[Swift 4] 키보드 내리기 (hideKeyboard) - dismissKeyboard

TextField 이외에 부분에 Tap하면, 키보드 내리기.

ViewContoller.swift (Swift 4)

class ViewController: UIViewController {
	override func viewDidLoad() {
		super.viewDidLoad()

		self.hideKeyboard() // <- 추가
	}
}

// extension 추가
extension UIViewController {
	func hideKeyboard() {
		let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, 
			action: #selector(UIViewController.dismissKeyboard))
		view.addGestureRecognizer(tap)
	}
	@objc func dismissKeyboard() {
		view.endEditing(true)
	}
}