How to keep a round imageView round using auto layout?

Question

How do I turn a rectangular image view into a circular image view that can hold shape in auto layout without setting width and height restraints? Thereby allowing the imageV

Answer 1

Unfortunately you cannot do this using cornerRadius and autolayout — the CGLayer is not affected by autolayout, so any change in the size of the view will not change the radius which has been set once causing, as you have noticed, the circle to lose its shape.

You can create a custom subclass of UIImageView and override layoutSubviews in order to set the cornerRadius each time the bounds of the imageview change.

EDIT

An example might look something like this:

class Foo: UIImageView {
    override func layoutSubviews() {
        super.layoutSubviews()

        let radius: CGFloat = self.bounds.size.width / 2.0

        self.layer.cornerRadius = radius
    }
}

And obviously you would have to constrain the Foobar instance's width to be the same as the height (to maintain a circle). You would probably also want to set the Foobar instance's contentMode to UIViewContentMode.ScaleAspectFill so that it knows how to draw the image (this means that the image is likely to be cropped).