Two AsyncTasks cannot update screen simultaneously

Question

I have two asynctasks. One of them is updating the part of title bar every second. After I start other asynctask(which updates other screen element every second as well), first one still runs, but cannot update screen. I call UI stuff on onProgressUpdate() .No exception is thrown. All works fine in separate. Problems only when ocur concurent. I do not understand why. I do use API 8 (FROYO).

Thank You.

http://stackoverflow.com/questions/4068984/running-multiple-asynctasks-at-the-same-time-not-possible — Matt Wolfe, Apr 05 '13 at 15:22

score 1 · Answer 1 · edited May 23 '17 at 12:13

1

When first introduced, AsyncTasks were executed serially on a single background thread. Starting with DONUT, this was changed to a pool of threads allowing multiple tasks to operate in parallel. Starting with HONEYCOMB, tasks are executed on a single thread to avoid common application errors caused by parallel execution.

If you truly want parallel execution, you can invoke executeOnExecutor(java.util.concurrent.Executor, Object[]) with THREAD_POOL_EXECUTOR.

For more information have a look at the link below.

http://developer.android.com/reference/android/os/AsyncTask.html

https://github.com/vitkhudenko/test_asynctask. A sample of asynctask to test and play with

As an alternative you can use RoboSpice. Can handle multiple spice requests. https://github.com/octo-online/robospice

Edit: Check the link below there is a good explanation regarding the topic.

Running multiple AsyncTasks at the same time -- not possible?

void startMyTask(AsyncTask asyncTask) {
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
    asyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, params);
else
    asyncTask.execute(params);
 }

http://developer.android.com/reference/java/util/concurrent/Executor.html

edited May 23 '17 at 12:13

Community

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answered Apr 05 '13 at 15:24

Raghunandan

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Thank You for Your answer. But I Use FROYO-whitch is in between Donut and Honeycomb – Balvonas Apr 05 '13 at 15:30
+1 Superb description. – Paresh Mayani Apr 05 '13 at 15:33
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@PareshMayani thank you. Straight from the documentation. But i did look for details in SO especially the link for asynctask test sample. Probably need to be more descriptive of robospice. – Raghunandan Apr 05 '13 at 15:35
have you tried using executeOnExecutor? – Matt Wolfe Apr 05 '13 at 15:37
nope i have not tried it – Raghunandan Apr 05 '13 at 15:41
please read My question again!! You would be answering to similar question if I wouldn't be using FROYO. – Balvonas Apr 06 '13 at 11:05
post some code. if not me others can help you. – Raghunandan Apr 06 '13 at 14:32

Two AsyncTasks cannot update screen simultaneously

1 Answers1