I'm developing a custom keyboard which has an overridden OnDraw() for both the view container itself and it's child key views. I'm also using SetWillNotDraw(false) appropriately for each view. It currently works beautifully in 5.0.1 on my Nexus 10 tablet.
In Android 6.0.1, on a Nexus 6 and a Nexus 6P, the keyboard view correctly draws itself (just a background color). The child key views however are never drawn, even if I iterate through the view hierarchy and force an invalidate on each one. This seems to be specific to Marshmallow.
I don't know if there's something new I need to account for in this version of Android or if I'm encountering a bug.
Has anyone else encountered any new issues with custom drawing?