为啥文本字段的底线不遵循 Swift 中的约束规则？

Posted 2023-02-23

【中文标题】为啥文本字段的底线不遵循 Swift 中的约束规则？

【英文标题】：Why bottom line for text field does not follow the constraints rule in Swift?为什么文本字段的底线不遵循 Swift 中的约束规则？

【发布时间】：2021-12-31 05:40:54

【问题描述】：

这是我项目中的实用程序文件，我在其中设置了文本字段的底线：

import Foundation
import UIKit

class Utilities 

    static func styleTextField(_ textfield:UITextField) 
    
        let bottomLine = CALayer()
    
        bottomLine.frame = CGRect(x: 0, y: textfield.frame.height - 2, width: textfield.frame.width, height: 2)
    
        bottomLine.backgroundColor = UIColor.init(red: 255/255, green: 77/255, blue: 0/255, alpha: 1).cgColor
    
        textfield.borderStyle = .none
    
        textfield.layer.addSublayer(bottomLine)
    
    
    static func styleFilledButton(_ button:UIButton) 
    
        button.backgroundColor = UIColor.init(red: 255/255, green: 77/255, blue: 0/255, alpha: 1)
        button.layer.cornerRadius = 25.0
        button.tintColor = UIColor.white
    
    static func styleFilledButtonweb(_ button:UIButton) 
  
        button.backgroundColor = UIColor.init(red: 255/255, green: 77/255, blue: 0/255, alpha: 1)
        button.layer.cornerRadius = 5.0
        button.tintColor = UIColor.white
    
    static func styleHollowButton(_ button:UIButton) 
    
        button.layer.borderWidth = 2
        button.layer.borderColor = UIColor.init(red: 255/255, green: 77/255, blue: 0/255, alpha: 1).cgColor
        button.layer.cornerRadius = 25.0
        button.tintColor = UIColor.init(red: 255/255, green: 77/255, blue: 0/255, alpha: 1)
     

这是我使用 styleTextField 函数的视图控制器文件：

import UIKit
import FirebaseAuth
import Firebase



class SignUpViewController: UIViewController, UITextFieldDelegate 


    @IBOutlet weak var firstNameTextField: UITextField! 
        didSet 
            var whitePlaceholderText = NSMutableAttributedString()
            let Name  = "Ad"

            whitePlaceholderText = NSMutableAttributedString(string:Name, attributes: [NSAttributedString.Key.font:UIFont(name: "Helvetica Neue", size: 15)!]) // Font
            whitePlaceholderText.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.white, range:NSRange(location:0,length:Name.count))    // Color
            firstNameTextField.attributedPlaceholder = whitePlaceholderText
        
    
    @IBOutlet weak var lastNameTextField: UITextField! 
        didSet 
            var whitePlaceholderText = NSMutableAttributedString()
            let Name  = "Soyad"

            whitePlaceholderText = NSMutableAttributedString(string:Name, attributes: [NSAttributedString.Key.font:UIFont(name: "Helvetica Neue", size: 15)!]) // Font
            whitePlaceholderText.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.white, range:NSRange(location:0,length:Name.count))    // Color
            lastNameTextField.attributedPlaceholder = whitePlaceholderText
        
    
    @IBOutlet weak var emailTextField: UITextField! 
        didSet 
            var whitePlaceholderText = NSMutableAttributedString()
            let Name  = "Email"

            whitePlaceholderText = NSMutableAttributedString(string:Name, attributes: [NSAttributedString.Key.font:UIFont(name: "Helvetica Neue", size: 15)!]) // Font
            whitePlaceholderText.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.white, range:NSRange(location:0,length:Name.count))    // Color
            emailTextField.attributedPlaceholder = whitePlaceholderText
        
    
    @IBOutlet weak var passwordTextField: UITextField! 
        didSet 
            var whitePlaceholderText = NSMutableAttributedString()
            let Name  = "Şifre"

            whitePlaceholderText = NSMutableAttributedString(string:Name, attributes: [NSAttributedString.Key.font:UIFont(name: "Helvetica Neue", size: 15)!]) // Font
            whitePlaceholderText.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.white, range:NSRange(location:0,length:Name.count))    // Color
            passwordTextField.attributedPlaceholder = whitePlaceholderText
        
    
    @IBOutlet weak var passworddogrulaTextField: UITextField! 
        didSet 
            var whitePlaceholderText = NSMutableAttributedString()
            let Name  = "Şifreyi Doğrula"

            whitePlaceholderText = NSMutableAttributedString(string:Name, attributes: [NSAttributedString.Key.font:UIFont(name: "Helvetica Neue", size: 15)!]) // Font
            whitePlaceholderText.addAttribute(NSAttributedString.Key.foregroundColor, value: UIColor.white, range:NSRange(location:0,length:Name.count))    // Color
            passworddogrulaTextField.attributedPlaceholder = whitePlaceholderText
        
    

    @IBOutlet weak var signUpButton: UIButton!
    @IBOutlet weak var errorLabel: UILabel!    

    let Button = UIButton(type: .custom)
    let Button1 = UIButton(type: .custom)


    override func viewDidLoad() 
        super.viewDidLoad()
        self.hideKeyboardWhenTappedAround()
        setUpElements()
        show_hide_password(textfield: passwordTextField)
        show_hide_password1(textfield: passworddogrulaTextField)
        self.passwordTextField.delegate = self
        self.passworddogrulaTextField.delegate = self
        self.emailTextField.delegate = self
        self.lastNameTextField.delegate = self
        self.firstNameTextField.delegate = self
    
    

    func textFieldShouldReturn(_ textField: UITextField) -> Bool 
    vself.view.endEditing(true)
        return false
    

    func show_hide_password(textfield: UITextField) 
        textfield.rightViewMode = .unlessEditing
        Button.setImage(UIImage(systemName: "eye.slash.fill"), for: .normal)
        Button.imageEdgeInsets = UIEdgeInsets(top: 5, left: -24, bottom: 5, right: 15)
        Button.frame = CGRect(x: CGFloat(textfield.frame.size.width - 25), y: CGFloat(5), width: CGFloat(15), height: CGFloat(25))
        Button.addTarget(self, action: #selector(self.btnVisibilityClicked), for: .touchUpInside)
        textfield.rightView = Button
        textfield.rightViewMode = .always
    
    func show_hide_password1(textfield: UITextField) 
        textfield.rightViewMode = .unlessEditing
        Button1.setImage(UIImage(systemName: "eye.slash.fill"), for: .normal)
        Button1.imageEdgeInsets = UIEdgeInsets(top: 5, left: -24, bottom: 5, right: 15)
        Button1.frame = CGRect(x: CGFloat(textfield.frame.size.width - 25), y: CGFloat(5), width: CGFloat(15), height: CGFloat(25))
        Button1.addTarget(self, action: #selector(self.btnVisibilityClicked1), for: .touchUpInside)
        textfield.rightView = Button1
        textfield.rightViewMode = .always
    

    @IBAction func btnVisibilityClicked(_ sender: Any) 
        (sender as! UIButton).isSelected = !(sender as! UIButton).isSelected
        if (sender as! UIButton).isSelected
            self.passwordTextField.isSecureTextEntry = false
            Button.setImage(UIImage(systemName: "eye.fill"), for: .normal)
         else 
            self.passwordTextField.isSecureTextEntry = true
            Button.setImage(UIImage(systemName: "eye.slash.fill"), for: .normal)
        
   
    @IBAction func btnVisibilityClicked1(_ sender: Any) 
        (sender as! UIButton).isSelected = !(sender as! UIButton).isSelected
        if (sender as! UIButton).isSelected
            self.passworddogrulaTextField.isSecureTextEntry = false
            Button1.setImage(UIImage(systemName: "eye.fill"), for: .normal)
         else 
            self.passworddogrulaTextField.isSecureTextEntry = true
            Button1.setImage(UIImage(systemName: "eye.slash.fill"), for: .normal)
        
    

    func setUpElements()
        errorLabel.alpha = 0
        Utilities.styleTextField(firstNameTextField)
        Utilities.styleTextField(lastNameTextField)
        Utilities.styleTextField(emailTextField)
        Utilities.styleTextField(passwordTextField)
        Utilities.styleTextField(passworddogrulaTextField)
        Utilities.styleFilledButton(signUpButton)
    

这里是故事板的屏幕截图Connection for the text fields and the screenshot of sign up page storyboard 以及故事板和视图控制器之间的连接：

即使我声明了约束，底线似乎也不正确。我应该怎么做才能让它看起来正确？

这是错误外观的截图：The appearance of the text field in iPhone 12 Pro Max

下面是Xcode for iPhone 11模拟器中正确外观的截图：The simulator of iPhone 11 and the correct appearance

感谢您的帮助！这是草稿的video link。

【参考方案1】：

您在布局设置之前设置这些。如果你在 UIView 类中有你的视图，你可以把它们放在 layoutSubviews() 由于您是在 viewController 中设置这些，因此将 setUpElements() 放入 viewDidAppear() 可能会解决您的问题。

【讨论】：

感谢您的帮助！还有一个问题。当我将 setUpElements() 添加到 viewDidAppear() 中时，设置元素会有一点延迟。如何避免这种延迟？

我认为 viewDidLayoutSubviews() 最适合你