How to center a subview of UIView

I have a UIView inside a UIViewm and I want the inner UIView to be always centered inside the outer one, without it having to resize the width and height.

I've set the struts and springs so that it's on top/left/right/bottom without setting the resize. But it still doesn't center. Any idea?

You can do this and it will always work:

child.center = [parent convertPoint:parent.center fromView:parent.superview];

And for Swift:

child.center = parent.convert(parent.center, from:parent.superview)

Objective-C

yourSubView.center = CGPointMake(yourView.frame.size.width  / 2, 
                                 yourView.frame.size.height / 2);

Swift

yourSubView.center = CGPoint(x: yourView.frame.size.width  / 2,
                             y: yourView.frame.size.height / 2)