Different keyboard heights make weird frames when switching between text view

Question

I have a login screen that gets email and password. the password text field is secured and it results with a different keyboard height. When I switch between the email text field to the password field, without dismissing the keyboard first (clicking on the password while the email keyboard is presented) my frame doesn't recalculate the keyboard height and I get black color in the area of difference between the keyboards. this is the code that handles the keyboard in my View controller, it is obvious that the problem is that the keyboardWillHide/show func's are not being called again and calculate the correct height for the frame if they were not dismissed:

    private func setupKeyboard(){
        let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: "dismissKeyboard")
        view.addGestureRecognizer(tap)

        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillShow), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillHide), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }
    func keyboardWillShow(notification: NSNotification){
        UIView.animate(withDuration: 2.0, animations: {
            self.appLogo.alpha = 0
        })
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            if self.view.frame.origin.y == 0{
                self.view.frame.origin.y -= (keyboardSize.height)
            }
        }
    }
    func keyboardWillHide(notification: NSNotification){
        self.appLogo.alpha = 1
        if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
            if self.view.frame.origin.y != 0{
                self.view.frame.origin.y += (keyboardSize.height)
            }
        }
    }

    func dismissKeyboard() {
        //Causes the view (or one of its embedded text fields) to resign the first responder status.
        appLogo.isHidden = false
        view.endEditing(true)
    }

I am looking for a method that will fix this situation, maybe that when I click on the password field, it will first dissmiss the email field keyboard and then open the password keyboard. Any help appreciated.

In keyboardWillHide why don't you just set the origin back to 0 instead of adding the keyboard height? — paulvs
@paulvs sounds like a nice direction, not sure I understand how to implement it — Eyzuky
ok this actually fixed some weird issues that I had, but still did not entirely fixed the problem. thanks — Eyzuky

paulvs paulvs · Accepted Answer · 2017-05-16T15:34:06

The main problem is that you're using relative offsets (adding and subtracting to the origin of your view), instead of setting absolute values. This, combined with some un-necessary origin checks, causes the gap. Try this:

    func keyboardWillShow(notification: NSNotification){
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        self.view.frame.origin.y = -keyboardSize.height
    }
}
func keyboardWillHide(notification: NSNotification){
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameBeginUserInfoKey] as? NSValue)?.cgRectValue {
        self.view.frame.origin.y = 0
    }
}

Different keyboard heights make weird frames when switching between text view

1 Answers