Flutter 容器布局行为

Question

当我阅读 Container document 的容器布局行为时:

If the widget has no child, no height, no width, no constraints, and the parent provides unbounded constraints, then Container tries to size as small as possible.

所以我写了一些像下面这样的代码，我认为第二个容器应该尽可能小，但它填满了应用程序的内容区域(整个屏幕)，为什么？

class ContainerWithScaffold extends StatelessWidget {
@override
Widget build(BuildContext context) {
return new MaterialApp(
  title: 'Container with scaffold',
  home: Scaffold(
    body: Container(
      color: Colors.blue,
      height: double.infinity,// provides unbounded height constraints for the child container
      width: double.infinity,// provides unbounded width constraints for the child container
      child: new Container(
        color: Colors.white,
      ),
    ),
  ),
);
}
}

Answer 1

您设置了高度和宽度，尝试使用 UnconstrainedBox

      Container(
                color: Colors.blue,
                height: double
                    .infinity, // provides unbounded height constraints for the child container
                width: double
                    .infinity, // provides unbounded width constraints for the child container
                child: UnconstrainedBox(
                  child: new Container(
                    color: Colors.red,
                  ),
                ),
              ),

更多信息:https://docs.flutter.io/flutter/widgets/UnconstrainedBox-class.html