An UIView extension with a method to return the frame of the first responder.

UIViewFirstResponder.swift

extension UIView {
    
    func frameOfFirstResponder() -> CGRect? {
        if self.isFirstResponder {
            return self.frame
        }
        for view in self.subviews {
            if let frame = view.frameOfFirstResponder() {
                return frame
            }
        }
        return nil
    }
}