Ios SwiftUI检测顶级和安全区域插图

你可以从GeometryReader获得安全区域插图.您可以将GeometryReader放在视图层次 struct 的最顶端，也可以直接放在WindowGroup { ... }中.然后，您可以向下发送带有环境密钥的插图.

WindowGroup {
    GeometryReader { geo in
        // putting the text directly in a GeometryReader makes it align to the top left
        // which is why I am nesting it in a ZStack that covers the whole screen here
        // any other view that fills all the available space works too
        ZStack {
            ContentView() // the rest of the app is here 
                .environment(\.safeAreaInsets, geo.safeAreaInsets)
        }.frame(maxWidth: .infinity, maxHeight: .infinity)
    }
}

struct ContentView: View {
    @Environment(\.safeAreaInsets) var insets
    var body: some View {
        Text("\(insets.top)")
    }
}

private struct SafeAreaInsetsKey: EnvironmentKey {
    static var defaultValue: EdgeInsets = .init()
}

extension EnvironmentValues {
    var safeAreaInsets: EdgeInsets {
        get { self[SafeAreaInsetsKey.self] }
        set { self[SafeAreaInsetsKey.self] = newValue }
    }
}

请注意，您需要预览整个GeometryReader个，才能在Xcode预览中工作.可以将几何体读取器和ZStack封装到视图修改器中，如下所示，以便可以在预览中方便地使用它:

extension View {
    func readSafeAreaInsets() -> some View {
        GeometryReader { geo in
            ZStack {
                self.environment(\.safeAreaInsets, geo.safeAreaInsets)
            }.frame(maxWidth: .infinity, maxHeight: .infinity)
        }
    }
}

#Preview {
    ContentView().readSafeAreaInsets()
}