Смена цвета с анимацией

Можно ли сделать смену цвета нижнего бара с анимацией наподобие как анимация AnimatedSwithcer. Сделал так, но так как в ColorTween нужно указывать начальный и конечный цвет не получается сделать переход.

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage>
    with SingleTickerProviderStateMixin {
  AnimationController animationController;


  _MyHomePageState({this.animationController});

  @override
  void initState() {
    animationController = AnimationController(
        duration: const Duration(milliseconds: 500), vsync: this);
    BlocProvider.of<BottomNavigationBloc>(context)
        .colorTween
        .animate(animationController); 
    super.initState();
  }

  @override
  void dispose() {
    super.dispose();
    animationController.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: PreferredSize(
        preferredSize: Size.fromHeight(50.0),
        child: AppBar(),
      ),
      body: BlocBuilder<BottomNavigationBloc, BottomNavigationState>(
          builder: (context, state) {
        if (state is Page1Loaded) {
         return Page1();
        }
        if (state is Page2Loaded) {
          return Page2();
        }
        if (state is Page3Loaded) {
          return Page3();
        }
        return Container();
      }),
      bottomNavigationBar:
          BlocBuilder<BottomNavigationBloc, BottomNavigationState>(
        builder: (context, state) {
          return AnimatedBuilder(
            animation: animationController,
            builder: (context, child) {
              return BottomNavigationBar(
                backgroundColor: BlocProvider.of<BottomNavigationBloc>(context)
                    .colorTween
                    .animate(animationController)
                    .value,
                onTap: (index) async {
                  BlocProvider.of<BottomNavigationBloc>(context)
                      .add(OnTap(index: index));
                  if (animationController.status == AnimationStatus.completed) {
                    animationController.reset();
                    animationController.forward();
                  } else {
                    animationController.forward();
                  }
                },
                currentIndex:
                    BlocProvider.of<BottomNavigationBloc>(context).currentIndex,
                type: BottomNavigationBarType.fixed,
                items: [],
              );
            },
          );
        },
      ),
    );
  }
}