restorablePushNamed<T extends Object?> method Null safety

  1. @optionalTypeArgs
String restorablePushNamed<T extends Object?>(
  1. String routeName,
  2. {Object? arguments}
)
optionalTypeArgs">@optionalTypeArgs

Push a named route onto the navigator.

Unlike Routes pushed via pushNamed, Routes pushed with this method are restored during state restoration according to the rules outlined in the "State Restoration" section of Navigator.

The route name will be passed to the Navigator.onGenerateRoute callback. The returned route will be pushed into the navigator.

The new route and the previous route (if any) are notified (see Route.didPush and Route.didChangeNext). If the Navigator has any Navigator.observers, they will be notified as well (see NavigatorObserver.didPush).

Ongoing gestures within the current route are canceled when a new route is pushed.

The T type argument is the type of the return value of the route.

To use pushNamed, an Navigator.onGenerateRoute callback must be provided,

The provided arguments are passed to the pushed route via RouteSettings.arguments. Any object that is serializable via the StandardMessageCodec can be passed as arguments. Often, a Map is used to pass key-value pairs.

The arguments may be used in Navigator.onGenerateRoute or Navigator.onUnknownRoute to construct the route.

The method returns an opaque ID for the pushed route that can be used by the RestorableRouteFuture to gain access to the actual Route object added to the navigator and its return value. You can ignore the return value of this method, if you do not care about the route object or the route's return value.

link
Typical usage is as follows: 
void _openDetails() {
  navigator.restorablePushNamed('/nyc/1776');
}

Implementation

@optionalTypeArgs
String restorablePushNamed<T extends Object?>(
  String routeName, {
  Object? arguments,
}) {
  assert(routeName != null);
  assert(debugIsSerializableForRestoration(arguments), 'The arguments object must be serializable via the StandardMessageCodec.');
  final _RouteEntry entry = _RestorationInformation.named(
    name: routeName,
    arguments: arguments,
    restorationScopeId: _nextPagelessRestorationScopeId,
  ).toRouteEntry(this, initialState: _RouteLifecycle.push);
  _pushEntry(entry);
  return entry.restorationId!;
}