我使用AsyncTask編寫了一個關于JSON解析的簡單代碼。我隻是在TextView中顯示回複。我不知道這是對還是錯。它在GingerBread上工作并在JellyBean上顯示NetworkOnMainThreadException。如果我使用StrictMode，它将在JellyBean上工作并在GingerBread上關閉力量。如何編寫支援Android 3.0及以上Android 3.0的代碼。
public class MainActivity extends Activity {
TextView tv;
Button b;
InputStream is = null;
DefaultHttpClient client;
HttpGet get;
HttpResponse response;
HttpEntity entity;
StringBuffer buffer;
@SuppressLint("NewApi")
@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
// StrictMode.setThreadPolicy(policy);
tv = (TextView) findViewById(R.id.texty);
b = (Button) findViewById(R.id.buttonGET);
b.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MyOperation mytask = new MyOperation();
mytask.execute();
}
});
}
private class MyOperation extends AsyncTask {
ProgressDialog dialog = new ProgressDialog(MainActivity.this);
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
dialog.setMessage("Loading...");
dialog.show();
}
@Override
protected String doInBackground(String... params) {
// TODO Auto-generated method stub
client = new DefaultHttpClient();
get = new HttpGet("http://www.google.com");
try {
response = client.execute(get);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
entity = response.getEntity();
try {
is = entity.getContent();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
dialog.dismiss();
BufferedReader reader = new BufferedReader(
new InputStreamReader(is));
StringBuffer buffer = new StringBuffer();
String line = null;
do {
try {
line = reader.readLine();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
buffer.append(line);
} while (line != null);
tv.setText(buffer);
}
}
}