android学习笔记3-文件下载

<uses-permission android:name="android.permission.CHANGE_NETWORK_STATE" >    </uses-permission>    <uses-permission android:name="android.permission.CHANGE_WIFI_STATE" >    </uses-permission>    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" >    </uses-permission>    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" >    </uses-permission>    <uses-permission android:name="android.permission.INTERNET" >    </uses-permission>    <uses-permission android:name="android.permission.WAKE_LOCK" >    </uses-permission>    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

获得手机的权限，包括网络和读写SD卡的权限

package com.example.testdownfile;import android.os.Bundle;import android.app.Activity;import android.view.Menu;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.EditText;import android.widget.ProgressBar;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity {    /** Called when the activity is first created. http://www.open-open.com/lib/view/open1328973152812.html*///private static final String Path="http://p.baidupcs.com/file/8a021c919e4d146226c743ca683b5968?fid=3088732464-250528-651295825860462&time=1401080944&sign=FDTAXER-DCb740ccc5511e5e8fedcff06b081203-%2F6lRviANdxZw7XyJH1NqM2AXTDI%3D&to=pb&fm=N,B,G,e&newver=1&expires=1401081544&rt=sh&r=733120661&logid=1054769191&sh=1&vuk=3088732464&fn=Angelis-Angel.mp3";private static final String Path="http://210.30.100.2/Office2010.rar";private ProgressBar progressBar;//下载进度条private TextView textView;private TextView textView2;private EditText ipText;private Button button;private long FileLength;//文件总长度private long DownedFileLength=0;private InputStream inputStream;private URLConnection connection;private OutputStream outputStream;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        progressBar=(ProgressBar) findViewById(R.id.progressBar1);           textView=(TextView) findViewById(R.id.textView1);        textView2=(TextView) findViewById(R.id.textView2);        button=(Button) findViewById(R.id.button1);        button.setOnClickListener(new ButtonListener());    }    class ButtonListener implements OnClickListener{@Overridepublic 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()//根据当前已下载文件大小刷新进度条    {     public void handleMessage(Message msg)     {if (!Thread.currentThread().isInterrupted()) {switch (msg.what) {case 0:progressBar.setMax(100);textView2.setText("文件大小:"+FileLength/1024/1024+"M");Log.i("文件长度----------->", progressBar.getMax()+"");break;case 1:int x=(int) (DownedFileLength*100/FileLength);progressBar.setProgress(x);System.out.println("x----->"+x);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();//打来连接 if (connection.getReadTimeout()==5) {Log.i("---------->", "当前网络有问题");// return;   } inputStream=connection.getInputStream();} catch (MalformedURLException e1) {// TODO Auto-generated catch blocke1.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.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()+"/download";System.out.println("path----->"+savePAth);File file1=new File(savePAth);if (!file1.exists()) {    file1.mkdir();}String savePathString=Environment.getExternalStorageDirectory()+"/download"+"/office.rar";File file =new File(savePathString);if (!file.exists()) {try {file.createNewFile();} catch (IOException e) {// TODO Auto-generated catch blocke.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();System.out.println("fileLength----->"+FileLength);message.what=0;handler.sendMessage(message);while (DownedFileLength<FileLength) {outputStream.write(buffer);    DownedFileLength+=inputStream.read(buffer);    System.out.println("DownedFileLength------>"+DownedFileLength);    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 blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}    }      }