public class MainActivity extends Activity {
	private Button btn;
	private ProgressDialog dialog;	//进度条
	private MyAsyncTasck myAsyncTasck;
    @Override
    
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn = (Button)this.findViewById(R.id.button1);
        btn.setOnClickListener(new ButtonClickListener());
    }
    
    

    //点击按钮的监听
    class ButtonClickListener implements OnClickListener{
		@Override
		public void onClick(View view) {
			myAsyncTasck = new MyAsyncTasck();
			myAsyncTasck.execute();
		}
    	
    }
    
    class MyAsyncTasck extends AsyncTask<String,Integer,Object>{
    	//准备前
    	@Override
		protected void onPreExecute() {
			super.onPreExecute();
			dialog = (ProgressDialog)new ProgressDialog(MainActivity.this);
			dialog.setTitle("下载中....");
			dialog.setMessage("mp3文件下载中");
			dialog.setMax(100);	//最大长度
			//风格样式
			dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
			//当前位置
			dialog.setProgress(0);
			dialog.setIndeterminate(false);
			//处理Bug
			dialog.show();
		}

    	//前台线程
    	@Override
		protected void onProgressUpdate(Integer... values) {
			super.onProgressUpdate(values);
			dialog.setProgress(values[0]);
			
		}
    	
    	//后台线程
		@Override
		protected Object doInBackground(String... arg0) {
			try {
				URL url = new URL("http://10.0.2.2:8080/TestHandle/ylxb.mp3");
				HttpURLConnection connection = (HttpURLConnection) url.openConnection();
				//获取文件总长度
				int totalLength  = connection.getContentLength();
				File file = new File("/mnt/sdcard/1234.mp3");
				file.createNewFile();//创建文件
				int baifen = 0;
				//分长度
				int fen =  totalLength/5;
				int stop=0;
				for (int i = 0; i < 5; i++) {
					
					stop=(i+1)*fen;
					MyThread myThread = new MyThread(url, file,i*fen+1, stop,fen);
					
					if (i==4) {
						stop=totalLength;
					}
					
					myThread.start();
					//baifen = (int)(fen/totalLength)*100;
					//传参数给前台修改进度条
					//onProgressUpdate(baifen);
				}
				
			} catch (Exception e) {
				e.printStackTrace();
			}
			
			return null;
		}

		@Override
		protected void onPostExecute(Object result) {
			// TODO Auto-generated method stub
			super.onPostExecute(result);
			//dialog.dismiss();		//进度条消失
		}
		
    }
    
    
    class MyThread extends Thread{
    	private URL url;
    	private File file;
    	private int StartPostion;
    	private int StopPostion;
    	private int len;
    	private ProgressDialog dialog;
    	
    	public MyThread(URL url, File file, int startPostion, int stopPostion,
    			int len) {
    		super();
    		this.url = url;
    		this.file = file;
    		StartPostion = startPostion;
    		StopPostion = stopPostion;
    		this.len = len;
    	}

    	@Override
    	public void run() {
    		super.run();
    		HttpURLConnection connection;
    		try {
    			connection = (HttpURLConnection) url.openConnection();
    			
    			System.out.println(StartPostion+"----"+StopPostion);
    			
    			connection.setRequestProperty("Range", "bytes="+StartPostion+"-"+StopPostion);
    			connection.setAllowUserInteraction(true);	//允许用户采用断电分割
    			
    			InputStream inputStream = connection.getInputStream();
    			
    			
    			
    			OutputStream outputStream = new FileOutputStream(file);
    			//转换成底层流
    			BufferedInputStream inputStream1 = new BufferedInputStream(inputStream);
    			RandomAccessFile outputSteam1 = new RandomAccessFile(file, "rw");
    			outputSteam1.seek((long) StartPostion);	//一开始的位置
    			byte[] bb = new byte[1024];
    			
    			int data=0;
    			int baifen=0;
    			while((data=inputStream1.read(bb))!=-1){
    				//System.out.println(data);
    				outputSteam1.write(bb);
    				
    				Message message=new Message();
    				Bundle bun=new Bundle();
    				baifen = (int)(len/data)*100;
    				bun.putInt("jd", baifen);
    				message.setData(bun);
    				send.sendMessage(message);
    			}
    		} catch (Exception e) {
    			e.printStackTrace();
    		}
    	}
    }
    
    
    SendView send=new SendView();
    class SendView extends Handler{
    	public void handleMessage(Message msg) {
    		super.handleMessage(msg);
    		
    		Bundle bun=msg.getData();
    		int len=bun.getInt("jd");
    		dialog.setProgress(len);
    	}
    }
}
-------------------------------------------------------------------------------------------------
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.jinduntiao"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />
	<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
	<uses-permission android:name="android.permission.INTERNET"/>
	<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.jinduntiao.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>