Find the first Responder

gistfile1.txt

import UIKit

private weak var currentFirstResponder: AnyObject?

extension UIResponder {
    @objc func findFirstResponder() -> AnyObject? {
        currentFirstResponder = nil
        UIApplication.shared.sendAction(#selector(findFirstResponder(_:)), to: nil, from: self, for: nil)
        return currentFirstResponder
    }
    
    @objc static func findFirstResponder() -> AnyObject? {
        currentFirstResponder = nil
        UIApplication.shared.sendAction(#selector(findFirstResponder(_:)), to: nil, from: nil, for: nil)
        return currentFirstResponder
    }
    
    @objc fileprivate func findFirstResponder(_ sender: AnyObject) {
        currentFirstResponder = self
    }
}