UIButton与键盘一起移动。 用户按下键时位置重置

Question

I have a function that moves the UIButton that is at the bottom of the screen with the keyboard. The problem is, when the user presses a key (Begins to write in the text field) the button goes back down.

I tried to set addBtn.translatesAutoresizingMaskIntoConstraints = true

This works only if my Xcode has the main.storyboard set as the simulator, otherwise it breaks the constraints. At first I thought it's just a Xcode 9 bug but then I uploaded a bundle on iTunes Connect and asked my girlfriend to download the app through TestFlight and indeed the constraints were messed up when setting the translatesAutoresizingMaskIntoConstraints = true

func bindToKeyboard () {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(_:)), name: NSNotification.Name.UIKeyboardWillChangeFrame , object: nil)
}

@objc func keyboardWillChange(_ notification : NSNotification) {
    let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
    let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
    let startingFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    let endingFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

    let deltaY = endingFrame.origin.y - startingFrame.origin.y

    UIView.animateKeyframes(withDuration: duration, delay: 0.0, options: UIViewKeyframeAnimationOptions(rawValue: curve), animations: {self.frame.origin.y += deltaY
    },completion: nil)
}

Answer 1

OK so after 3 hours of fighting with this bug I disabled the autoresizingmasks and I created an outlet for the bottom constraint .

After every animation I updated that constraint with deltaY

so my code looks like this now

func bindToKeyboard () {
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange(_:)), name: NSNotification.Name.UIKeyboardWillChangeFrame , object: nil)
}

@objc func keyboardWillChange(_ notification : NSNotification) {
    let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
    let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
    let startingFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
    let endingFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue

    let deltaY = endingFrame.origin.y - startingFrame.origin.y

    UIView.animateKeyframes(withDuration: duration, delay: 0.0, options: UIViewKeyframeAnimationOptions(rawValue: curve), animations: {self.frame.origin.y += deltaY
    },completion: nil)


    btc.constant -= deltaY
}

What a pleasant saturday night! I love programming!