Flutter: custom transition (PageRouteBuilder) disables Hero animations

Question

I am currently trying to make a custom transition using PageRouteBuilder . However, when i use it, my Hero animations stop working.

Note: It works with other transitions, even other custom ones.

EnterExitRoute.dart

import 'package:flutter/material.dart';

class EnterExitRoute extends PageRouteBuilder {
  final Widget enterPage;
  final Widget exitPage;
  EnterExitRoute({this.exitPage, this.enterPage})
      : super(
          pageBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
          ) {
            return enterPage;
          } ,
          transitionsBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
            Widget child,
          ) {
              return Stack(
                children: <Widget>[
                  SlideTransition(
                    position: new Tween<Offset>(
                      begin: const Offset(0.0, 0.0),
                      end: const Offset(-1.0, 0.0),
                    ).animate(animation),
                    child: exitPage,
                  ),
                  SlideTransition(
                    position: new Tween<Offset>(
                      begin: const Offset(1.0, 0.0),
                      end: Offset.zero,
                    ).animate(animation),
                    child: enterPage,
                  )
                ],
              );
          }
        );
}

My guess is that Hero animation cannot keep up with SlideTransition .

Any ideas on how to fix this ?

Answer 1

As pskink said, the issue was not using the child ref.

Here is the updated & working code

import 'package:flutter/material.dart';

class EnterExitRoute extends PageRouteBuilder {
  final Widget enterPage;
  final Widget exitPage;
  EnterExitRoute({this.exitPage, this.enterPage})
      : super(
          pageBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
          ) {
            return enterPage;
          } ,
          transitionsBuilder: (
            BuildContext context,
            Animation<double> animation,
            Animation<double> secondaryAnimation,
            Widget child,
          ) {
              var curvedAnimation = CurvedAnimation(
              parent: animation,
              curve: Curves.ease,
              );
              return Stack(
                children: <Widget>[
                  SlideTransition(
                    position: new Tween<Offset>(
                      begin: const Offset(0.0, 0.0),
                      end: const Offset(-1.0, 0.0),
                    ).animate(curvedAnimation),
                    child: exitPage,
                  ),
                  SlideTransition(
                    position: new Tween<Offset>(
                      begin: const Offset(1.0, 0.0),
                      end: Offset.zero,
                    ).animate(curvedAnimation),
                    child: child,
                  )
                ],
              );
          }
        );
}