android视频播放器关键代码

package cn.itcast.videoplayer;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();}}    }@Overrideprotected 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);}}}