用swift5写一个注册登陆页面

以下是一个简单的注册登录页面的 Swift 5 代码示例：

import UIKit

class ViewController: UIViewController {

    // 注册页面 UI 控件
    @IBOutlet weak var registerUsernameTextField: UITextField!
    @IBOutlet weak var registerPasswordTextField: UITextField!
    @IBOutlet weak var registerConfirmPasswordTextField: UITextField!
    @IBOutlet weak var registerButton: UIButton!
    
    // 登录页面 UI 控件
    @IBOutlet weak var loginUsernameTextField: UITextField!
    @IBOutlet weak var loginPasswordTextField: UITextField!
    @IBOutlet weak var loginButton: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        // 隐藏键盘
        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(hideKeyboard))
        view.addGestureRecognizer(tapGesture)
    }
    
    @objc func hideKeyboard() {
        view.endEditing(true)
    }

    @IBAction func registerButtonTapped(_ sender: Any) {
        guard let username = registerUsernameTextField.text, !username.isEmpty else {
            showAlert(message: "请输入用户名")
            return
        }
        
        guard let password = registerPasswordTextField.text, !password.isEmpty else {
            showAlert(message: "请输入密码")
            return
        }
        
        guard let confirmPassword = registerConfirmPasswordTextField.text, !confirmPassword.isEmpty else {
            showAlert(message: "请确认密码")
            return
        }
        
        if password != confirmPassword {
            showAlert(message: "两次输入的密码不一致")
            return
        }
        
        // 在此处添加注册代码
        
        showAlert(message: "注册成功")
    }
    
    @IBAction func loginButtonTapped(_ sender: Any) {
        guard let username = loginUsernameTextField.text, !username.isEmpty else {
            showAlert(message: "请输入用户名")
            return
        }
        
        guard let password = loginPasswordTextField.text, !password.isEmpty else {
            showAlert(message: "请输入密码")
            return
        }
        
        // 在此处添加登录代码
        
        showAlert(message: "登录成功")
    }
    
    func showAlert(message: String) {
        let alert = UIAlertController(title: nil, message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "确定", style: .default, handler: nil))
        present(alert, animated: true, completion: nil)
    }
}

在 Storyboard 中，可以将上述代码中的 UI 控件拖拽到相应的视图控制器中。注册按钮和登录按钮可以分别绑定到 `registerButtonTapped` 和 `loginButtonTapped` 方法上。同时，还需要将 `hideKeyboard` 方法绑定到视图上以实现点击空白处隐藏键盘的功能。