android 下载进度条的实现

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android 下载进度条的实现
最近在写关于多线程下执行多任务同时下载的问题，其实就是单线程下任务下载的升级，现在把单线程下下载的进度条整理一下：
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();        }    }       }
多任务同时下载的话，就用线程池的思想去做管理，把任务加到线程池去执行，去和服务绑定然后显示下载进度。
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