position a view in storyboard at 1/3 of screen size

问题

I'm trying to position a view in storyboard to always have it top edge at 1/3 of screen size. I have currently set a constraint to Top Layout Guide, but the constraint's constant is...well it is constant no matter which screen size it is used in, but I want it to be 1/3 of screen size. Can this be done entirely in storyboard? Thanks for answers

Screenshot of current state:

回答1:

Create a constraint between the view's top edge and the superview's bottom edge. Set the constraint's constant to zero, and set its multiplier to 1:3. Like this:

回答2:

You can setup it against center or bottom. Here is an example constraints related to center: (1/3 from top = 1.66 from center)

回答3:

You can add empty (clear color) UIView, pin it to the top, and set it's height to be equal to 1/3 of the superview. Then you can pin the top of your yellow view to the bottom of your empty UIView.

回答4:

For anyone trying to make this work programatically I was not able to handle that by 'anchors' style but old NSLayoutConstraint initializer worked:

let constraint = NSLayoutConstraint(item: floatingBtn,
                                    attribute: .centerY,
                                    relatedBy: .equal,
                                    toItem: view,
                                    attribute: .bottom,
                                    multiplier: 1/3,
                                    constant: 0)
constraint.isActive = true

Credits to accepted answer.

来源：https://stackoverflow.com/questions/32100248/position-a-view-in-storyboard-at-1-3-of-screen-size