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I have an application and because you can't do network operations on the main thread I'm using AsyncTask, so the question is once I execute() the AsyncTask and right after that I finish() the activity, and maybe the user will finish() the whole app, so what I'm wondering is:
AsyncTask always finish doInBackground() and onPostExecute() even if the app is closed as long as execute() was called when the app was running?
459
onPostExecute() is called from the UI thread - so if the UI thread is no longer running, it will not continue to run. However doInBackGround() is ran from a separate worker thread so it will keep on until done (or if the JVM process is killed by the OS, which is also a possibility). Note that AsyncTasks are only recommended for shorter UI-bound background tasks and not long-running background work (a few seconds).
In short, you can not assume that it will keep on and definitely not assume that it will post its progress or call onPostExecute().
29
You will be able to test this. And yes It does. If execute was called you can see Asynctask will still execute UNLESS it does something to the forground or UI related. (it may cause launcher to crash).
However, if it was close by the system. It may or may not continue executing the method. I have already tested and answered here.
Reply to comment:
Tested:
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Worker().execute();
}
private class Worker extends AsyncTask<Void, Void, String> {
@Override
protected String doInBackground(Void... arg0) {
Log.i("SomeTag",
"start do in background at " + System.currentTimeMillis());
String data = null;
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(
"https://stackoverflow.com/questions/tagged/android");
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
data = EntityUtils.toString(httpEntity);
Log.i("SomeTag",
"doInBackGround done at " + System.currentTimeMillis());
} catch (Exception e) {
}
return data;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Log.i("SomeTag", System.currentTimeMillis() / 1000L
+ " post execute \n" + result);
}
}
@Override
protected void onDestroy() {
super.onDestroy();
Log.i("SomeTag", System.currentTimeMillis() / 1000L + " onDestory()");
}
04-24 21:42:57.981: I/SomeTag(5961): start do in background at 1366854177994
04-24 21:43:00.974: I/SomeTag(5961): 1366854180 onDestory()
04-24 21:43:02.946: I/SomeTag(5961): doInBackGround done at 1366854182946
04-24 21:43:02.946: I/SomeTag(5961): 1366854182 post execute
04-24 21:43:02.946: I/SomeTag(5961): <!DOCTYPE html>
04-24 21:43:02.946: I/SomeTag(5961): <html>
04-24 21:43:02.946: I/SomeTag(5961): <head>
04-24 21:43:02.946: I/SomeTag(5961):
04-24 21:43:02.946: I/SomeTag(5961): <title>Newest 'android' Questions - Stack Overflow</title>
04-24 21:43:02.946: I/SomeTag(5961): <link rel="shortcut icon" href="http://cdn.sstatic.net/stackoverflow/img/favicon.ico">
//....
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