Android AsyncTask将讲解

 1 new AsyncTask<String, Void, String>() {
 2 
 3             @Override
 4             protected void onCancelled() {
 5                 // TODO Auto-generated method stub
 6                 super.onCancelled();
 7             }
 8 
 9             @Override
10             protected void onCancelled(String result) {
11                 // TODO Auto-generated method stub
12                 super.onCancelled(result);
13             }
14 
15             @Override
16             protected void onPostExecute(String result) {
17                 super.onPostExecute(result);
18                 text.setText(result);
19             }
20 
21             @Override
22             protected void onPreExecute() {
23                 Toast.makeText(MainActivity.this, "开始读取", Toast.LENGTH_SHORT).show();
24                 super.onPreExecute();
25             }
26 
27             @Override
28             protected void onProgressUpdate(Void... values) {
29                 // TODO Auto-generated method stub
30                 super.onProgressUpdate(values);
31             }
32 
33             @Override
34             protected String doInBackground(String... params) {
35                 URL url;
36                 try {
37                     url = new URL(params[0]);
38                     URLConnection conn = url.openConnection();
39                     InputStream is = conn.getInputStream();
40                     InputStreamReader isr = new InputStreamReader(is);
41                     BufferedReader br = new BufferedReader(isr);
42                     String line;
43                     StringBuilder builder = new StringBuilder();
44                     while ((line = br.readLine()) != null) {
45                         builder.append(line);
46                     }
47                     br.close();
48                     is.close();
49                     return builder.toString();
50                 } catch (IOException e) {
51                     e.printStackTrace();
52                 }
53                 return null;
54             }
55             
56         }.execute(url);