iOS swift4，单击多个UITextField，键盘显示，向上移动的UIButton不知道为什么向下移动

Question

多个UITextField，软键盘显示和UIButton在单击一个UITextField时向上移动。

单击空白区域时，键盘关闭。

现在显示键盘，单击另一个UITextField，向下移动UIButton，此时键盘仍显示，我不想让UIButton下移。

为什么键盘显示时UIButton下移？

Gif屏幕截图

• click1：键盘显示
• click2：键盘隐藏
• click3：键盘显示
• click4：键盘显示，但我不希望UIButton下移。
• 继续单击click3和click4，UIButton仍在下面。
• 双击UITextField，UIButton将从新版本上移

下面是代码

class LoginPasswordViewController: UIViewController, UITextFieldDelegate {
    @IBOutlet weak var phoneInput: UITextField! // this is the first UITextField
    @IBOutlet weak var passwordInput: UITextField! // this is the second UITextField
    @IBOutlet weak var btnOK: UIButton! // this is the UIButton, it move up when Soft keyboard show.
    fileprivate var btnOKOriginY: CGFloat!
    fileprivate var isShow: Bool?

    override func viewDidLoad() {
        super.viewDidLoad()
        // observer keyboard show
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(keyboardWillShow),
            name: NSNotification.Name.UIKeyboardWillShow,
            object: nil)

        // observer keyboard hide
        NotificationCenter.default.addObserver(
            self,
            selector: #selector(keyboardWillHide),
            name: NSNotification.Name.UIKeyboardWillHide,
            object: nil)
    }

    @objc func keyboardWillHide(_ notification: Notification) {
        btnOK.frame.origin.y = btnOKOriginY
        isShow = false
    }

    @objc func keyboardWillShow(_ notification: Notification) {

        if let keyboardFrame: NSValue = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue {
            print("btnOK.frame.origin.y = ", btnOK.frame.origin.y)

            if  isShow ?? false && btnOK.frame.origin.y != btnOKOriginY{
                return
            }
            isShow = true
            if btnOKOriginY == nil {
                btnOKOriginY = btnOK.frame.origin.y
            }

            let keyboardRectangle = keyboardFrame.cgRectValue
            let keyboardHeight = keyboardRectangle.height
            btnOK.frame.origin.y = btnOKOriginY - keyboardHeight
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        closeSoftKey()
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        closeSoftKey()
        return true
    }

    func closeSoftKey() {
        phoneInput.resignFirstResponder()
        passwordInput.resignFirstResponder()
    }

}

Answer 1

UIButton通过swift代码进行初始化，问题不再存在...

下面是代码，其他保持不变

var btnOK: UIButton!

func initUIButton() {

    btnOK = UIButton(frame: CGRect(x: self.view.frame.width - 55 - 16,
                                   y: self.view.frame.height - 55 - 32,
                                   width: 55,
                                   height: 55))
    btnOK.setImage( imageLiteral(resourceName: "ic_next"), for: .normal)
    self.view.addSubview(btnOK)
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    initUIButton()
}