hero-widget.dart

// Hero in screen current screen
child: new Hero(
          createRectTween: createRectTween,
          tag: planet.name,
          child: new RadialExpansion(
            maxRadius: kMaxRadius,
            child: new Photo(
              photo: planet.imagePath,
              onTap: () {
                Navigator.of(context).push(new PageRouteBuilder(
                  pageBuilder:
                      (BuildContext context, Animation<double> animation, Animation<double> secondaryAnimation) {
                    return new AnimatedBuilder(
                        animation: animation,
                        builder: (context, child) => new HeroAnimation2(planet, animation, durationSlowMode));
                  },
                ));
              },
            ),
          ),
        ),

// Hero in next screen
child: new Hero(
  createRectTween: createRectTween,
  tag: planet.name,
  child: new RadialExpansion(
    maxRadius: kMaxRadius,
    child: new Photo(
      photo: planet.imagePath,
      onTap: () {
        Navigator.of(context).pop();
      },
    ),
),
),