RU: Исследуем жизненный цикл ViewController. EN: Let's study the ViewController life cycle

LifeCycleViewController.swift

final class ViewController: UIViewController {
    private let name = "🖥️"
    private let infoLabel: UILabel = {
        let label = UILabel()
        label.text = "AppDelegate Life Cycle"
        label.translatesAutoresizingMaskIntoConstraints = false
        return label
    }()
    
    private let switchButton: UIButton = {
        let button = UIButton(type: .system)
        button.setTitle("Switch to Second VC", for: .normal)
        button.translatesAutoresizingMaskIntoConstraints = false
        return button
    }()
    
    init() {
        super.init(nibName: nil, bundle: nil)
        Logger.shared.log("\(name) - 1) \(#function)")
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    override func loadView() {
        Logger.shared.log("\(name) - 2) \(#function)")
        view = UIView()
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        Logger.shared.log("\(name) - 3) \(#function)")
        view.backgroundColor = .blue
        view.addSubview(infoLabel)
        view.addSubview(switchButton)
        
        // Настройка автолэйаута для infoLabel и switchButton
        NSLayoutConstraint.activate([
            infoLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            infoLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            
            switchButton.centerXAnchor.constraint(equalTo: view.centerXAnchor),
            switchButton.topAnchor.constraint(equalTo: infoLabel.bottomAnchor, constant: 20)
        ])
        
        switchButton.addTarget(self, action: #selector(switchToSecondVC), for: .touchUpInside)
    }
    
    @objc private func switchToSecondVC() {
        let secondVC = SecondViewController()
        navigationController?.pushViewController(secondVC, animated: true)
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        Logger.shared.log("\(name) - 4) \(#function)")
    }
    
    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        Logger.shared.log("\(name) - 5) \(#function)")
    }
    
    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        Logger.shared.log("\(name) - 6) \(#function)")
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        Logger.shared.log("\(name) - 7) \(#function)")
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        Logger.shared.log("\(name) - 8) \(#function)")
    }
    
    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)
        Logger.shared.log("\(name) - 9) \(#function)")
    }
    
    deinit {
        Logger.shared.log("\(name) - 10) \(#function)")
    }
}

SecondViewController.swift

final class SecondViewController: UIViewController {
    private let name = "🖥️🖥️"

    init() {
        super.init(nibName: nil, bundle: nil)
        Logger.shared.log("\(name) - 1) \(#function)")
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    override func loadView() {
        Logger.shared.log("\(name) - 2) \(#function)")
        view = UIView()
        view.backgroundColor = .green
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        Logger.shared.log("\(name) - 3) \(#function)")
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        Logger.shared.log("\(name) - 4) \(#function)")
    }

    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        Logger.shared.log("\(name) - 5) \(#function)")
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        Logger.shared.log("\(name) - 6) \(#function)")
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        Logger.shared.log("\(name) - 7) \(#function)")
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        Logger.shared.log("\(name) - 8) \(#function)")
    }

    override func viewDidDisappear(_ animated: Bool) {
        super.viewDidDisappear(animated)
        Logger.shared.log("\(name) - 9) \(#function)")
    }

    deinit {
        Logger.shared.log("\(name) - 10) \(#function)")
    }
}

default.mp4