UIKit Auto Layout programmatically

import UIKit

class ProfileViewController: UIViewController {
    private let profileImageView: UIImageView = {
        let imageView = UIImageView()
        imageView.contentMode = .scaleAspectFill
        imageView.clipsToBounds = true
        imageView.layer.cornerRadius = 50
        imageView.translatesAutoresizingMaskIntoConstraints = false
        return imageView
    }()

    private let nameLabel: UILabel = {
        let label = UILabel()
        label.font = .systemFont(ofSize: 24, weight: .bold)
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    private let bioLabel: UILabel = {
        let label = UILabel()
        label.font = .systemFont(ofSize: 16)
        label.textColor = .secondaryLabel
        label.numberOfLines = 0
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()

    private lazy var followButton: UIButton = {
        let button = UIButton(type: .system)
        button.setTitle("Follow", for: .normal)
        button.titleLabel?.font = .systemFont(ofSize: 16, weight: .semibold)
        button.backgroundColor = .systemBlue
        button.setTitleColor(.white, for: .normal)
        button.layer.cornerRadius = 8
        button.translatesAutoresizingMaskIntoConstraints = false
        button.addTarget(self, action: #selector(followTapped), for: .touchUpInside)
        return button
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        setupUI()
    }

    private func setupUI() {
        view.backgroundColor = .systemBackground

        view.addSubview(profileImageView)
        view.addSubview(nameLabel)
        view.addSubview(bioLabel)
        view.addSubview(followButton)

        NSLayoutConstraint.activate([
            // Profile image
            profileImageView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20),
            profileImageView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            profileImageView.widthAnchor.constraint(equalToConstant: 100),
            profileImageView.heightAnchor.constraint(equalToConstant: 100),

            // Name label
            nameLabel.topAnchor.constraint(equalTo: profileImageView.bottomAnchor, constant: 16),
            nameLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
            nameLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20),

            // Bio label
            bioLabel.topAnchor.constraint(equalTo: nameLabel.bottomAnchor, constant: 8),
            bioLabel.leadingAnchor.constraint(equalTo: nameLabel.leadingAnchor),
            bioLabel.trailingAnchor.constraint(equalTo: nameLabel.trailingAnchor),

            // Follow button
            followButton.topAnchor.constraint(equalTo: bioLabel.bottomAnchor, constant: 24),
            followButton.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
            followButton.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20),
            followButton.heightAnchor.constraint(equalToConstant: 44)
        ])
    }

    @objc private func followTapped() {
        print("Follow button tapped")
    }
}

// MARK: - Stack View Example
class StackViewExample: UIViewController {
    private lazy var stackView: UIStackView = {
        let stack = UIStackView()
        stack.axis = .vertical
        stack.spacing = 16
        stack.alignment = .fill
        stack.distribution = .fill
        stack.translatesAutoresizingMaskIntoConstraints = false
        return stack
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .systemBackground

        view.addSubview(stackView)

        NSLayoutConstraint.activate([
            stackView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor, constant: 20),
            stackView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 20),
            stackView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -20)
        ])

        // Add arranged subviews
        let titleLabel = createLabel(text: "Title", fontSize: 24, weight: .bold)
        let descriptionLabel = createLabel(text: "Description text", fontSize: 16)
        let button = createButton(title: "Action")

        stackView.addArrangedSubview(titleLabel)
        stackView.addArrangedSubview(descriptionLabel)
        stackView.addArrangedSubview(button)
    }

    private func createLabel(text: String, fontSize: CGFloat, weight: UIFont.Weight = .regular) -> UILabel {
        let label = UILabel()
        label.text = text
        label.font = .systemFont(ofSize: fontSize, weight: weight)
        label.numberOfLines = 0
        return label
    }

    private func createButton(title: String) -> UIButton {
        let button = UIButton(type: .system)
        button.setTitle(title, for: .normal)
        button.backgroundColor = .systemBlue
        button.setTitleColor(.white, for: .normal)
        button.layer.cornerRadius = 8
        button.heightAnchor.constraint(equalToConstant: 44).isActive = true
        return button
    }
}