音乐播放器

public class MainActivity extends Activity {
    private EditText nameText;
    private String path;
    private MediaPlayer mediaPlayer;
    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);
        //处理来电情况
        TelephonyManager telephonyManager = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);
        telephonyManager.listen(new MyPhoneListener(), PhoneStateListener.LISTEN_CALL_STATE);
    }
    
    private final class MyPhoneListener extends PhoneStateListener{
        public void onCallStateChanged(int state, String incomingNumber) {
            switch (state) {
            case TelephonyManager.CALL_STATE_RINGING://来电
                if(mediaPlayer.isPlaying()) {
                    position = mediaPlayer.getCurrentPosition();
                    mediaPlayer.stop();
                }
                break;

            case TelephonyManager.CALL_STATE_IDLE:
                if(position>0 && path!=null){
                    play(position);
                    position = 0;
                }
                break;
            }
        }
    }
    /*
    @Override
    protected void onPause() {
        if(mediaPlayer.isPlaying()) {
            position = mediaPlayer.getCurrentPosition();
            mediaPlayer.stop();
        }
        super.onPause();
    }

    @Override
    protected void onResume() {
        if(position>0 && path!=null){
            play(position);
            position = 0;
        }
        super.onResume();
    }
*/
    @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();
            File audio = new File(Environment.getExternalStorageDirectory(), filename);
            if(audio.exists()){
                path = audio.getAbsolutePath();
                play(0);
            }else{
                path = null;
                Toast.makeText(getApplicationContext(), R.string.filenoexist, 1).show();
            }
            break;
            
        case R.id.pausebutton:
            if(mediaPlayer.isPlaying()){
                mediaPlayer.pause();//暂停
                pause = true;
                ((Button)v).setText(R.string.continues);
            }else{
                if(pause){
                    mediaPlayer.start();//继续播放
                    pause = false;
                    ((Button)v).setText(R.string.pausebutton);
                }
            }
            break;
        case R.id.resetbutton:
            if(mediaPlayer.isPlaying()){
                mediaPlayer.seekTo(0);//从开始位置播放音乐
            }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();//把各项参数恢复到初始状态
            mediaPlayer.setDataSource(path);
            mediaPlayer.prepare();//进行缓冲
            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();//开始播放
            if(position>0) mediaPlayer.seekTo(position);
        }
    }
}