pushAndRemoveUntil<T extends Object> method

  1. @optionalTypeArgs
Future<T> pushAndRemoveUntil <T extends Object>(Route<T> newRoute, RoutePredicate predicate)
@optionalTypeArgs

Push the given route onto the navigator, and then remove all the previous routes until the predicate returns true.

The predicate may be applied to the same route more than once if Route.willHandlePopInternally is true.

To remove routes until a route with a certain name, use the RoutePredicate returned from ModalRoute.withName.

To remove all the routes below the pushed route, use a RoutePredicate that always returns false (e.g. (Route<dynamic> route) => false).

The removed routes are removed without being completed, so this method does not take a return value argument.

The new route and the route below the bottommost removed route (which becomes the route below the new route) are notified (see Route.didPush and Route.didChangeNext). If the Navigator has any Navigator.observers, they will be notified as well (see NavigatorObservers.didPush and NavigatorObservers.didRemove). The removed routes are disposed, without being notified, once the new route has finished animating. The futures that had been returned from pushing those routes will not complete.

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

Returns a Future that completes to the result value passed to pop when the pushed route is popped off the navigator.

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

Typical usage is as follows: 
void _resetAndOpenPage() {
  navigator.pushAndRemoveUntil(
    MaterialPageRoute(builder: (BuildContext context) => MyHomePage()),
    ModalRoute.withName('/'),
  );
}

Implementation 

@optionalTypeArgs
Future<T> pushAndRemoveUntil<T extends Object>(Route<T> newRoute, RoutePredicate predicate) {
  assert(!_debugLocked);
  assert(() { _debugLocked = true; return true; }());
  final List<Route<dynamic>> removedRoutes = <Route<dynamic>>[];
  while (_history.isNotEmpty && !predicate(_history.last)) {
    final Route<dynamic> removedRoute = _history.removeLast();
    assert(removedRoute != null && removedRoute._navigator == this);
    assert(removedRoute.overlayEntries.isNotEmpty);
    removedRoutes.add(removedRoute);
  }
  assert(newRoute._navigator == null);
  assert(newRoute.overlayEntries.isEmpty);
  final Route<dynamic> oldRoute = _history.isNotEmpty ? _history.last : null;
  newRoute._navigator = this;
  newRoute.install(_currentOverlayEntry);
  _history.add(newRoute);
  newRoute.didPush().whenCompleteOrCancel(() {
    if (mounted) {
      for (Route<dynamic> route in removedRoutes)
        route.dispose();
    }
  });
  newRoute.didChangeNext(null);
  if (oldRoute != null)
    oldRoute.didChangeNext(newRoute);
  for (NavigatorObserver observer in widget.observers) {
    observer.didPush(newRoute, oldRoute);
    for (Route<dynamic> removedRoute in removedRoutes)
      observer.didRemove(removedRoute, oldRoute);
  }
  assert(() { _debugLocked = false; return true; }());
  _afterNavigation();
  return newRoute.popped;
}