Is there a UIView resize event?

Question

I have a view that has rows and columns of imageviews in it.

If this view is resized, I need to rearrange the imageviews positions.

This view is a subview of

Answer 1

In a UIView subclass, property observers can be used:

override var bounds: CGRect {
    didSet {
        // ...
    }
}

Without subclassing, key-value observation with smart key-paths will do:

var boundsObservation: NSKeyValueObservation?

func beginObservingBounds() {
    boundsObservation = observe(\.bounds) { capturedSelf, _ in
        // ...
    }
}