GlassInteractionStateMixin<T extends StatefulWidget> mixin

State lifecycle mixin for interactive glass container widgets.

Provides isPressed, isFocused, and isHovered ValueNotifiers and their most common Listenable.merge combinations, with guaranteed disposal in dispose.

Why a mixin, not a widget?

Container item widgets in this package (GlassListTile, GlassMenuItem, _ActionSheetButton, _GlassGroupItemWidget) share the same interaction state lifecycle but have fundamentally different rendering: distinct shapes, decorations, scale effects, and external press states. A shared "wrapper widget" would accumulate all those render differences as constructor parameters, producing a God Widget.

A mixin supplies only the shared infrastructure — the ValueNotifiers and their merged Listenables — while leaving each widget's rendering exactly where it belongs: in its own build method. This mirrors how Flutter's own framework handles similar problems: SingleTickerProviderStateMixin provides a Ticker without imposing how the animation is painted; AutomaticKeepAliveClientMixin keeps a subtree alive without changing its build output.

Usage

Apply to a State subclass, then use isPressed, isFocused, or isHovered wherever you previously declared them as fields:

class _MyState extends State<MyWidget>
    with GlassInteractionStateMixin {
  @override
  Widget build(BuildContext context) {
    return GlassFocusRegion(
      isFocusedNotifier: isFocused,
      child: GestureDetector(
        onTapDown: (_) => isPressed.value = true,
        onTapUp:   (_) => isPressed.value = false,
        onTapCancel:  () => isPressed.value = false,
        child: ListenableBuilder(
          listenable: pressedAndFocused,
          builder: (context, child) {
            final highlight = isPressed.value || isFocused.value;
            return AnimatedContainer(
              duration: isPressed.value
                  ? Duration.zero
                  : const Duration(milliseconds: 150),
              color: highlight
                  ? const Color(0x1AFFFFFF)
                  : const Color(0x00000000),
              child: child,
            );
          },
          child: ...,
        ),
      ),
    );
  }
}

Do not update isFocused or isHovered directly; pass them to GlassFocusRegion via isFocusedNotifier and isHoveredNotifier and let the region manage them.