unexpectedly found nil while unwrapping an Optional value keyboardWillShow

Question

I have this code below which runs when the keyboardWillShowNotification is called:

func keyboardWillShow(_ notification: Notification) {
    //ERROR IN THE L         


        

Answer 1

From the docs:

let UIKeyboardFrameEndUserInfoKey: String 

Description

The key for an NSValue object containing a CGRect that identifies the end frame of the keyboard in screen coordinates

Your second key:

let UIKeyboardAnimationDurationUserInfoKey: String

Description The key for an NSNumber object containing a double that identifies the duration of the animation in seconds.

So you need to cast the first one to NSValue and the second one to NSNumber:

func keyboardWillShow(_ notification: Notification) {
    print("keyboardWillShow")
    guard let userInfo = notification.userInfo else { return }
    keyboard = (userInfo[UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
    animaton = (userInfo[UIKeyboardAnimationDurationUserInfoKey] as! NSNumber).doubleValue
    // your code
}