android应用学习---18.MediaPlayer实现音乐播放的demo

一.使用MediaPlayer播放音乐的demo
1. 添加权限
因为音乐文件在sdcard中，所以需要添加外置sd卡的访问权限
AndroidManifest.xml

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

2. demo代码如下

package com.example.MediaPlay;

import java.io.File;
import com.example.MediaPlay.R;
import android.app.Activity;
import android.view.View;
import android.widget.Button;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Bundle;

public class MediaPlay extends Activity
{
    private String TAG = "cong";
    private Button btn_play, btn_pause, btn_stop;
    private MediaPlayer mediaPlayer;
    private String File_Path = "/mnt/sdcard/Music/letitgo.mp3";     //音乐文件的路径
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn_play = (Button) findViewById(R.id.btn_play);
        btn_pause = (Button) findViewById(R.id.btn_pause);
        btn_stop = (Button) findViewById(R.id.btn_stop);

        btn_play.setOnClickListener(click);
        btn_pause.setOnClickListener(click);
        btn_stop.setOnClickListener(click);
    }
    private View.OnClickListener click = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
            case R.id.btn_play:
                play();
                break;
            case R.id.btn_pause:
                pause();
                break;
            case R.id.btn_stop:
                stop();
                break;
            default:
                break;
            }
        }
    };

    protected void play() {
        File file = new File(File_Path);    //确认音乐文件的存在
        if(!file.exists())
            return ;
        try {
            mediaPlayer = new MediaPlayer();
            mediaPlayer.setDataSource(File_Path);
            mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mediaPlayer.prepareAsync();       //异步的方式加载音乐文件
            mediaPlayer.setOnPreparedListener(new OnPreparedListener() {  //异步加载完音乐文件后会回调此
                @Override
                public void onPrepared(MediaPlayer mp) {
                    mediaPlayer.start();               //准备好之后才能start
                    btn_play.setEnabled(false);
                }
            });
            mediaPlayer.setOnCompletionListener(new OnCompletionListener() {
                @Override
                public void onCompletion(MediaPlayer mp) {
                    btn_play.setEnabled(true);             //播放完成后btn_play可用
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    protected void pause() {
        if (mediaPlayer != null && !mediaPlayer.isPlaying()) {
            mediaPlayer.start();
            btn_pause.setText("pause");
            return;
        }
        if (mediaPlayer != null && mediaPlayer.isPlaying()) {
            mediaPlayer.pause();
            btn_pause.setText("continue");
        }
    }

    protected void stop() {
        if (mediaPlayer != null && mediaPlayer.isPlaying()) {
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer = null;
            btn_play.setEnabled(true);
        }
    }

    @Override
    protected void onDestroy() {
        if (mediaPlayer != null && mediaPlayer.isPlaying()) {
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer = null;
        }
        super.onDestroy();
    }
}

media.rar (下载后改名为media.tar.gz解压)