flutter: animate transition to named route

user_497600 0
Viewed 22855

When I use Navigator.pushNamed(context, "/someRoute");, there is a minimal animation which slides in the new route from the bottom of the screen (on Android, might look different on iOS).

How can I add a custom animation to this transition?

I found this article, which has some very neat sample code for unnamed routes. They implement their own class which inherits from PageRouteBuilder and can be used like this: Navigator.push(context, SlideRightRoute(page: Screen2())). But a PageRouteBuilder is not a Widget and can't be registered as a route in MaterialApp. So I don't see how to apply this to named routes.

flutter-animation flutter
3 Answers

You need to use onGenerateRoute in your MaterialApp widget.

onGenerateRoute: (settings) {
  if (settings.name == "/someRoute") {
    return PageRouteBuilder(
      settings: settings, // Pass this to make popUntil(), pushNamedAndRemoveUntil(), works
      pageBuilder: (_, __, ___) => SomePage(),
      transitionsBuilder: (_, a, __, c) => FadeTransition(opacity: a, child: c)
    );
  }
  // Unknown route
  return MaterialPageRoute(builder: (_) => UnknownPage());
},
user_66186220

Using animated routes is possible without onGenerateRoute!

If you are using MaterialApp's routes map for defining your named routes, here is how you could define a named route (whose name will not be null).

Just create your route by extending PageRouteBuilder:

import 'package:flutter/material.dart';

class FadeInRoute extends PageRouteBuilder {
  final Widget page;

  FadeInRoute({this.page, String routeName})
      : super(
          settings: RouteSettings(name: routeName),            // set name here
          pageBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
          ) =>
              page,
          transitionsBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
            Widget child,
          ) =>
              FadeTransition(
            opacity: animation,
            child: child,
          ),
          transitionDuration: Duration(milliseconds: 500),
        );
}

and then when you are navigating, just do:

Navigator.push( // or pushReplacement, if you need that
  context,
  FadeInRoute(
    routeName: RouteNames.home,
    page: MyHomeScreen(),
  ),
);
user_21011170

I found an easy solution (inspired from this code)

First, you need to set a static GlobalKey for MaterialApp and export it

static GlobalKey mtAppKey = GlobalKey();

Widget build(BuildContext context) {
  return MaterialApp(
    key: MyApp.mtAppKey,
    ...

Also, you need to a custom PageRouteBuilder to handle it

Null-safety disabled

class CustomNamedPageTransition extends PageRouteBuilder {
  CustomNamedPageTransition(
    GlobalKey materialAppKey,
    String routeName, {
    Object arguments,
  }) : super(
          settings: RouteSettings(
            arguments: arguments,
            name: routeName,
          ),
          pageBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
          ) {
            assert(materialAppKey.currentWidget != null);
            assert(materialAppKey.currentWidget is MaterialApp);
            var mtapp = materialAppKey.currentWidget as MaterialApp;
            var routes = mtapp.routes;
            assert(routes.containsKey(routeName));
            return routes[routeName](context);
          },
          transitionsBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
            Widget child,
          ) =>
              FadeTransition(
            opacity: animation,
            child: child,
          ),
          transitionDuration: Duration(seconds: 1),
        );
}

Null-safety enabled

class CustomNamedPageTransition extends PageRouteBuilder {
  CustomNamedPageTransition(
    GlobalKey materialAppKey,
    String routeName, {
    Object? arguments,
  }) : super(
          settings: RouteSettings(
            arguments: arguments,
            name: routeName,
          ),
          pageBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
          ) {
            assert(materialAppKey.currentWidget != null);
            assert(materialAppKey.currentWidget is MaterialApp);
            var mtapp = materialAppKey.currentWidget as MaterialApp;
            var routes = mtapp.routes;
            assert(routes!.containsKey(routeName));
            return routes![routeName]!(context);
          },
          transitionsBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
            Widget child,
          ) =>
              FadeTransition(
            opacity: animation,
            child: child,
          ),
          transitionDuration: Duration(seconds: 1),
        );
}

Then, you can open your named route with

Navigator.push(
  context,
  CustomNamedPageTransition(
    MyApp.mtAppKey,
    MyRoute.routeName,
  ),
);

or

Navigator.pushReplacement(
  context,
  CustomNamedPageTransition(
    MyApp.mtAppKey,
    MyRoute.routeName,
  ),
);
user_162901100
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