android AsyncTask development
some points about android AsyncTask
Here is something you need to pay attention when accessing Internet in your android APP as it will lead to NetworkNotFound exception if not followed what mentioned next:
- All know we have to add Internet permission in Manifest XML
Add function which need Internet access into a class extends AsyncTask, so that it can work properly.
BTW: AsyncTask is an internal android class you can import it easily.here attached an example which is load a picture on Internet:
private class LoadPic extends
AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... url) {
String returnIt=null;
URL myFileUrl = null;
try {
myFileUrl = new URL(photourl);
}catch (MalformedURLException e) {
e.printStackTrace();
}
try {
HttpURLConnection conn = (HttpURLConnection) myFileUrl.openConnection();
conn.setDoInput(true);
conn.setUseCaches(false);
conn.connect();
InputStream is = conn.getInputStream();
bitmap = BitmapFactory.decodeStream(is);
is.close();
Log.d("loadPic",returnIt);
return returnIt;
} catch (Exception e) {
System.err.println(e);
return null;
}
}
@Override
protected void onPostExecute(String result) {
try {
ImageView connectionPic=(ImageView) findViewById(R.id.postpic);
connectionPic.setImageBitmap(bitmap);
}catch (Exception e) {
System.err.println(e);
}
}some other tips for myself: .split('$') will not work, modified it to .split('\$'). It seems that "$" is one of restricted words in JAVA
end. 2014-04-17