Android 下载文件 显示进度条

<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"></uses-permission>

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;

public class FileDownProcessBarActivity extends Activity {
/** Called when the activity is first created. */
private static final String Path="http://210.30.12.1:8080/mp3/DJ.mp3";
private ProgressBar progressBar;
private TextView textView;
private Button button;
private int FileLength;
private int DownedFileLength=0;
private InputStream inputStream;
private URLConnection connection;
private OutputStream outputStream;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
progressBar=(ProgressBar) findViewById(R.id.progressBar1);
textView=(TextView) findViewById(R.id.textView2);
button=(Button) findViewById(R.id.button1);
button.setOnClickListener(new ButtonListener());
}
class ButtonListener implements OnClickListener{

@Override
public void onClick(View v) {
DownedFileLength=0;
// TODO Auto-generated method stub
Thread thread=new Thread(){
public void run(){
try {
DownFile(Path);
} catch (Exception e) {
// TODO: handle exception
}
}
};
thread.start();
}
}
private Handler handler=new Handler()
{
public void handleMessage(Message msg)
{
if (!Thread.currentThread().isInterrupted()) {
switch (msg.what) {
case 0:
progressBar.setMax(FileLength);
Log.i("文件长度----------->", progressBar.getMax()+"");
break;
case 1:
progressBar.setProgress(DownedFileLength);
int x=DownedFileLength*100/FileLength;
textView.setText(x+"%");
break;
case 2:
Toast.makeText(getApplicationContext(), "下载完成", Toast.LENGTH_LONG).show();
break;

default:
break;
}
}
}

};

private void DownFile(String urlString)
{

/*
* 连接到服务器
*/

try {
URL url=new URL(urlString);
connection=url.openConnection();
if (connection.getReadTimeout()==5) {
Log.i("---------->", "当前网络有问题");
// return;
}
inputStream=connection.getInputStream();

} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

/*
* 文件的保存路径和和文件名其中Nobody.mp3是在手机SD卡上要保存的路径，如果不存在则新建
*/
String savePAth=Environment.getExternalStorageDirectory()+"/DownFile";
File file1=new File(savePAth);
if (!file1.exists()) {
file1.mkdir();
}
String savePathString=Environment.getExternalStorageDirectory()+"/DownFile/"+"DJ.mp3";
File file =new File(savePathString);
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/*
* 向SD卡中写入文件,用Handle传递线程
*/
Message message=new Message();
try {
outputStream=new FileOutputStream(file);
byte [] buffer=new byte[1024*4];
FileLength=connection.getContentLength();
message.what=0;
handler.sendMessage(message);
while (DownedFileLength<FileLength) {
outputStream.write(buffer);
DownedFileLength+=inputStream.read(buffer);
Log.i("-------->", DownedFileLength+"");
Message message1=new Message();
message1.what=1;
handler.sendMessage(message1);
}
Message message2=new Message();
message2.what=2;
handler.sendMessage(message2);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}