android 音乐播放器简单实现

package com.zhangbz.musicplayer;

import java.io.File;

import android.app.Activity;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText et_path;
    private MediaPlayer mediaPlayer;
    private Button bt_play, bt_pause, bt_stop, bt_replay;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_path = (EditText) findViewById(R.id.et_path);
        bt_play = (Button) findViewById(R.id.bt_play);
        bt_pause = (Button) findViewById(R.id.bt_pause);
        bt_replay = (Button) findViewById(R.id.bt_replay);
        bt_stop = (Button) findViewById(R.id.bt_stop);
    }
    /**
     * 播放
     * @param view
     */
    public void play(View view) {
        String filepath = et_path.getText().toString().trim();
        File file = new File(filepath);
        if(file.exists()) {

            try {
                mediaPlayer = new MediaPlayer();
                mediaPlayer.setDataSource(filepath);//设置播放的数据源
                mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                mediaPlayer.prepare();//准备开始播放,播放的逻辑是c代码在新的线程执行。
                mediaPlayer.start();
                bt_play.setEnabled(false);
                mediaPlayer.setOnCompletionListener(new OnCompletionListener() {
                    
                    public void onCompletion(MediaPlayer arg0) {
                        bt_play.setEnabled(true);
                    }
                });
            } catch (Exception e) {
                Toast.makeText(this, "播放失败", 0).show();
                e.printStackTrace();
            }
        } else {
            Toast.makeText(this, "文件不存在，请检查文件路径", 0).show();
        }
    }
    /**
     * 暂停
     * @param view
     */
    public void pause(View view) {
        if("继续".equals(bt_pause.getText().toString().trim())) {
            mediaPlayer.start();
            bt_pause.setText("暂停");
            return;
        }
        if(mediaPlayer != null && mediaPlayer.isPlaying()) {
            mediaPlayer.pause();
            bt_pause.setText("继续");
        }
    }
    /**
     * 停止
     * @param view
     */
    public void stop(View view) {
        if(mediaPlayer != null && mediaPlayer.isPlaying()) {
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer = null;
        }
        bt_pause.setText("暂停");
        bt_play.setEnabled(true);
    }
    /**
     * 重播
     * @param view
     */
    public void replay(View view) {
        if(mediaPlayer != null && mediaPlayer.isPlaying()) {
            mediaPlayer.seekTo(0);
        } else {
            play(view);
        }
        bt_replay.setText("暂停");
    }
}