iOS自动布局：将一个按钮的边缘与另一个按钮的中心对齐？

Question

So I have two UIButtons that I'd like to align, but not specifically the edges. I would like to align the (left) edge of one button to the (horizontal) center of another button. So I want it to look like this:

How would I do this AutoLayout in Interface Builder and/or programatically? I hope this isn't too much of a beginner question, but iOS AutoLayout can be so confusing at times...

Answer 1

In IB, create any horizontal constraint between the two buttons. For example, align their centers. Then, select the new constraint object and the Size inspector. There, you can change which attributes are aligned. Select the leading edge of the top button. Now the CenterX of the bottom button is aligned to the leading edge of the top button.