Transparent PageRoute in Flutter for displaying a (semi-) transparent page

import 'package:flutter/widgets.dart';

class TransparentRoute extends PageRoute<void> {
  TransparentRoute({
    @required this.builder,
    RouteSettings settings,
  })  : assert(builder != null),
        super(settings: settings, fullscreenDialog: false);

  final WidgetBuilder builder;

  @override
  bool get opaque => false;

  @override
  Color get barrierColor => null;

  @override
  String get barrierLabel => null;

  @override
  bool get maintainState => true;

  @override
  Duration get transitionDuration => Duration(milliseconds: 350);

  @override
  Widget buildPage(BuildContext context, Animation<double> animation,
      Animation<double> secondaryAnimation) {
    final result = builder(context);
    return FadeTransition(
      opacity: Tween<double>(begin: 0, end: 1).animate(animation),
      child: Semantics(
        scopesRoute: true,
        explicitChildNodes: true,
        child: result,
      ),
    );
  }
}

　　

Keep in mind that this would also create a custom transition animation and behave differently than the more complex MaterialPageRoute (e.g. the swipe-back gesture would not work with the current implementation on iOS).

You could use it like this:

Navigator.of(context).push(
    TransparentRoute(builder: (BuildContext context) => YourSecondPage())
);

　　

For more info on the PageRoute and the different implementers, head over to https://docs.flutter.io/flutter/widgets/PageRoute-class.html