VisibilityDetector constructor

const VisibilityDetector({
  1. required Key key,
  2. required Widget child,
  3. required VisibilityChangedCallback? onVisibilityChanged,
})

Constructor.

key is required to properly identify this widget; it must be unique among all VisibilityDetector and SliverVisibilityDetector widgets.

onVisibilityChanged may be null to disable this VisibilityDetector.

Implementation

const VisibilityDetector({
  required Key key,
  required Widget child,
  required this.onVisibilityChanged,
})  : assert(key != null),
      assert(child != null),
      super(key: key, child: child);