BusyOverlay Class

Detailed Description

BusyOverlay is intended to be installed as a child of a container widget (typically ActivityStack). When shown, it covers the parent completely with an opaque background, displays a centered spinner and a label, and swallows all pointer/keyboard input so the user cannot fire duplicate navigations while a synchronous operation (e.g. lazy activity instantiation, shader compilation) is in flight.

The overlay auto-resizes to match its parent via event filter.

BusyOverlay* overlay = new BusyOverlay(stack);
overlay->showBusy(tr("Loading Construct…"));
// ... synchronous work, but call processEvents() first to paint ...
overlay->hideBusy();