Android&多线程下载

FileDownloadThread.java 
 1 package com.zachary.mutildownloader;
 2 
 3 import java.io.BufferedInputStream;
 4 import java.io.File;
 5 import java.io.IOException;
 6 import java.io.RandomAccessFile;
 7 import java.net.URL;
 8 import java.net.URLConnection;
 9 
10 import android.util.Log;
11 
12 public class FileDownloadThread extends Thread {
13     private static final int BUFFER_SIZE = 1024;
14     private URL url;
15     private File file;
16     private int startPosition;
17     private int endPosition;
18     private int curPosition;
19     //用于标示当前线程是否下载完成
20     private boolean finished = false;
21     private int downloadSize = 0;
22     
23     final static String TAG = "LOGCAT";
24     
25     public FileDownloadThread(URL url, File file, int startPosition, int endPosition){
26         this.url = url;
27         this.file = file;
28         this.startPosition = startPosition;
29         this.curPosition = startPosition;
30         this.endPosition = endPosition;
31     }
32 
33     @Override
34     public void run() {
35         // TODO Auto-generated method stub
36         BufferedInputStream bis = null;
37         RandomAccessFile fos = null;
38         byte[] buf = new byte[BUFFER_SIZE];
39         URLConnection con = null;
40         try {
41             con = url.openConnection();
42             con.setAllowUserInteraction(true);
43             Log.i(TAG, "con.setAllowUserInteraction(true);");
44             //设置当前线程下载的起点，终点
45             con.setRequestProperty("Range", "bytes=" + startPosition + "-" + endPosition);
46             
47             //使用java中的RandomAccessFile 对文件进行随机读写操作
48             fos = new RandomAccessFile(file, "rw");
49             //设置开始写文件的位置  
50             fos.seek(startPosition);
51             bis = new BufferedInputStream(con.getInputStream());
52             //开始循环以流的形式读写文件  
53             while(curPosition < endPosition) {
54                 int len = bis.read(buf, 0, BUFFER_SIZE);
55                 if(len == -1)
56                     break;
57                 fos.write(buf, 0, len);
58                 curPosition = curPosition + len;
59                 if(curPosition > endPosition){
60                     downloadSize += len - (curPosition - endPosition) + 1;
61                 }else {
62                     downloadSize += len;
63                 }
64             }
65             this.finished = true;
66             Log.i(TAG, "the thread was finished");
67             bis.close();
68             fos.close();
69         } catch (IOException e) {
70             // TODO Auto-generated catch block
71             e.printStackTrace();
72             Log.d(getName() +" Error:", e.getMessage());  
73         }
74     }
75     
76     public boolean isFinished() {
77         return finished;
78     }
79     
80     public int getDownloadSize() {
81         return downloadSize;
82     }
83 }
MainActivity.java 
  1 package com.zachary.mutildownloader;
  2 
  3 import java.io.File;
  4 import java.io.IOException;
  5 import java.net.MalformedURLException;
  6 import java.net.URL;
  7 import java.net.URLConnection;
  8 
  9 import android.app.Activity;
 10 import android.os.Bundle;
 11 import android.os.Environment;
 12 import android.os.Handler;
 13 import android.os.Message;
 14 import android.util.Log;
 15 import android.view.Menu;
 16 import android.view.View;
 17 import android.view.View.OnClickListener;
 18 import android.widget.Button;
 19 import android.widget.ProgressBar;
 20 import android.widget.TextView;
 21 import android.widget.Toast;
 22 
 23 public class MainActivity extends Activity {
 24     
 25     private Button downloadBtn = null;
 26     private ProgressBar downloadProgressBar = null;
 27     private TextView myTextView = null;
 28     private int downloadedSize = 0;
 29     private int fileSize = 0;
 30     
 31     final static String TAG = "LOGCAT";
 32     
 33     @Override
 34     protected void onCreate(Bundle savedInstanceState) {
 35         super.onCreate(savedInstanceState);
 36         setContentView(R.layout.activity_main);
 37         
 38         downloadBtn = (Button)findViewById(R.id.downloadButton);
 39         downloadProgressBar = (ProgressBar)findViewById(R.id.downloadBar);
 40         myTextView = (TextView)findViewById(R.id.myTextView);
 41         downloadProgressBar.setVisibility(View.VISIBLE);
 42         downloadProgressBar.setProgress(0);
 43         
 44         downloadBtn.setOnClickListener(new OnClickListener() {
 45 
 46             @Override
 47             public void onClick(View arg0) {
 48                 // TODO Auto-generated method stub
 49                 String urlStr = "http://zhangmenshiting.baidu.com/data2/music/35420301/35420301.mp3?xcode=54e756b52270bf9f05efbff149ebffea&mid=0.05505464576834";
 50                 download(urlStr);
 51             }
 52             
 53         });
 54         
 55     }
 56     
 57     private void download(String urlStr){
 58         String downloadDir = Environment.getExternalStorageDirectory() + "/myDownload/";
 59         File file = new File(downloadDir);
 60         if(!file.exists()){
 61             file.mkdirs();
 62             Toast.makeText(MainActivity.this,"make the Dir", Toast.LENGTH_LONG).show();
 63         }
 64         String fileName = "abc.mp3";
 65         downloadBtn.setClickable(false);
 66         downloadProgressBar.setProgress(0);
 67         new downloadTask(urlStr, 5, downloadDir + fileName).start();
 68         Log.i(TAG,"Begin to download");
 69     }
 70     
 71     
 72     Handler handler = new Handler() {  
 73         @Override  
 74         public void handleMessage(Message msg) {  
 75             //当收到更新视图消息时，计算已完成下载百分比，同时更新进度条信息  
 76             int progress = (Double.valueOf((downloadedSize * 1.0 / fileSize * 100))).intValue();  
 77             if (progress == 100) {  
 78                 downloadBtn.setClickable(true);  
 79                 myTextView.setText("下载完成！");  
 80             } else {  
 81                 myTextView.setText("当前进度:" + progress + "%");  
 82             }  
 83             downloadProgressBar.setProgress(progress);  
 84         }  
 85    
 86     };  
 87     
 88     //主下载线程 
 89     public class downloadTask extends Thread{
 90         private int blockSize, downloadSizeMore;
 91         private int threadNum = 5;
 92         String urlStr, threadNo, fileName;
 93         public downloadTask(String urlStr, int threadNum, String fileName){
 94             this.urlStr = urlStr;
 95             this.threadNum = threadNum;
 96             this.fileName = fileName;
 97             Log.i(TAG,"downloadTask" + fileName);
 98         }
 99         
100         
101         @Override
102         public void run() {
103             FileDownloadThread[] fds = new FileDownloadThread[threadNum];
104             try {
105                 URL url = new URL(urlStr);
106                 URLConnection conn = url.openConnection();
107                 //获取下载文件的总大小  
108                 fileSize = conn.getContentLength();
109                 //计算每个线程要下载的数据量
110                 blockSize = fileSize / threadNum;
111                 downloadSizeMore = (fileSize % threadNum) ;
112                 File file = new File(fileName);
113                 for(int i = 0; i < threadNum; i++ ) {
114                      //启动线程，分别下载自己需要下载的部分  
115                     
116                     FileDownloadThread fdt = new FileDownloadThread(url, file, i*blockSize, (i+1)*blockSize - 1);
117                     System.out.println("FileDownloadThread---->" + i);
118                     Log.i(TAG,"FileDownloadThread---->" + i);
119                     fdt.setName("Thread" + i);
120                     fdt.start();
121                     fds[i] = fdt;
122                 }
123                 
124                 
125                 boolean finished = false;
126                 while(!finished) {
127                      // 先把整除的余数搞定
128                     downloadedSize = downloadSizeMore;
129                     finished = true;
130                     for(int i=0; i < fds.length; i++){
131                         downloadedSize += fds[i].getDownloadSize();
132                         if(!fds[i].isFinished()){
133                             finished = false;
134                         }
135                         
136                     }
137                     handler.sendEmptyMessage(0);
138                     sleep(1000);
139                 }
140             } catch (MalformedURLException e) {
141                 // TODO Auto-generated catch block
142                 e.printStackTrace();
143             } catch (IOException e) {
144                 // TODO Auto-generated catch block
145                 e.printStackTrace();
146             } catch (InterruptedException e) {
147                 // TODO Auto-generated catch block
148                 e.printStackTrace();
149             }
150         }
151         
152     }
153     
154     
155     @Override
156     public boolean onCreateOptionsMenu(Menu menu) {
157         // Inflate the menu; this adds items to the action bar if it is present.
158         getMenuInflater().inflate(R.menu.main, menu);
159         return true;
160     }
161 
162 }
activity_main.xml 
 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:paddingBottom="@dimen/activity_vertical_margin"
 6     android:paddingLeft="@dimen/activity_horizontal_margin"
 7     android:paddingRight="@dimen/activity_horizontal_margin"
 8     android:paddingTop="@dimen/activity_vertical_margin"
 9     tools:context=".MainActivity"
10     android:orientation="vertical" >
11 
12     <Button
13         android:layout_width="fill_parent"
14         android:layout_height="wrap_content"
15         android:text="Download" 
16         android:id="@+id/downloadButton"/>
17     <ProgressBar
18         android:id="@+id/downloadBar"
19          android:layout_width="200dp"
20          android:layout_height="40dp"
21          style="?android:attr/progressBarStyleHorizontal"
22          android:visibility="gone"
23          android:max="100"
24          android:layout_gravity="center_vertical"/>
25     <TextView
26         android:id="@+id/myTextView"
27         android:layout_width="fill_parent"
28         android:layout_height="wrap_content"/>
29 </LinearLayout>

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

posted on 2013-04-18 21:03  Zachary_wiz  阅读(163)  评论(0)  编辑  收藏  举报

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