height property
高。如果只有 height,而没有 width,将获得一个垂直方向的虚线 如果同时有 width 和 height,将获得一个虚线边框。
height. If there is only height and no width, you will get a dotted line in the vertical direction If there are both width and height, you will get a dotted border.
Implementation
final double? height;