Let‘s say you set widget height to 200, but to different screen, there might not be enough space for the widget to display, in this case, you can use Flexible widget:
Flexible( child: Hero( tag: ‘flash‘, child: Container( height: 200.0, child: Image.asset(‘images/logo.png‘), ), ), ),
It will display enough space for Widget which it wraps. Save space for other Widgets.
[Flutter] Flexible the Widget height to available space
原文：https://www.cnblogs.com/Answer1215/p/11870381.html