swift输出一个登陆界面app代码

以下是一个简单的登陆界面app代码，使用Swift语言编写：

import UIKit

class LoginViewController: UIViewController {

    // MARK: - Properties
    
    let logoImageView: UIImageView = {
        let imageView = UIImageView()
        imageView.image = UIImage(named: "logo")
        imageView.contentMode = .scaleAspectFit
        imageView.translatesAutoresizingMaskIntoConstraints = false
        return imageView
    }()
    
    let emailTextField: UITextField = {
        let textField = UITextField()
        textField.placeholder = "Email"
        textField.borderStyle = .roundedRect
        textField.translatesAutoresizingMaskIntoConstraints = false
        return textField
    }()
    
    let passwordTextField: UITextField = {
        let textField = UITextField()
        textField.placeholder = "Password"
        textField.borderStyle = .roundedRect
        textField.isSecureTextEntry = true
        textField.translatesAutoresizingMaskIntoConstraints = false
        return textField
    }()
    
    let loginButton: UIButton = {
        let button = UIButton(type: .system)
        button.setTitle("Login", for: .normal)
        button.backgroundColor = .systemBlue
        button.setTitleColor(.white, for: .normal)
        button.layer.cornerRadius = 5
        button.translatesAutoresizingMaskIntoConstraints = false
        return button
    }()
    
    // MARK: - Lifecycle Methods
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
        configureUI()
    }
    
    // MARK: - Helper Methods
    
    func configureUI() {
        view.addSubview(logoImageView)
        view.addSubview(emailTextField)
        view.addSubview(passwordTextField)
        view.addSubview(loginButton)
        
        logoImageView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        logoImageView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 50).isActive = true
        logoImageView.widthAnchor.constraint(equalToConstant: 150).isActive = true
        logoImageView.heightAnchor.constraint(equalToConstant: 150).isActive = true
        
        emailTextField.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        emailTextField.topAnchor.constraint(equalTo: logoImageView.bottomAnchor, constant: 50).isActive = true
        emailTextField.widthAnchor.constraint(equalToConstant: 250).isActive = true
        emailTextField.heightAnchor.constraint(equalToConstant: 40).isActive = true
        
        passwordTextField.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        passwordTextField.topAnchor.constraint(equalTo: emailTextField.bottomAnchor, constant: 20).isActive = true
        passwordTextField.widthAnchor.constraint(equalToConstant: 250).isActive = true
        passwordTextField.heightAnchor.constraint(equalToConstant: 40).isActive = true
        
        loginButton.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        loginButton.topAnchor.constraint(equalTo: passwordTextField.bottomAnchor, constant: 50).isActive = true
        loginButton.widthAnchor.constraint(equalToConstant: 200).isActive = true
        loginButton.heightAnchor.constraint(equalToConstant: 40).isActive = true
    }
}

这个登陆界面包含一个Logo图片、一个Email输入框、一个密码输入框和一个登陆按钮。使用Auto Layout来设置它们的位置和大小。可以根据需要对它们进行修改和调整。