[Android]结合MediaPlayer和Service的音乐播放器

通过参照网上其他人的MP3播放器，自己也在这些基础上小试牛刀，制作的了一个MP3的播放器，先上个界面先：

接下来就上代码：

首先是.mp3格式的音乐文件的过滤类单独在一个java文件中：

package com.example.mediaplayer;

import java.io.File;
import java.io.FilenameFilter;

public class MusicFilter implements FilenameFilter{

    @Override
    public boolean accept(File dir, String filename) {
        // TODO Auto-generated method stub
        return (filename.endsWith(".mp3"));
    }

}

下面是MainActivity.java中的代码(其中音量和播放进度的方法是参照网上别人的)：

package com.example.mediaplayer;

import java.io.File;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import android.media.AudioManager;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.ListActivity;
import android.content.Intent;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.ListView;
import android.widget.SeekBar;
import android.widget.SimpleAdapter;
import android.widget.Toast;

public class MainActivity extends ListActivity {
    public static ImageButton start_btn;
    private ImageButton last_btn;
    private ImageButton next_btn;
    public static SeekBar progressBar;
    private SeekBar volumeBar;

    public static List> mList= new ArrayList>();
    public static int currentListItem=0;//当前播放歌曲的索引
    @SuppressLint("SdCardPath")
    public static String MUSIC_PATH = new String("/mnt/sdcard/Music/");
    public static AudioManager audioManager=null;
    private String[] mFrom=new String[]{"img","music_name"};
    private int[] mTo=new int[]{R.id.img, R.id.music_name};

    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        musicList();
        init();
    }
    /*初始化Button*/
    private void init(){
        next_btn= (ImageButton) this.findViewById(R.id.next_btn);
        next_btn.setOnClickListener(btnListen);
        start_btn = (ImageButton) this.findViewById(R.id.start_btn);
        start_btn.setOnClickListener(btnListen);
        last_btn= (ImageButton) this.findViewById(R.id.last_btn);
        last_btn.setOnClickListener(btnListen);
        volumeBar=(SeekBar) this.findViewById(R.id.volume_seekBar);
        progressBar =(SeekBar) this.findViewById(R.id.progressBar);

        /*进度条监听*/
        progressBar.setOnSeekBarChangeListener(new ProgressBarChange());
        /*退出后再次进去程序时，进度条保持持续更新*/
        if(PlayerService.mediaPlayer!=null){
            //设置进度条最大值
            MainActivity.progressBar.setMax(PlayerService.mediaPlayer.getDuration());
            progressBar.setProgress(PlayerService.mediaPlayer.getCurrentPosition());
        }



        audioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
        /* 把当前音量值赋给进度条 */
        volumeBar.setProgress(audioManager  .getStreamVolume(AudioManager.STREAM_MUSIC));
        /* 监听音量 */
        volumeBar.setOnSeekBarChangeListener(new VolumeBarChang());
    }
    /*设置按键监听*/
    private OnClickListener btnListen = new OnClickListener() {
        @Override
        public void onClick(View v) {
            switch (v.getId()) {
            case R.id.start_btn:
                {
                    if(PlayerService.mediaPlayer.isPlaying()){
                        playMusic(AppConstant.PlayerMag.PAUSE);
                        start_btn.setImageDrawable(getResources().getDrawable(R.drawable.pause_round));
                    }else{
                        playMusic(AppConstant.PlayerMag.PLAY);
                        start_btn.setImageDrawable(getResources().getDrawable(R.drawable.play_round));
                    }
                }
                break;
            case R.id.next_btn:
                nextMusic();
                break;
            case R.id.last_btn:
                frontMusic();
                break;
            default:
                break;
            }
        }
    };
    /*显示歌曲到listView*/
    public void musicList(){
        File home= new File(MUSIC_PATH);
        File[] files=home.listFiles(new MusicFilter());
        Map mMap = null;
        mList.clear();
        if(files.length > 0){
            for(File f:files){
                mMap = new HashMap();
                mMap.put("img", R.drawable.music_round);
                mMap.put("music_name", f.getName());
                mList.add(mMap);
            }
        }
        SimpleAdapter mAdapter = new SimpleAdapter(this, mList, R.layout.item, mFrom, mTo);
        setListAdapter(mAdapter);
    }

    //播放音乐
   public void playMusic(int action){
       Intent intent = new Intent();
       intent.putExtra("CMD", action);
       intent.putExtra("ITEM", currentListItem);
       intent.setClass(MainActivity.this, PlayerService.class);
       startService(intent);
   }

   //下一首
   public void nextMusic(){
       if (++currentListItem >= mList.size()) {
           Toast.makeText(MainActivity.this, "已到最后一首歌曲", Toast.LENGTH_SHORT)  .show();
           currentListItem = mList.size() - 1;
       } else {
            playMusic(AppConstant.PlayerMag.PLAY);
       }

   }

   //上一首
    public void frontMusic(){
       if (--currentListItem > 0) {
            playMusic(AppConstant.PlayerMag.PLAY);

       } else {
           Toast.makeText(MainActivity.this, "已到第一首歌曲", Toast.LENGTH_SHORT)
                   .show();
           currentListItem = 0;
       }
   }

    /* 音乐选择监听
    * 用户点击listview的栏目，直接播放
    * */
   @Override
    protected void onListItemClick(ListView l, View v, int position, long id) {
        currentListItem = position;
        playMusic(AppConstant.PlayerMag.PLAY);

    }
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub
        if(keyCode == KeyEvent.KEYCODE_BACK){
            this.finish();
        }
        return super.onKeyDown(keyCode, event);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // TODO Auto-generated method stub
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // TODO Auto-generated method stub
        if(item.getItemId() == R.id.exit){
            Intent intent = new Intent();
            intent.setClass(MainActivity.this, PlayerService.class);
            stopService(intent);//停止Service
            MainActivity.this.finish();
        }
        return super.onOptionsItemSelected(item);
    }
}

其中进度和音量的实现如下：

package com.example.mediaplayer;

import android.widget.SeekBar;


/*
 * 播放进度监听
 * */
public class ProgressBarChange implements SeekBar.OnSeekBarChangeListener{

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
            boolean fromUser) {
        // TODO Auto-generated method stub
        // 当进度条的值改变时，音乐播放器从新的位置开始播放
        if(fromUser){
            PlayerService.mediaPlayer.seekTo(progress);
        }

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub
        PlayerService.mediaPlayer.pause(); // 开始拖动进度条时，音乐暂停播放

    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub
        PlayerService.mediaPlayer.start();// 停止拖动进度条时，音乐开始播放
    }

}

package com.example.mediaplayer;

import android.media.AudioManager;
import android.widget.SeekBar;


/*
 * 音量监听
 * */
public class VolumeBarChang implements SeekBar.OnSeekBarChangeListener{

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
            boolean fromUser) {
        // TODO Auto-generated method stub
        MainActivity.audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, progress,
                 0);

    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        // TODO Auto-generated method stub

    }

}

最后就是service部分的了：

package com.example.mediaplayer;
import java.io.IOException;
import java.util.Map;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.os.IBinder;
import android.widget.Toast;


public class PlayerService extends Service implements Runnable,
            MediaPlayer.OnCompletionListener{

    public static MediaPlayer mediaPlayer=null;
    private static boolean isLoop=false;
    private String path = null;
    private int CMD;


    @Override
    public void onCreate() {
        // TODO Auto-generated method stub
        super.onCreate();
        if(mediaPlayer != null){
            mediaPlayer.reset();
            mediaPlayer.release();
            mediaPlayer=null;
        }
        mediaPlayer=new MediaPlayer();
        mediaPlayer.setOnCompletionListener(this);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        // TODO Auto-generated method stub
        CMD=(int)intent.getIntExtra("CMD", AppConstant.PlayerMag.PLAY);

        if(CMD == AppConstant.PlayerMag.PLAY){
            playMusic((int)intent.getIntExtra("ITEM",MainActivity.currentListItem));
        }else if(CMD == AppConstant.PlayerMag.PAUSE){
            if(mediaPlayer.isPlaying()){
                mediaPlayer.pause();
            }else {
                mediaPlayer.start();
            }

        }
        new Thread(this).start();//进度条开始
        return super.onStartCommand(intent, flags, startId);
    }

    public void playMusic(int item) {
        try {
            Map map = MainActivity.mList.get(item);
            path=MainActivity.MUSIC_PATH+map.get("music_name");

            mediaPlayer.reset();
            mediaPlayer.setDataSource(path);
            mediaPlayer.prepare();
            mediaPlayer.start();
            mediaPlayer.setLooping(isLoop);

            MainActivity.progressBar.setMax(PlayerService.mediaPlayer.getDuration());//设置播放进度条的最大值
        } catch (IllegalArgumentException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SecurityException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IllegalStateException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    @Override
    public IBinder onBind(Intent intent) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        if(mediaPlayer != null){
            mediaPlayer.stop();
            mediaPlayer.release();
            mediaPlayer=null;
        }
    }

    @Override
    public void run() {
        int currentPosition = 0;// 设置默认进度条当前位置
        int total = mediaPlayer.getDuration();//
        while (mediaPlayer != null && currentPosition < total) {
            try {
                Thread.sleep(1000);
                if (mediaPlayer != null) {
                    currentPosition = mediaPlayer.getCurrentPosition();
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            MainActivity.progressBar.setProgress(currentPosition);
        }

    }
    @Override
    public void onCompletion(MediaPlayer mp) {
        /*当前歌曲播放完，自动播放跳到下一首*/
        if (++MainActivity.currentListItem >= MainActivity.mList.size()) {
            Toast.makeText(PlayerService.this, "已到最后一首歌曲", Toast.LENGTH_SHORT)
                    .show();
            MainActivity.currentListItem--;
            MainActivity.progressBar.setMax(0);
        } else {

            playMusic(MainActivity.currentListItem);

        }
        MainActivity.start_btn.setImageDrawable(getResources().getDrawable(R.drawable.play_round));
    }
}

业余时间第一次去做算是比较完整小应用，其中学到真的还是很多的，其中很多是在blog的各大神中学的，

所以自己也要把这次发布出来，希望各位大神级的多多指点下我这种菜鸟。