UIViewControllerRepresentable ignoresSafeArea不工作

Question

import SwiftUI
import UIKit

extension Color {
    static var random: Color {
        return Color (
            red: .random(in: 0...1),
            green: .random(in: 0...1),
            blue: .random(in: 0...1)
        )
    }
}

struct ContentView: View {
    let pages = (0..<3).map { _ in Color.random }
    var body: some View {
        PageView(pages: pages)
            .ignoresSafeArea()
    }
}

struct PageView<Page: View>: View {
    var pages: [Page]
    @State private var currentPage = 0

    var body: some View {
        PageViewController(pages: pages, currentPage: $currentPage)
    }
}

struct PageViewController<Page: View>: UIViewControllerRepresentable {
    var pages: [Page]
    @Binding var currentPage: Int

    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    func makeUIViewController(context: Context) -> UIPageViewController {
        let pageViewController = UIPageViewController(
            transitionStyle: .scroll,
            navigationOrientation: .horizontal)
        pageViewController.dataSource = context.coordinator
        pageViewController.delegate = context.coordinator
        return pageViewController
    }

    func updateUIViewController(_ pageViewController: UIPageViewController, context: Context) {
        pageViewController.setViewControllers(
            [context.coordinator.controllers[currentPage]], direction: .forward, animated: true)
    }

    class Coordinator: NSObject, UIPageViewControllerDataSource, UIPageViewControllerDelegate {
        var parent: PageViewController
        var controllers = [UIViewController]()

        init(_ pageViewController: PageViewController) {
            parent = pageViewController
            controllers = parent.pages.map { UIHostingController(rootView: $0) }
        }

        func pageViewController(
            _ pageViewController: UIPageViewController,
            viewControllerBefore viewController: UIViewController) -> UIViewController? {
                guard let index = controllers.firstIndex(of: viewController) else {
                    return nil
                }
                if index == 0 {
                    return controllers.last
                }
                return controllers[index - 1]
            }

        func pageViewController(
            _ pageViewController: UIPageViewController,
            viewControllerAfter viewController: UIViewController) -> UIViewController? {
                guard let index = controllers.firstIndex(of: viewController) else {
                    return nil
                }
                if index + 1 == controllers.count {
                    return controllers.first
                }
                return controllers[index + 1]
            }

        func pageViewController(
            _ pageViewController: UIPageViewController,
            didFinishAnimating finished: Bool,
            previousViewControllers: [UIViewController],
            transitionCompleted completed: Bool) {
                if completed,
                   let visibleViewController = pageViewController.viewControllers?.first,
                   let index = controllers.firstIndex(of: visibleViewController) {
                    parent.currentPage = index
                }
            }
    }
}

​

​

Answer 1

它不仅适用于容器，而且也适用于内部视图(填充外部容器)，因为默认情况下，每个视图都尊重安全区域。

所以解决办法是

init(_ pageViewController: PageViewController) {
    parent = pageViewController
    controllers = parent.pages.map { 
        UIHostingController(rootView: $0.ignoresSafeArea())  // << here !!
    }
}

用Xcode 13.3 / iOS 15.4测试