swift - 从选择 UITextField 按下到另一个 UITextField 的转换是否会导致 UIView 在 Swift 中重新加载？

Question

应用程序加载后，我会看到以下 View :

一旦我单击“全名”文本字段，键盘就会显示并稍微移动元素，以允许注册按钮保持显示。

当我移至第二个文本字段时出现问题。它导致 View 完全重新加载并将 View 中的所有元素放置到其原始位置，这使得键盘隐藏最低元素。如下图所示

我已经搜索并检查了问题是否来自这样的事实:当我发生此问题时，键盘加载 keyboardwillshow() 和 keyboardwillhide 根本不会被调用已验证。

从选择 UITextField 按下到另一个 UITextField 的转换是否会导致 UIView 重新加载 Xcode？请注意，UIText 字段位于

import UIKit
import SendBirdSDK

class LoginController: UIViewController {

    var keyboardShowing = false

    let inputsContainerView: UIView = {
        let view = UIView()
        view.backgroundColor = UIColor.white
        view.translatesAutoresizingMaskIntoConstraints = false
        view.layer.cornerRadius = 5
        view.layer.masksToBounds = true

        return view
    }()

    lazy var loginRegisterButton: UIButton = {
        let button = UIButton(type: .system)
        button.backgroundColor = UIColor(r: 88, g: 101, b: 161)
        button.setTitle("Register", for: .normal)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.setTitleColor(UIColor.white, for: .normal)
        button.titleLabel?.font = UIFont.boldSystemFont(ofSize: 16)

        button.addTarget(self, action: #selector(handleLoginRegister), for: .touchUpInside)
        return button
    }()

    func handleLoginRegister() {
        if loginRegisterSegmentedControl.selectedSegmentIndex == 0 {
            handleLogin()
        } else {
            handleRegister()
        }
    }


    func handleLogin(){

        guard let userid = fullNameTextField.text, (passwordTextField.text != nil) else {
            print ("Form is not valid")
            return
        }



        SBDMain.connect(withUserId: userid, completionHandler: { (user, error) in
            if error != nil {
                print (error)
                return
            }

            //successfully loggedin user

            self.dismiss(animated: true, completion: nil)


        })
    }



    let nameTextField: UITextField = {
        let tf = UITextField()
        tf.placeholder = "Full Name"
        tf.translatesAutoresizingMaskIntoConstraints = false
        return tf
    }()

    let nameSeperatorView: UIView = {
        let view = UIView()
        view.backgroundColor = UIColor(r: 220, g: 220, b: 220)
        view.translatesAutoresizingMaskIntoConstraints = false
        return view

    }()

    let fullNameTextField: UITextField = {
        let tf = UITextField()
        tf.placeholder = "Username"
        tf.translatesAutoresizingMaskIntoConstraints = false
        return tf
    }()

    let fullNameSeperatorView: UIView = {
        let view = UIView()
        view.backgroundColor = UIColor(r: 220, g: 220, b: 220)
        view.translatesAutoresizingMaskIntoConstraints = false
        return view

    }()

    let passwordTextField: UITextField = {
        let tf = UITextField()
        tf.placeholder = "Password"
        tf.translatesAutoresizingMaskIntoConstraints = false
        tf.isSecureTextEntry = true
        return tf
    }()

    lazy var profileImageView: UIImageView = {
        let imageView = UIImageView()
        imageView.image = UIImage(named: "gameofthrones_splash")
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.contentMode = .scaleAspectFill

        imageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(handleSelectProfileImageView)))
        imageView.isUserInteractionEnabled = true

        return imageView
    }()



    lazy var loginRegisterSegmentedControl: UISegmentedControl = {
        let sc = UISegmentedControl(items: ["Login", "Register"])
        sc.translatesAutoresizingMaskIntoConstraints = false
        sc.tintColor = UIColor.white
        sc.selectedSegmentIndex = 1
        sc.addTarget(self, action: #selector(handleLoginRegisterChange), for: .valueChanged)
        return sc
    }()

    func handleLoginRegisterChange() {
        if keyboardShowing == true {
            view.endEditing(true)
        }
        /*else  {
            view.endEditing(false)
        }*/

        let title = loginRegisterSegmentedControl.titleForSegment(at: loginRegisterSegmentedControl.selectedSegmentIndex)
        loginRegisterButton.setTitle(title, for: UIControlState())

        // change height of inputContainerView, but how???
        inputsContainerViewHeightAnchor?.constant = loginRegisterSegmentedControl.selectedSegmentIndex == 0 ? 100 : 150

        // change height of nameTextField
        nameTextFieldHeightAnchor?.isActive = false
        nameTextFieldHeightAnchor = nameTextField.heightAnchor.constraint(equalTo: inputsContainerView.heightAnchor, multiplier: loginRegisterSegmentedControl.selectedSegmentIndex == 0 ? 0 : 1/3)
        nameTextFieldHeightAnchor?.isActive = true
        nameTextField.isHidden = loginRegisterSegmentedControl.selectedSegmentIndex == 0

        fullNameTextFieldHeightAnchor?.isActive = false
        fullNameTextFieldHeightAnchor = fullNameTextField.heightAnchor.constraint(equalTo: inputsContainerView.heightAnchor, multiplier: loginRegisterSegmentedControl.selectedSegmentIndex == 0 ? 1/2 : 1/3)
        fullNameTextFieldHeightAnchor?.isActive = true

        passwordTextFieldHeightAnchor?.isActive = false
        passwordTextFieldHeightAnchor = passwordTextField.heightAnchor.constraint(equalTo: inputsContainerView.heightAnchor, multiplier: loginRegisterSegmentedControl.selectedSegmentIndex == 0 ? 1/2 : 1/3)
        passwordTextFieldHeightAnchor?.isActive = true

    }



    override func viewDidLoad() {
        super.viewDidLoad()



        view.backgroundColor = UIColor(r: 61, g: 91, b: 151)

        view.addSubview(inputsContainerView)
        view.addSubview(loginRegisterButton)
        view.addSubview(profileImageView)
        view.addSubview(loginRegisterSegmentedControl)


        setupInputsContainerView()
        setupLoginRegisterButton()
        setupProfileImageView()
        setupLoginRegisterSegmentedControl()

        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)

        //connecting to the application
        SBDMain.initWithApplicationId("1662A8E8-F45F-454B-9E5E-02362342ECC5")



    }

   func keyboardWillShow(notification: NSNotification) {

        print ("keyboardwillshow was called")

        if self.keyboardShowing {
            return
        }



            if self.keyboardShowing == false {
                self.inputsContainerView.frame.origin.y -= 58
                self.loginRegisterButton.frame.origin.y -= 58
                self.loginRegisterSegmentedControl.frame.origin.y -= 58
                self.profileImageView.frame.origin.y -= 58

            }
            self.keyboardShowing = true

    }

    func keyboardWillHide(notification: NSNotification) {

         print ("keyboardwillhide was called")

        if !self.keyboardShowing {
            return
        }


            if self.keyboardShowing == true {
                self.inputsContainerView.frame.origin.y += 58
                self.loginRegisterButton.frame.origin.y += 58
                self.loginRegisterSegmentedControl.frame.origin.y += 58
                self.profileImageView.frame.origin.y += 58
            }
            self.keyboardShowing = false

    }

    func setupLoginRegisterSegmentedControl() {
        //need x, y, width, height constraints
        loginRegisterSegmentedControl.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        loginRegisterSegmentedControl.bottomAnchor.constraint(equalTo: inputsContainerView.topAnchor, constant: -12).isActive = true
        loginRegisterSegmentedControl.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor, multiplier: 1).isActive = true
        loginRegisterSegmentedControl.heightAnchor.constraint(equalToConstant: 36).isActive = true
    }

    func setupProfileImageView(){

        //need x, y, width, height constraints
        profileImageView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        profileImageView.bottomAnchor.constraint(equalTo: loginRegisterSegmentedControl.topAnchor, constant: -12).isActive = true
        profileImageView.widthAnchor.constraint(equalToConstant: 150).isActive = true
        profileImageView.heightAnchor.constraint(equalToConstant: 150).isActive = true


    }

    var inputsContainerViewHeightAnchor: NSLayoutConstraint?
    var nameTextFieldHeightAnchor: NSLayoutConstraint?
    var fullNameTextFieldHeightAnchor: NSLayoutConstraint?
    var passwordTextFieldHeightAnchor: NSLayoutConstraint?

    func setupInputsContainerView(){
        //need x, y, width, height constraints
        inputsContainerView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        inputsContainerView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        print(self.inputsContainerView.frame.origin.y)
        inputsContainerView.widthAnchor.constraint(equalTo: view.widthAnchor, constant: -24).isActive = true
        inputsContainerViewHeightAnchor = inputsContainerView.heightAnchor.constraint(equalToConstant: 150)
        inputsContainerViewHeightAnchor?.isActive = true

        inputsContainerView.addSubview(nameTextField)
        inputsContainerView.addSubview(nameSeperatorView)
        inputsContainerView.addSubview(fullNameTextField)
        inputsContainerView.addSubview(fullNameSeperatorView)
        inputsContainerView.addSubview(passwordTextField)

        //need x, y, width, height constraints
        nameTextField.leftAnchor.constraint(equalTo: inputsContainerView.leftAnchor, constant: 12).isActive = true
        nameTextField.topAnchor.constraint(equalTo: inputsContainerView.topAnchor).isActive = true

        nameTextField.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor).isActive = true
        nameTextFieldHeightAnchor = nameTextField.heightAnchor.constraint(equalTo: inputsContainerView.heightAnchor, multiplier: 1/3)
        nameTextFieldHeightAnchor?.isActive = true

        //need x, y, width, height constraints
        nameSeperatorView.leftAnchor.constraint(equalTo: inputsContainerView.leftAnchor).isActive = true
        nameSeperatorView.topAnchor.constraint(equalTo: nameTextField.bottomAnchor).isActive = true
        nameSeperatorView.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor).isActive = true
        nameSeperatorView.heightAnchor.constraint(equalToConstant: 1).isActive = true

        //need x, y, width, height constraints
        fullNameTextField.leftAnchor.constraint(equalTo: inputsContainerView.leftAnchor, constant: 12).isActive = true
        fullNameTextField.topAnchor.constraint(equalTo: nameTextField.bottomAnchor).isActive = true

        fullNameTextField.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor).isActive = true

        fullNameTextFieldHeightAnchor = fullNameTextField.heightAnchor.constraint(equalTo: inputsContainerView.heightAnchor, multiplier: 1/3)

        fullNameTextFieldHeightAnchor?.isActive = true

        //need x, y, width, height constraints
        fullNameSeperatorView.leftAnchor.constraint(equalTo: inputsContainerView.leftAnchor).isActive = true
        fullNameSeperatorView.topAnchor.constraint(equalTo: fullNameTextField.bottomAnchor).isActive = true
        fullNameSeperatorView.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor).isActive = true
        fullNameSeperatorView.heightAnchor.constraint(equalToConstant: 1).isActive = true

        //need x, y, width, height constraints
        passwordTextField.leftAnchor.constraint(equalTo: inputsContainerView.leftAnchor, constant: 12).isActive = true
        passwordTextField.topAnchor.constraint(equalTo: fullNameTextField.bottomAnchor).isActive = true

        passwordTextField.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor).isActive = true
        passwordTextFieldHeightAnchor = passwordTextField.heightAnchor.constraint(equalTo: inputsContainerView.heightAnchor, multiplier: 1/3)
        passwordTextFieldHeightAnchor?.isActive = true
    }

    func setupLoginRegisterButton(){

        //need x, y, width, height constraints
        loginRegisterButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        loginRegisterButton.topAnchor.constraint(equalTo: inputsContainerView.bottomAnchor, constant: 12).isActive = true
        loginRegisterButton.widthAnchor.constraint(equalTo: inputsContainerView.widthAnchor).isActive = true
        loginRegisterButton.heightAnchor.constraint(equalToConstant: 50).isActive = true

    }

    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }



}

extension UIColor {

    convenience init(r: CGFloat, g: CGFloat, b: CGFloat ) {
        self.init(red: r/255, green: g/255, blue: b/255, alpha: 1)
    }

}

Answer 1

不要移动 UIView 的元素，而是像这样移动整个 View 框架:

func keyboardWillShow(notification: NSNotification) {

    print ("keyboardwillshow was called")

    if self.keyboardShowing {
        return
    }



        if self.keyboardShowing == false {
            /*self.inputsContainerView.frame.origin.y -= 58
            self.loginRegisterButton.frame.origin.y -= 58
            self.loginRegisterSegmentedControl.frame.origin.y -= 58
            self.profileImageView.frame.origin.y -= 58*/

            self.view.frame.origin.y -= 58

        }
        self.keyboardShowing = true

}

func keyboardWillHide(notification: NSNotification) {

     print ("keyboardwillhide was called")

    if !self.keyboardShowing {
        return
    }


        if self.keyboardShowing == true {
           /* self.inputsContainerView.frame.origin.y += 58
            self.loginRegisterButton.frame.origin.y += 58
            self.loginRegisterSegmentedControl.frame.origin.y += 58
            self.profileImageView.frame.origin.y += 58*/

            self.view.frame.origin.y += 58
        }
        self.keyboardShowing = false

}