Android CountDownLatch.await() freezes UI prematurely

Question

So I am running some threads with a CountDownLatch.

My problem is that when I call latch.await() the UI seems to hang and even UI commands that were called beforehand have no effect. e.g.

btnShare.setVisibility(View.INVISIBLE);
prgSharing.setVisibility(View.VISIBILE);

latch.await()

The first two lines have no effect on the UI.

Any idea why this is and possibly a solution? Thanks.

score 3 · Accepted Answer · answered Oct 22 '12 at 14:46

3

This is most likely because you are blocking the UI-Thread before it can render the Views again. I think you should look at AsyncTask and maybe put your wait logic in the doInBackground() method, or somehow re-think your implementation.

answered Oct 22 '12 at 14:46

Ovidiu Latcu

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Good idea, in my UI Thread I am processing the multiple web tasks but offload this to a AsyncTask where I can then await() for the two to finish and pass the final result back to the UI Thread. Thanks. – jim Oct 22 '12 at 14:56

score 2 · Answer 2 · answered Oct 22 '12 at 14:47

2

if the UI hangs it is because you call:

latch.await()

on the UI Thread. You have to avoid blocking call on the UI Thread since those are the cause of ANR

answered Oct 22 '12 at 14:47

Blackbelt

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Android CountDownLatch.await() freezes UI prematurely

2 Answers2