android_简洁音乐播放器(有播放/暂停等功能)_

package com.terry;

import java.io.File;
import java.util.ArrayList;
import java.util.List; 
import android.app.ListActivity;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.Toast;

public class musicActivity extends ListActivity {
	//播放对象
	private MediaPlayer myMediaPlayer;
	//播放列表
	private List<String> myMusicList=new ArrayList<String>();
	//当前播放歌曲的索引
	private int currentListItem=0;
	//音乐的路径
	private static final String MUSIC_PATH=new String("/sdcard/");
	
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    myMediaPlayer=new MediaPlayer();
    
    findView();
    musicList();
    listener();
  }
  
  
  //绑定音乐
  void musicList(){
  	File home=new File(MUSIC_PATH);
  	if(home.listFiles(new MusicFilter()).length>0){
  		for(File file:home.listFiles(new MusicFilter())){
  			myMusicList.add(file.getName());
  		}
  		ArrayAdapter<String> musicList=new ArrayAdapter<String>
  		(musicActivity.this,R.layout.musicitme, myMusicList);
  		setListAdapter(musicList);
  	}
  }
  
  //获取按钮
  void findView(){
	  viewHolder.start=(Button)findViewById(R.id.start);
	  viewHolder.stop=(Button)findViewById(R.id.stop);
	  viewHolder.next=(Button)findViewById(R.id.next);
	  viewHolder.pause=(Button)findViewById(R.id.pause);
	  viewHolder.last=(Button)findViewById(R.id.last);
  }
  
  
  //监听事件
  void listener(){
	  //停止
	  viewHolder.stop.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			if(myMediaPlayer.isPlaying()){
				myMediaPlayer.reset();
			}
		}
	});
	  //开始
	  viewHolder.start.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			playMusic(MUSIC_PATH myMusicList.get(currentListItem));
		}
	});
	  //下一首
	  viewHolder.next.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			nextMusic();
		}
	});
	  //暂停
	  viewHolder.pause.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			if(myMediaPlayer.isPlaying()){
				myMediaPlayer.pause();
			}else{
				myMediaPlayer.start();
			}
		}
	});
	  //上一首
	  viewHolder.last.setOnClickListener(new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			
			lastMusic();
		}
	});
	  
  }
  
  //播放音乐 
  void playMusic(String path){
	  try { 
		myMediaPlayer.reset();
		myMediaPlayer.setDataSource(path);
		myMediaPlayer.prepare();
		myMediaPlayer.start();
		myMediaPlayer.setOnCompletionListener(new OnCompletionListener() {
			
			@Override
			public void onCompletion(MediaPlayer mp) {
				// TODO Auto-generated method stub
				nextMusic();
			}
		});
	} catch (Exception e) {
		// TODO: handle exception
		e.printStackTrace();
	}
  }
  
  //下一首
  void nextMusic(){
	  if( currentListItem>=myMusicList.size()){
		  currentListItem=0;
	  }
	  else{
		  playMusic(MUSIC_PATH myMusicList.get(currentListItem));
	  }
  }
  
  //上一首
  void lastMusic(){
	  if(currentListItem!=0)
		  {
	  if(--currentListItem>=0){
		  currentListItem=myMusicList.size();
	  } else{
		  playMusic(MUSIC_PATH myMusicList.get(currentListItem));
	  }
		 } else{
		  playMusic(MUSIC_PATH myMusicList.get(currentListItem));
	  }
  }
  
  //当用户返回时结束音乐并释放音乐对象
	  @Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		// TODO Auto-generated method stub
		  if(keyCode==KeyEvent.KEYCODE_BACK){
			  myMediaPlayer.stop();
			  myMediaPlayer.release();
			  this.finish();
			  return true;
		  }
		return super.onKeyDown(keyCode, event);
	}
  
	  //当选择列表项时播放音乐 
	  @Override
	protected void onListItemClick(ListView l, View v, int position, long id) {
		// TODO Auto-generated method stub
		currentListItem=position;
		playMusic(MUSIC_PATH myMusicList.get(currentListItem));
	}
  
}