder holder) {     if(position>0 && path!=null){      play(position);      position = 0;     }    }    public void surfaceDestroyed(SurfaceHolder holder) {     if(mediaPlayer.isPlaying()){      position = mediaPlayer.getCurrentPosition();      mediaPlayer.stop();     }    }      }     @Override   protected void onDestroy() {       mediaPlayer.release();       mediaPlayer = null;    super.onDestroy();   }     public void mediaplay(View v){       switch (v.getId()) {    case R.id.playbutton:     String filename = nameText.getText().toString();     if(filename.startsWith("http")){      path = filename;      play(0);     }else{      File file = new File(Environment.getExternalStorageDirectory(), filename);      if(file.exists()){       path = file.getAbsolutePath();       play(0);      }else{       path = null;       Toast.makeText(this, R.string.filenoexsit, 1).show();      }     }         break;      case R.id.pausebutton:     if(mediaPlayer.isPlaying()){      mediaPlayer.pause();      pause = true;     }else{      if(pause){       mediaPlayer.start();       pause = false;      }     }     break;         case R.id.resetbutton:     if(mediaPlayer.isPlaying()){      mediaPlayer.seekTo(0);     }else{      if(path!=null){       play(0);      }     }     break;    case R.id.stopbutton:     if(mediaPlayer.isPlaying()){      mediaPlayer.stop();     }     break;    }      }     private void play(int position) {    try {     mediaPlayer.reset();     mediaPlayer.setDataSource(path);     mediaPlayer.setDisplay(surfaceView.getHolder());     mediaPlayer.prepare();//缓冲     mediaPlayer.setOnPreparedListener(new PrepareListener(position));    } catch (Exception e) {     e.printStackTrace();    }   }      private final class PrepareListener implements OnPreparedListener{    private int position;        public PrepareListener(int position) {         this.position = position;    }      public void onPrepared(MediaPlayer mp) {     mediaPlayer.start();//播放视频     if(position>0) mediaPlayer.seekTo(position);    }   }  }