UIViewControllerLifecycleView.swift

import SwiftUI

// ...
    SomeView()
        .background(UIViewControllerLifecycleView(
            onViewWillAppear: {
            }, onViewDidAppear: {
            }, onViewWillDisappear: {
            }, onViewDidDisappear: {
            })
        )
// ...

private struct UIViewControllerLifecycleView: UIViewControllerRepresentable {

    class Coordinator: UIViewController {
        let onViewWillAppear: (() -> Void)?
        let onViewDidAppear: (() -> Void)?
        let onViewWillDisappear: (() -> Void)?
        let onViewDidDisappear: (() -> Void)?

        init(onViewWillAppear: (() -> Void)?, onViewDidAppear: (() -> Void)?, onViewWillDisappear: (() -> Void)?, onViewDidDisappear: (() -> Void)?) {
            self.onViewWillAppear = onViewWillAppear
            self.onViewDidAppear = onViewDidAppear
            self.onViewWillDisappear = onViewWillDisappear
            self.onViewDidDisappear = onViewDidDisappear
            super.init(nibName: nil, bundle: nil)
        }
        required init?(coder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
        override func viewWillAppear(_ animated: Bool) {
            super.viewWillAppear(animated)
            onViewWillAppear?()
        }
        override func viewDidAppear(_ animated: Bool) {
            super.viewDidAppear(animated)
            onViewDidAppear?()
        }
        override func viewWillDisappear(_ animated: Bool) {
            super.viewWillDisappear(animated)
            onViewWillDisappear?()
        }
        override func viewDidDisappear(_ animated: Bool) {
            super.viewDidDisappear(animated)
            onViewDidDisappear?()
        }
    }

    var onViewWillAppear: (() -> Void)?
    var onViewDidAppear: (() -> Void)?
    var onViewWillDisappear: (() -> Void)?
    var onViewDidDisappear: (() -> Void)?

    func makeUIViewController(context: UIViewControllerRepresentableContext<UIViewControllerLifecycleView>) -> UIViewController {
        context.coordinator
    }
    func makeCoordinator() -> UIViewControllerLifecycleView.Coordinator {
        Coordinator(onViewWillAppear: onViewWillAppear, onViewDidAppear: onViewDidAppear, onViewWillDisappear: onViewWillDisappear, onViewDidDisappear: onViewDidDisappear)
    }
    func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<UIViewControllerLifecycleView>) {
    }
}