Android View Viewgroup Invalidate Ondraw And Draw

We're trying to write our own MapView, and I'm trying to figure out how adding overlays to the mapview causes them to get drawn in other mapping APIs I've got a MapView that extend

Solution 1:

Calling invalidate on your viewgroup will force draw to run which will in turn call onDraw and then dispatchDraw. You should have a look at the view documentation here and the View source code here for more information.

Solution 2:

invalidate() has to be called from UI thread to cause onDraw(). Try to use postInvalidate() which should have the same effect as invalidate(), but works from non UI threads.