1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:layout_width="fill_parent" 4 android:layout_height="fill_parent" 5 android:orientation="vertical" > 6 7 <TextView 8 android:layout_width="fill_parent" 9 android:layout_height="wrap_content" 10 android:text="@string/down_load" /> 11 12 <EditText 13 android:id="@+id/et" 14 android:layout_width="fill_parent" 15 android:layout_height="wrap_content" 16 android:hint="@string/hint" 17 android:text="http://192.168.1.247:8080/youdao.exe" /> 18 19 <ProgressBar 20 android:id="@+id/pb" 21 style="?android:attr/progressBarStyleHorizontal" 22 android:layout_width="fill_parent" 23 android:layout_height="wrap_content" /> 24 25 <TextView 26 android:id="@+id/tv_process" 27 android:layout_width="fill_parent" 28 android:layout_height="wrap_content" /> 29 30 <Button 31 android:id="@+id/bt" 32 android:layout_width="fill_parent" 33 android:layout_height="wrap_content" 34 android:text="@string/download" /> 35 36 </LinearLayout>
1 /** 2 * 49_多线程断点下载的实现&界面的更新 DEMO 3 * @author dr 4 * 5 */ 6 public class DemoActivity extends Activity implements OnClickListener { 7 8 private ProgressBar pb; 9 private Button bt; 10 private TextView tv; 11 private EditText et; 12 boolean flag = true; 13 boolean stopflag = false; 14 int total = 0; 15 16 private Handler handler = new Handler() { 17 18 @Override 19 public void handleMessage(Message msg) { 20 pb.setProgress(total); 21 // 文件总长度 22 int max = pb.getMax(); 23 // total和max都是从0开始的。 24 if (total >= (max - 1)) { 25 total = max; 26 flag = false; 27 } 28 int result = total * 100 / max; 29 tv.setText("当前进度 :" + result + "%"); 30 31 super.handleMessage(msg); 32 } 33 }; 34 35 @Override 36 public void onCreate(Bundle savedInstanceState) { 37 super.onCreate(savedInstanceState); 38 setContentView(R.layout.main); 39 pb = (ProgressBar) this.findViewById(R.id.pb); 40 bt = (Button) this.findViewById(R.id.bt); 41 tv = (TextView) this.findViewById(R.id.tv_process); 42 et = (EditText) this.findViewById(R.id.et); 43 bt.setOnClickListener(this); 44 45 } 46 47 @Override 48 public void onClick(View v) { 49 switch (v.getId()) { 50 case R.id.bt: 51 // 创建一个子线程 定期的更新ui 52 if ("开始下载".equals(bt.getText().toString())) { 53 bt.setText("暂停"); 54 stopflag = false; // 开始下载 55 } else { 56 bt.setText("开始下载"); 57 stopflag = true; 58 } 59 new Thread() { 60 @Override 61 public void run() { 62 super.run(); 63 while (flag) { 64 try { 65 sleep(1000); 66 // 如果total > = 文件长度 67 Message msg = new Message(); 68 handler.sendMessage(msg); 69 } catch (InterruptedException e) { 70 e.printStackTrace(); 71 } 72 } 73 } 74 }.start(); 75 76 // 开始执行下载的操作 77 String path = et.getText().toString().trim(); 78 if ("".equals(path)) { 79 Toast.makeText(this, "路径不能为空", 1).show(); 80 return; 81 } 82 try { 83 URL url = new URL(path); 84 HttpURLConnection conn = (HttpURLConnection) url 85 .openConnection(); 86 conn.setRequestMethod("GET"); 87 conn.setConnectTimeout(5000); 88 conn.setRequestProperty("User-Agent", 89 "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"); 90 int code = conn.getResponseCode(); 91 if (code == 200) { 92 int len = conn.getContentLength(); 93 RandomAccessFile file = new RandomAccessFile("/mnt/sdcard/" 94 + getFilenName(path), "rwd"); 95 // 1.设置本地文件大小跟服务器的文件大小一致 96 file.setLength(len); 97 // 设置进度条的最大值 98 pb.setMax(len); 99 100 // 2 .假设开启3 个线程 101 int threadnumber = 3; 102 int blocksize = len / threadnumber; 103 /** 104 * 线程1 0~ blocksize 线程2 1*bolocksize ~ 2*blocksize 线程3 105 * 2*blocksize ~ 文件末尾 106 */ 107 for (int i = 0; i < threadnumber; i++) { 108 int startposition = i * blocksize; 109 int endpositon = (i + 1) * blocksize; 110 if (i == (threadnumber - 1)) { 111 // 最后一个线程 112 endpositon = len; 113 } 114 115 DownLoadTask task = new DownLoadTask(i, path, 116 startposition, endpositon); 117 task.start(); 118 } 119 120 } 121 } catch (Exception e) { 122 Toast.makeText(this, "下载出现异常", 0).show(); 123 e.printStackTrace(); 124 } 125 126 break; 127 } 128 129 } 130 131 class DownLoadTask extends Thread { 132 133 int threadid; 134 String filepath; 135 int startposition; 136 int endpositon; 137 138 public DownLoadTask(int threadid, String filepath, int startposition, 139 int endpositon) { 140 this.threadid = threadid; 141 this.filepath = filepath; 142 this.startposition = startposition; 143 this.endpositon = endpositon; 144 145 } 146 147 @Override 148 public void run() { 149 try { 150 File postionfile = new File("/mnt/sdcard/" + threadid + ".txt"); 151 URL url = new URL(filepath); 152 HttpURLConnection conn = (HttpURLConnection) url 153 .openConnection(); 154 System.out.println("线程" + threadid + "正在下载 " + "开始位置 : " 155 + startposition + "结束位置 " + endpositon); 156 157 if (postionfile.exists()) { 158 FileInputStream fis = new FileInputStream(postionfile); 159 byte[] result = StreamTool.getBytes(fis); 160 String str = new String(result); 161 if (!"".equals(str)) { 162 int newstartposition = Integer.parseInt(str); 163 if (newstartposition > startposition) { 164 startposition = newstartposition; 165 } 166 } 167 } 168 169 // "Range", "bytes=2097152-4194303") 170 conn.setRequestProperty("Range", "bytes=" + startposition + "-" 171 + endpositon); 172 conn.setRequestMethod("GET"); 173 conn.setConnectTimeout(5000); 174 conn.setRequestProperty("User-Agent", 175 "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1)"); 176 InputStream is = conn.getInputStream(); 177 RandomAccessFile file = new RandomAccessFile("/mnt/sdcard/" 178 + getFilenName(filepath), "rwd"); 179 // 设置 数据从文件哪个位置开始写 180 file.seek(startposition); 181 byte[] buffer = new byte[1024]; 182 int len = 0; 183 // 代表当前读到的服务器数据的位置 ,同时这个值已经存储的文件的位置 184 int currentPostion = startposition; 185 // 创建一个文件对象 ,记录当前某个文件的下载位置 186 187 while ((len = is.read(buffer)) != -1) { 188 if (stopflag) { // 暂停下载 189 return; 190 } 191 file.write(buffer, 0, len); 192 193 synchronized (DemoActivity.this) { // 同步当前的 194 total += len; 195 } 196 197 currentPostion += len; 198 // 需要把currentPostion 信息给持久化到存储设备 199 String position = currentPostion + ""; 200 FileOutputStream fos = new FileOutputStream(postionfile); 201 fos.write(position.getBytes()); 202 fos.flush(); 203 fos.close(); 204 } 205 206 file.close(); 207 System.out.println("线程" + threadid + "下载完毕"); 208 // 当线程下载完毕后 把文件删除掉 209 if (postionfile.exists()) { 210 postionfile.delete(); 211 } 212 } catch (Exception e) { 213 e.printStackTrace(); 214 } 215 super.run(); 216 } 217 } 218 219 public String getFilenName(String path) { 220 int start = path.lastIndexOf("/") + 1; 221 return path.substring(start, path.length()); 222 } 223 }
1 public class StreamTool { 2 /** 3 * 把一个inputstream里面的内容转化成一个byte[] 4 */ 5 public static byte[] getBytes(InputStream is) throws Exception{ 6 ByteArrayOutputStream bos = new ByteArrayOutputStream(); 7 byte[] buffer = new byte[1024]; 8 int len = 0; 9 while((len = is.read(buffer))!=-1){ 10 bos.write(buffer, 0, len); 11 } 12 is.close(); 13 bos.flush(); 14 byte[] result = bos.toByteArray(); 15 System.out.println(new String(result)); 16 return result; 17 } 18 }
1 <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> 2 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> 3 <uses-permission android:name="android.permission.INTERNET"/>