Observer4<A, B, C, D> constructor
const
Observer4<A, B, C, D> ({})
Constructs an Observer2 widget.
The listenable parameter is the first reactive variable to listen to.
The listenable2 parameter is the second reactive variable to listen to.
The listener parameter is a callback function that defines the widget to rebuild whenever either of the reactive variables changes.
Implementation
const Observer4({
Key? key,
required this.listenable,
required this.listenable2,
required this.listenable3,
required this.listenable4,
required this.listener,
}) : super(key: key);