Android QScreen::grabWindow(0) & sample code Screenshot::shootScreen() fails on Android

1) The Qt provided "screenshot" sample code demonstrates the failing grabWindow() behavior seen elsewhere on multiple Android platforms (have not yet found one that it works on). QScreen::grabWindow() always returns a null bitmap on Android.  See function shootScreen() in the Qt sample code.

2) Attempts to use grabWindow() all fail on Android (Win32 works fine).

• fails on NVIDIA Shield K1 (arm) running either Android 6 or 7.
• fails on Panasonic FZ-B2D (x86) running Android 6.0.1
• fails on ACER (x86) GT-810 running Android 5.1
• fails on Juniper Systems Cedar (ARM) GT7G 7" running Android 6.0 

3 Tried various permutations of winId()'s, screen geometry rect's, default parameters to try and find something combination that works.  No joy (but it all works on Windows, not Android).

grabWindow(0)

grabWindow(QApplication:desktop()->winID());

grabWindow(QApplication.activeWindow()-winId(), rect.x(), rect.y()...).  etc...