UIResponder+FirstResponder.swift

import UIKit

extension UIResponder {
    
    private weak static var _currentFirstResponder: UIResponder?
    
    static var currentFirstResponder: UIResponder? {
        get {
            _currentFirstResponder = nil
            UIApplication.sharedApplication().sendAction(#selector(findFirstResponder), to: nil, from: nil, forEvent: nil)
            return _currentFirstResponder
        }
        set {
            _currentFirstResponder = newValue
        }
    }
    
    @objc private func findFirstResponder() {
        UIResponder.currentFirstResponder = self
    }
}