How to raise a toast in AsyncTask, I am prompted to used the Looper

Question

I have tasks completed by AsyncTask in background. At some point I need to issue a Toast that something is completed.

I've tried and I failed because Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

How can I do that?

Answer 1

onPostExecute - executes on UI thread or publishProgress(); in your doinbackground and

protected void onProgressUpdate(Integer... progress) {
}

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

Answer 2

You can also use runOnUiThread method to manipulate your UI from background threads.

Answer 3

If you want to display the Toast from the background thread you'll have to call runOnUiThread from doInBackground. I don't believe there's another way.

Edit: I take that back. I think you can implement onProgressUpdate, which runs on the UI thread, to show the Toast and make calls to publishProgress from doInBackground.