android开发之MediaPlayer+Service MP3播放器

http://blog.csdn.net/zzy916853616/article/details/6450753

 

[java]  view plain copy

 

import java.io.File;
import java.io.FilenameFilter;
import java.util.ArrayList;
import java.util.List;

import android.app.ListActivity;
import android.apps.service.PlayerService;
import android.content.Intent;
import android.media.AudioManager;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.Toast;

public class TestMediaPlayer extends ListActivity {
    /* 前段时间刚学习Android时就觉得MediaPlayer是个很神奇的东西，就试着做了个简单的音乐播放器。
     * 支持后台播放、进度条拖放、音量控制、读取sdCard音乐文件进行播放等。
     * */
    private Button playButton = null;
    private Button mFrontButton = null;
    private Button mLastButton = null;
    private Button exit = null;
    /* 声明音量管理器 */
    private AudioManager mAudioManager = null;

    /* 定义进度条 */
    public static SeekBar audioSeekBar = null;

    /* 定义音量大小 */
    private SeekBar audioVolume = null;

    /* 定于一个数据播放列表，用来存放从指定文件中搜索到的文件 */
    public static List<String> mMusicList = new ArrayList<String>();

    /* 定义音乐存放路径 */
//  private static final String MUSIC_PATH = new String("/mnt/sdcard/"); //android 2.2
    private static final String MUSIC_PATH = new String("/sdcard/");//android 2.1
    /* 定义在播放列表中的当前选择项 */
    public static int currentListItme = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        /* 更新列表 */
        musicList();
        /* 得到控件 */
        playButton = (Button) findViewById(R.id.StartMusic);
        mFrontButton = (Button) findViewById(R.id.FrontButton);
        mLastButton = (Button) findViewById(R.id.LastMusic);
        audioVolume = (SeekBar) findViewById(R.id.audioVolume);
        exit = (Button)findViewById(R.id.exit);
        audioSeekBar = (SeekBar) findViewById(R.id.seekbar01);
        /* 播放、暂停监听 */
        playButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {

                playMusic(AppConstant.PlayerMag.PAUSE);
            }
        });
        /* 监听下一首 */
        mFrontButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                nextMusic();
            }
        });
        /* 监听上一首 */
        mLastButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                FrontMusic();
            }
        });
        /*退出监听*/
        exit.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent();
                intent.setClass(TestMediaPlayer.this, PlayerService.class);
                stopService(intent);//停止Service
                try {
                    TestMediaPlayer.this.finish();//关闭当前Activity
                } catch (Throwable e) {
                    e.printStackTrace();
                }


            }
        });
        /* 播放进度监听 */
        audioSeekBar.setOnSeekBarChangeListener(new SeekBarChangeEvent());
        /*退出后再次进去程序时，进度条保持持续更新*/
        if(PlayerService.mMediaPlayer!=null){
            //设置进度条最大值
            TestMediaPlayer.audioSeekBar.setMax(PlayerService.mMediaPlayer.getDuration());
            audioSeekBar.setProgress(PlayerService.mMediaPlayer.getCurrentPosition());
        }


        /* 得到当前音量对象 */
        mAudioManager = (AudioManager) getSystemService(AUDIO_SERVICE);
        /* 把当前音量值赋给进度条 */
        audioVolume.setProgress(mAudioManager
                .getStreamVolume(AudioManager.STREAM_MUSIC));
        /* 监听音量 */
        audioVolume.setOnSeekBarChangeListener(new AudioVolumeChangeEvent());
    }

    public void playMusic(int action) {
        Intent intent = new Intent();
        intent.putExtra("MSG", action);
        intent.setClass(TestMediaPlayer.this, PlayerService.class);

        /* 启动service service要在AndroidManifest.xml注册如：<service></service>*/

        startService(intent);
    }

    /* 检测sdcard MP3文件并加入到List列表 */
    public void musicList() {
        // 先清除list中的缓存
        mMusicList.clear();
        /* 从指定的路径中读取文件，并与播放列表关联 */
        File home = new File(MUSIC_PATH);

        System.out.println(home.canRead());
        /* 读取指定类型的文件，在本程序，指定播放类型为mp3 */
        if (home.listFiles(new MusicFilter()).length > 0) {
            /* 读取文件 */
            for (File file : home.listFiles(new MusicFilter())) {
                mMusicList.add(file.getName());
            }
            /* 播放文件与播放列表关联 */
            ArrayAdapter<String> musicList = new ArrayAdapter<String>(
                    TestMediaPlayer.this, R.layout.musictime, mMusicList);
            setListAdapter(musicList);
        }
    }

    /* 音量监听 */
    class AudioVolumeChangeEvent implements SeekBar.OnSeekBarChangeListener {

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress,
                boolean fromUser) {

            // mAudioManager.adjustVolume(AudioManager.ADJUST_LOWER, 0);
            mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, progress,
                    0);

        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
        }

    }

    /* 音乐选择监听 */
    @Override
    protected void onListItemClick(android.widget.ListView l, View v,
            int position, long id) {
        super.onListItemClick(l, v, position, id);
        currentListItme = position;
        playMusic(AppConstant.PlayerMag.PLAY_MAG);
    }

    /* 播放下一首 */
    private void nextMusic() {
        if (++currentListItme >= mMusicList.size()) {
            Toast.makeText(TestMediaPlayer.this, "已到最后一首歌曲", Toast.LENGTH_SHORT)
                    .show();
            currentListItme = mMusicList.size() - 1;
        } else {
            playMusic(AppConstant.PlayerMag.PLAY_MAG);
        }
    }

    /* 播放上一首歌曲 */
    private void FrontMusic() {
        if (--currentListItme >= 0) {
            playMusic(AppConstant.PlayerMag.PLAY_MAG);

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

/* 播放文件选择类 */
class MusicFilter implements FilenameFilter {
    public boolean accept(File dir, String name) {
        /* 指定扩展名类型 ，可以加其他的音乐格式*/
        return (name.endsWith(".mp3"));
    }
}

/* 拖放进度监听 ，别忘了Service里面还有个进度条刷新*/
class SeekBarChangeEvent implements SeekBar.OnSeekBarChangeListener {

    @Override
    public void onProgressChanged(SeekBar seekBar, int progress,
            boolean fromUser) {
        /*假设改变源于用户拖动*/
        if (fromUser) {
            PlayerService.mMediaPlayer.seekTo(progress);// 当进度条的值改变时，音乐播放器从新的位置开始播放
        }
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        PlayerService.mMediaPlayer.pause(); // 开始拖动进度条时，音乐暂停播放
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        PlayerService.mMediaPlayer.start(); // 停止拖动进度条时，音乐开始播放
    }
}

service类

首先建议不要把播放音乐放在Activity中，因为关闭Activity后就不能实现后台播放。所以播放音乐要放在Service中，我们只需要管理Activity与Service间的通信就好了。下面就是个Service类。直接看注释和代码：

package android.apps.service;

import java.io.IOException;

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

import android.apps.*;

public class PlayerService extends Service implements Runnable,
        MediaPlayer.OnCompletionListener {
    /* 定于一个多媒体对象 */
    public static MediaPlayer mMediaPlayer = null;
    // 是否单曲循环
    private static boolean isLoop = false;
    // 用户操作
    private int MSG;

    /* 定义要播放的文件夹路径 */
    private static final String MUSIC_PATH = new String("/sdcard/");

    @Override
    public IBinder onBind(Intent intent) {
        return null;// 这里的绑定没的用，上篇我贴出了如何将activity与service绑定的代码
    }

    @Override
    public void onCreate() {
        super.onCreate();
        if (mMediaPlayer != null) {
            mMediaPlayer.reset();
            mMediaPlayer.release();
            mMediaPlayer = null;
        }
        mMediaPlayer = new MediaPlayer();
        /* 监听播放是否完成 */
        mMediaPlayer.setOnCompletionListener(this);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        if (mMediaPlayer != null) {
            mMediaPlayer.stop();
            mMediaPlayer.release();
            mMediaPlayer = null;
        }

        System.out.println("service onDestroy");
    }
    /*启动service时执行的方法*/
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        /*得到从startService传来的动作，后是默认参数，这里是我自定义的常量*/
        MSG = intent.getIntExtra("MSG", AppConstant.PlayerMag.PLAY_MAG);
        if (MSG == AppConstant.PlayerMag.PLAY_MAG) {
            playMusic();
        }
        if (MSG == AppConstant.PlayerMag.PAUSE) {
            if (mMediaPlayer.isPlaying()) {// 正在播放
                mMediaPlayer.pause();// 暂停
            } else {// 没有播放
                mMediaPlayer.start();
            }
        }

        return super.onStartCommand(intent, flags, startId);
    }

    @SuppressWarnings("static-access")
    public void playMusic() {
        try {
            /* 重置多媒体 */
            mMediaPlayer.reset();
            /* 读取mp3文件 */
            mMediaPlayer.setDataSource(MUSIC_PATH+TestMediaPlayer.mMusicList.get(TestMediaPlayer.currentListItme));
//          Uri uri = Uri.parse(MUSIC_PATH+TestMediaPlayer.mMusicList.get(TestMediaPlayer.currentListItme));
//
//          mMediaPlayer.create(PlayerService.this,uri);
            /* 准备播放 */
            mMediaPlayer.prepare();
            /* 开始播放 */
            mMediaPlayer.start();
            /* 是否单曲循环 */
            mMediaPlayer.setLooping(isLoop);
            // 设置进度条最大值
            TestMediaPlayer.audioSeekBar.setMax(PlayerService.mMediaPlayer
                    .getDuration());
            new Thread(this).start();
        } catch (IOException e) {
        }

    }

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

    }

    @Override
    public void onCompletion(MediaPlayer mp) {
        /* 播放完当前歌曲，自动播放下一首 */

        if (++TestMediaPlayer.currentListItme >= TestMediaPlayer.mMusicList
                .size()) {
            Toast.makeText(PlayerService.this, "已到最后一首歌曲", Toast.LENGTH_SHORT)
                    .show();
            TestMediaPlayer.currentListItme--;
            TestMediaPlayer.audioSeekBar.setMax(0);
        } else {
            playMusic();
        }
    }
}

参数封装

/**
 * @把参数这样封装易于管理和阅读
 *
 */
public interface AppConstant {
    public class PlayerMag{
        public static final int PLAY_MAG=1;//开始播放
        public static final int PAUSE=2;//暂停播放
    }
}

详细代码下载：http://download.csdn.net/source/3318587