Shows a SnackBar at the bottom of the scaffold.
A scaffold can show at most one snack bar at a time. If this function is called while another snack bar is already visible, the given snack bar will be added to a queue and displayed after the earlier snack bars have closed.
To control how long a SnackBar remains visible, use SnackBar.duration.
To remove the SnackBar with an exit animation, use hideCurrentSnackBar or call ScaffoldFeatureController.close on the returned ScaffoldFeatureController. To remove a SnackBar suddenly (without an animation), use removeCurrentSnackBar.
See Scaffold.of for information about how to obtain the ScaffoldState.
Source
ScaffoldFeatureController<SnackBar, SnackBarClosedReason> showSnackBar(SnackBar snackbar) {
_snackBarController ??= SnackBar.createAnimationController(vsync: this)
..addStatusListener(_handleSnackBarStatusChange);
if (_snackBars.isEmpty) {
assert(_snackBarController.isDismissed);
_snackBarController.forward();
}
ScaffoldFeatureController<SnackBar, SnackBarClosedReason> controller;
controller = new ScaffoldFeatureController<SnackBar, SnackBarClosedReason>._(
// We provide a fallback key so that if back-to-back snackbars happen to
// match in structure, material ink splashes and highlights don't survive
// from one to the next.
snackbar.withAnimation(_snackBarController, fallbackKey: new UniqueKey()),
new Completer<SnackBarClosedReason>(),
() {
assert(_snackBars.first == controller);
hideCurrentSnackBar(reason: SnackBarClosedReason.hide);
},
null // SnackBar doesn't use a builder function so setState() wouldn't rebuild it
);
setState(() {
_snackBars.addLast(controller);
});
return controller;
}