AutoLayout圆形UIButton-等效的垂直和水平大小

Question

How do you make a UIButton's vertical distance equivalent to a UIButton's horizontal distance in AutoLayout.

Using Visual Format Language, I can currently make all UIButtons have the equivalent height or width, but I don't know how to specify those to be the same.

I also do not want this distance to be predefined which I know is possible through setting metrics.

Answer 1

You can't use vfl for this.

You have to use the method...

AddConstraintForItem:attribute:relation:toItem:attribute:multiplier:constant.

Or something like that anyway.

Both items can be the same and the two attributes set one to width and one to height.

Answer 2

Figured out a solution to this. You can't use Visual Format Language, but rather need to use NSLayoutConstraint constraintWithItem

NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:forwardButton attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:forwardButton attribute:NSLayoutAttributeWidth multiplier:1.0 constant:0];
[self.view addConstraint:constraint];