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<Map<String, Object>> mList= new ArrayList<Map<String,Object>>();
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<String,Object> mMap = null;
mList.clear();
if(files.length > 0){
for(File f:files){
mMap = new HashMap<String,Object>();
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<String, Object> 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。
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