当视图已经显示时如何防止键盘向上移动视图

Question

I got the keyboard to move up when I click a textfield but as soon as I click another textfield It move the view up even more. Thank you for your help.

func keyboardStates() {
        NotificationCenter.default.addObserver(self, selector: 
#selector(keyboardWillChange(notification:)), name: 
UIResponder.keyboardWillShowNotification, object: nil)
        NotificationCenter.default.addObserver(self, selector: 
#selector(keyboardWillChange(notification:)), name: 
UIResponder.keyboardWillHideNotification, object: nil)
}

deinit {
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
    NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
}


@objc func keyboardWillChange(notification: Notification){

    guard let keyboardRect = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {

        return
    }

    if notification.name == UIResponder.keyboardWillShowNotification {
        view.frame.origin.y = -keyboardRect.height/3
    } else {
        view.frame.origin.y = 0
    }
}

Answer 1

Try the below method,

@objc
    func keyboardWillChange(_ notification: NSNotification) {
        guard let duration = notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as? Double else { return }
        guard let curve = notification.userInfo?[UIResponder.keyboardAnimationCurveUserInfoKey] as? UInt else { return }
        guard let startingFrame = (notification.userInfo?[UIResponder.keyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue else { return }
        guard let endingFrame = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else { return }
        let deltaY = endingFrame.origin.y - startingFrame.origin.y
        UIView.animateKeyframes(withDuration: duration, delay: 0.0, options: UIView.KeyframeAnimationOptions(rawValue: curve), animations: {
            self.frame.origin.y += deltaY
        }, completion: nil)
    }

Answer 2

var keyboardHasShown = false 

@objc func keyboardWillChange(notification: Notification){

guard let keyboardRect = (notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else {

    return
}

if notification.name == UIResponder.keyboardWillShowNotification {
    if keyboardHasShown == false {
      view.frame.origin.y = -keyboardRect.height/3

   }
    keyboardHasShown = true
} else {
    view.frame.origin.y = 0
    keyboardHasShown = false
}
}

Answer 3

Well doing it per view controller basis will be difficult and time consuming, i would recommend to use this fantastic library for such tasks, it supports, scroll view, table view and collection view.

https://github.com/hackiftekhar/IQKeyboardManager

Give it a try and i assure you will like it too.

Regards, Harish