Swiftui NavigationView 定时器延迟

Question

In my app I navigate to a page (say, page 2), then wish to show an animation (and nothing else) on the page, before executing and moving to a new view using NavigationView. In other words, I'd like the NavigationView destination view to load after a delay timer (say 3 seconds), without the user having to click a button. During that 3 seconds, the animation will be running. The animation and the NavigationView work fine on their own, but my current solution requires the user to click a button/text to move to the destination view, which is a little clunky. I can't find a solution anywhere. Any help would be greatly appreciated. Thanks!

Answer 1

This should work:

struct MyView: View {
    @State var pushNewView: Bool = false
    
    var body: some View {
        NavigationView {
            NavigationLink(isActive: $pushNewView) {
                Text("Second View")
            } label: {
                Text("First View") //Replace with some animation content
            }
        }
        .onAppear {
            Timer.scheduledTimer(withTimeInterval: 3, repeats: false) { _ in
                pushNewView = true
            }
        }
    }
}

Answer 2

Alternatively:

struct MyView: View {
    @State var pushNewView: Bool = false
    
    var body: some View {
        NavigationView {
            NavigationLink(isActive: $pushNewView) {
                Text("Second View")
            } label: {
                Text("First View") //Replace with some animation content
            }
        }
        .onAppear {
            DispatchQueue.main.asyncAfter(deadline: .now() + 3) {
                pushNewView = true
            }
        }
    }
}

Answer 3

You can use DelayedNavigationLink , see implementation below. Usage example:

var body: some View {
    VStack {
        Text("Navigation link will run in 3 seconds")
        DelayedNavigationLink(delay: .seconds(3)) {
            Text("Destination view")
        }
    }
}

Implementation:

struct DelayedNavigationLink<Destination: View, Label: View>: View {
    @State private var linkIsActive = false

    private let delay: DispatchTimeInterval
    private var destination: () -> Destination
    private var label: () -> Label

    init(delay: DispatchTimeInterval, destination: @escaping () -> Destination) where Label == EmptyView {
        self.init(delay: delay, destination: destination, label: EmptyView.init)
    }

    init(delay: DispatchTimeInterval, destination: @escaping () -> Destination, label: @escaping () -> Label) {
        self.delay = delay
        self.destination = destination
        self.label = label
    }

    var body: some View {
        NavigationLink(isActive: $linkIsActive, destination: destination, label: label)
            .onAppear {
                DispatchQueue.main.asyncAfter(deadline: .now() + delay) {
                    linkIsActive = true
                }
            }
    }
}