20 February 2017
tags:
Android
java
lesson learnt the hard way
lessons learnt the hard way
programming
AsyncTask: update UI Thread:
doInBackground() does not interact with UI thread, even if you invoke
runOnUIThread()
runnable. It will just throw an error.
To update UI, do runOnUIThread in onPostExecute or onProgressUpdate
In order to access files outside the sandbox (e.g. on internal/external storage), you need to explicitly state it in AndroidManifest.xml. Otherwise, an error (EACCESS) will be thrown.
This one is a bit cryptic: when you redraw UI elements, if element A overlaps with element B even just slightly, the one that’s drawn latest will be shown, and the one that’s drawn first will be completely invisible. Just avoid overlapping UI elements I guess.