Autolayout: origin and size should change according to width and height factor

Question

Here is a scenario what I needed.

I have put a UIButton on IB (size iPhone4 inch) whose initial frame on IB is x:100,y:100,w:100,h:100. I want the o

Answer 1

For height and width, create an "aspect ratio" constraint in Interface Builder linking the button to the superview. There is no property for aspect ratio; it will use the values at the time it was created to set the multiplier (If iPhone <= 5 width and linking superview to button widths, it will be 320:100) . Add a second constraint for aspect ratio linking the button height to superview height (if you didn't want the height to stretch with the iPhone 5, you could link the buttons aspect ratio to itself.).

For origin, I don't think there's a way to link origin of views and size of views. To set origin to an arbitrary height or width based on size of the screen, you do need to create a spacer view. Inelegant, but necessary. Add the view and set it hidden (and name it in the object outline to the left, which when working with autolayout in IB you probably want to do with everything to make the constraints readable, but definitely here so you can find it again easily). Set create constraints to zero linking it to the button and the top layout guide, and zero to the superview.leading and button leading.

To adjust the spacing you can create aspect ratio constraints, to both the superview width and to the superview height, or just set it equal to the button width and height.