当我们使用不同大小和类型的屏幕时，如何在iOS中设置UI控件的宽度和高度限制？

Question

I am learning Auto-layout in iOS, how setting margin or setting width and height of control will scale according to different size of iPhone and iPad sizes.

For example, if I set image of 200 by 200 in iPhone, will it not look very small as compared to iPad, even iPhone 5S is much smaller than iPhone 6S Plus.

I am missing something important related to Auto-layout?

Answer 1

We always use 'size class' to adapt iPhone and iPad. So if you want to have a image of 200 by 200 in iPhone just setting in wC-hA size, then change size to wR-hR to set 300*300 for iPad.

You maybe not want to set a absolute width to image, the aspect ratio constraint is a good way to set relative width：

It will set the button's width equal to a quarter of superview's width.