//ViewController 繼承 KeyboardDelegate
ViewController: UIViewController, KeyboardDelegate {
  override func viewDidLoad() {
  super.viewDidLoad()
  // Do any additional setup after loading the view, typically from a nib.
  // 初始化鍵盤
  let keyboardView = MyKeyboard(frame: CGRect(x: 0, y: 0, width: 0, height: 300))
  // 當鍵盤有按鍵按下後，會通知ViewController
  keyboardView.delegate = self
  // 設定input為自定義鍵盤
  textField.inputView = keyboardView
}

//並實作KeyboardDelegate中的keyWasTapped
//實作delegate
  func keyWasTapped(input: Int) {
    textField.insertText(String(input))
  }
}