如何忽略 SwiftUI 模态背景，或使模态背景清晰/透明？

Question

目前，我们为 swiftUI 模式提供了免费的不透明白色/黑色背景。无论如何，有没有办法删除免费的不透明颜色并使模态视图透明？

在下图中，即使呈现模式，最终结果也应该能够看到图像。

Answer 1

基于此代码片段，您可以创建viewcontroller扩展并修改您的演示文稿。这是修改后的代码：

 struct ViewControllerHolder {
    weak var value: UIViewController?
    init(_ value: UIViewController?) {
        self.value = value
    }
}

struct ViewControllerKey: EnvironmentKey {
    static var defaultValue: ViewControllerHolder { return ViewControllerHolder(UIApplication.shared.windows.first?.rootViewController ) }
}

extension EnvironmentValues {
    var viewController: ViewControllerHolder {
        get { return self[ViewControllerKey.self] }
        set { self[ViewControllerKey.self] = newValue }
    }
}

extension UIViewController {
    func present<Content: View>(presentationStyle: UIModalPresentationStyle = .automatic, transitionStyle: UIModalTransitionStyle = .coverVertical, animated: Bool = true, completion: @escaping () -> Void = {}, @ViewBuilder builder: () -> Content) {
        let toPresent = UIHostingController(rootView: AnyView(EmptyView()))
        toPresent.modalPresentationStyle = presentationStyle
        toPresent.rootView = AnyView(
            builder()
                .environment(\.viewController, ViewControllerHolder(toPresent))
        )

        toPresent.view.backgroundColor = .clear // This line is modified
        self.present(toPresent, animated: animated, completion: completion)
    }
}

您的 SwiftUI ContentView：

struct ContentView: View {

    @Environment(\.viewController) private var viewControllerHolder: ViewControllerHolder
    private var viewController: UIViewController? {
        self.viewControllerHolder.value
    }

    var body: some View {
        ZStack {
            Color.red
            Button(action: {
                self.viewController?.present(builder: {
                    Text("OK")
                })
            }) {
               Text("Present me!")
            }
        }
    }
}