Android之音乐播发(二)

package cn.itcast.audio;import java.io.File;import java.io.IOException;import android.app.Activity;import android.media.MediaPlayer;import android.os.Bundle;import android.os.Environment;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.EditText;public class PlayActivity extends Activity {	private static final String TAG = "PlayActivity";    private EditText filenameText;    private MediaPlayer mediaPlayer;    private String filename;    private int position;        @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        filenameText = (EditText)this.findViewById(R.id.filename);               mediaPlayer = new MediaPlayer();        ButtonClickListener listener = new ButtonClickListener();        Button playButton = (Button)this.findViewById(R.id.play);        Button pauseButton = (Button)this.findViewById(R.id.pause);        Button resetButton = (Button)this.findViewById(R.id.reset);        Button stopButton = (Button) this.findViewById(R.id.stop);        playButton.setOnClickListener(listener);        pauseButton.setOnClickListener(listener);        resetButton.setOnClickListener(listener);        stopButton.setOnClickListener(listener);        Log.i(TAG, "onCreate()");    }        @Override	protected void onRestoreInstanceState(Bundle savedInstanceState) {		this.filename = savedInstanceState.getString("filename");		this.position = savedInstanceState.getInt("position");		super.onRestoreInstanceState(savedInstanceState);		Log.i(TAG, "onRestoreInstanceState()");	}	@Override	protected void onSaveInstanceState(Bundle outState) {		outState.putString("filename", filename);		outState.putInt("position", position);		super.onSaveInstanceState(outState);		Log.i(TAG, "onSaveInstanceState()");	}	@Override	protected void onPause() {//如果突然电话到来，停止播放音乐		if(mediaPlayer.isPlaying()){			position = mediaPlayer.getCurrentPosition();//保存当前播放点			mediaPlayer.stop();		}		super.onPause();	}	@Override	protected void onResume() {		if(position>0 && filename!=null){//如果电话结束，继续播放音乐			try {				play();				mediaPlayer.seekTo(position);				position = 0;			} catch (IOException e) {				Log.e(TAG, e.toString());			}		}		super.onResume();	}	@Override	protected void onDestroy() {    	mediaPlayer.release();     		super.onDestroy();		Log.i(TAG, "onDestroy()");	}	private final class ButtonClickListener implements View.OnClickListener{		@Override		public void onClick(View v) {			filename = filenameText.getText().toString();//先得到文本框中的内容			Button button = (Button) v;//得到button 			try {				switch (v.getId()) {//通过传过来的Buttonid可以判断Button的类型				case R.id.play://播放					play();					break;				case R.id.pause:					if(mediaPlayer.isPlaying()){						mediaPlayer.pause();						button.setText(R.string.continue1);//让这个按钮上的文字显示为继续					}else{						mediaPlayer.start();//继续播放						button.setText(R.string.pause);					}					break;									case R.id.reset:					if(mediaPlayer.isPlaying()){						mediaPlayer.seekTo(0);//让它从0开始播放					}else{						play();//如果它没有播放，就让它开始播放					}					break;									case R.id.stop:					if(mediaPlayer.isPlaying()) mediaPlayer.stop();//如果它正在播放的话，就让他停止					break;				}			} catch (Exception e) {//抛出异常				Log.e(TAG, e.toString());			}		}		    }	private void play() throws IOException {		File audioFile = new File(Environment.getExternalStorageDirectory(),filename);		mediaPlayer.reset();		mediaPlayer.setDataSource(audioFile.getAbsolutePath());		mediaPlayer.prepare();		mediaPlayer.start();//播放	}}

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