Adds viewDidAppear callback to SwiftUI

OnDidAppearSwiftUI

struct ViewControllerLifecycleHandler: UIViewControllerRepresentable {
    func makeCoordinator() -> ViewControllerLifecycleHandler.Coordinator {
        Coordinator(onDidAppear: onDidAppear)
    }

    let onDidAppear: () -> Void
    
    func makeUIViewController(context: UIViewControllerRepresentableContext<ViewControllerLifecycleHandler>) -> UIViewController {
        context.coordinator
    }

    func updateUIViewController(_ uiViewController: UIViewController, context: UIViewControllerRepresentableContext<ViewControllerLifecycleHandler>) {
    }

    typealias UIViewControllerType = UIViewController

    class Coordinator: UIViewController {
        let onDidAppear: (() -> Void)?

        init(onDidAppear: (() -> Void)?) {
            self.onDidAppear = onDidAppear

            super.init(nibName: nil, bundle: nil)
        }

        required init?(coder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }
        
        override func viewDidAppear(_ animated: Bool) {
            super.viewDidAppear(animated)
           (onDidAppear ?? {})()
        }
    }
}

struct DidAppearModifier: ViewModifier {
    let onDidAppearCallback: (() -> Void)?

    func body(content: Content) -> some View {
        content
            .background(ViewControllerLifecycleHandler(onDidAppear: onDidAppearCallback ?? {}))
    }
}

extension View {
    func onDidAppear(_ perform: @escaping () -> Void) -> some View {
        self.modifier(DidAppearModifier(onDidAppearCallback: perform))
    }
}

Not working for me... I still dont see the animations...

.onDidAppear { withAnimation(.easeOut(duration: 0.5)) { print("IS ANIMATING: \(isAnimating)") isAnimating = true } }

@Alexminator99 Are you sure it has something to do with the modifier itself? Have you tried debugging the code to make sure the animation code is called?

If so, could you please provide some technical details (Xcode version, iOS version, Device type: physical or emulator)?

Yeah, sure... @alongotv

var body: some View {
        TabView {
            ForEach(0..<5) { item in 
                FruitCardView()
            } //: FOREACH
        } //: TABVIEW
        .tabViewStyle(PageTabViewStyle())
        .padding(.vertical, 20)
    }

// FRUITCARDVIEW
var body: some View {
        ZStack {
            VStack(spacing: 20) {
                // IMAGE
                ...
                // TITLE
                ...
                // HEADLINE
                ...
                // START
                ...
            } //: VSTACK
        } //: ZSTACK
        .onDidAppear {
            withAnimation(.easeOut(duration: 0.5)) {
                print("IS ANIMATING: \(isAnimating)")
                isAnimating = true
            }
        }
        
    }

Where u get this log:

IS ANIMATING: false
IS ANIMATING: false
IS ANIMATING: true
IS ANIMATING: false

As you can see, the 3 view in the TabView is created before it even appears...

@Alexminator99 It looks like something might be broken in TabView once again - I can't receive viewDidAppear callback in the UIViewControllerRepresentable if applied to View inside the TabView (iOS 16.1.1 physical device). Although, viewWillAppear works just fine. Unfortunately, I was unable to find a workaround, other than using that modifier outside the TabView or putting the TabView's child into a ".sheet{}". Either way, it's a pity that this gist wasn't helpful for you. Sorry!

@Alexminator99 It looks like something might be broken in TabView once again - I can't receive viewDidAppear callback in the UIViewControllerRepresentable if applied to View inside the TabView (iOS 16.1.1 physical device). Although, viewWillAppear works just fine. Unfortunately, I was unable to find a workaround, other than using that modifier outside the TabView or putting the TabView's child into a ".sheet{}". Either way, it's a pity that this gist wasn't helpful for you. Sorry!

I already reported the issue. Thks anyway, the gist is really interesting ;)