android开发之MediaPlayer+Service MP3播放器

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

[java] view plaincopy

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：

[java] view plaincopy

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

[java] view plaincopy

/**

* @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