Question

Can somebody please explain how android.app.ProgressDialog is properly used. Since, when I call hide() method, it says Only the thread which created the ui can touch it. But dismiss() method removed the progress dialog. But after dismiss() method, calling show() does not properly show the progress dialog.

Answer 1

Do not use hide() or dismiss() outside UI thread. You must invoke these methods in UI thread.
To hide dialog from non UI thread you can use View.post if you have any view or Activity.runInUiThread.

More better use onPostExecute or onCancel for AsyncTask class. Or Handler as a general approach.