Ignore Parent View Background?

In the real world, the example control panel layout (below) appears within its own FrameLayout (Fragment container) and (depending on whether the app is running on a tablet) alongs

Solution 1:

A better question would have been:

How do I combine the alpha-255 background color of the map with any other colour to produce a new alpha-255 color which can then be applied to the control panel button such that the appearance of the control panel button perfectly corresponds to the map, irrespective of control panel background?

So far, so good! (See android.support.v4.graphics.ColorUtils)

colorBtn.setBackgroundColor(ColorUtils.compositeColors(pickedColor, mapBackgroundColor);

See here for the doco. The source wasn't in my SDK. I had to get it here.