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键盘将显示不称为iOS 12的通知

ios12 keyboard notifications swift ios

Pranav Wadhwa · 技术社区 · 6 年前

在我的应用程序中,我想要一个通知 UIResponder.keyboardWillShowNotification

@objc func keyboardWillShow(_ notification: Notification) {
    print("keyboard will show 2")
    guard let frameValue: NSValue = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue else {
        return
    }
    let keyboardFrame = frameValue.cgRectValue
    UIView.animate(withDuration: animationTime) {
        self.addViewBottomConstraint.constant = keyboardFrame.size.height
        self.view.layoutIfNeeded()
        print("Bottom contraint height = \(self.addViewBottomConstraint.constant)")
    }
}

@objc func keyboardWillHide(_ notification: Notification) {
    UIView.animate(withDuration: animationTime) {
        self.addViewBottomConstraint.constant = 0
        self.view.layoutIfNeeded()
    }
}

override func viewDidLoad() {
    super.viewDidLoad()

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow(_:)), name: UIResponder.keyboardWillShowNotification, object: nil)

    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide(_:)), name: UIResponder.keyboardWillHideNotification, object: nil)
}

在这里,“keyboard will show 2”不打印,但为具有相同通知的其他视图控制器打印。iOS 12中有什么新的东西导致了这一点吗?否则,有没有一个特别的原因不叫它?谢谢你的帮助。