Question

使用Xcode 11 GM Seed编写一些SwiftUI代码，我遇到了我不明白的Swift错误。

struct MainViewController: View {
    var body: some View {
        VStack {
            Text("Hello World!")
        }
    }
}

extension MainViewController : UIViewControllerRepresentable {
    func makeUIViewController(context: UIViewControllerRepresentableContext<MainViewController>) -> UINavigationController {
        return UINavigationController()
    }

    func updateUIViewController(_ uiViewController: UINavigationController, context: UIViewControllerRepresentableContext<MainViewController>) {

    }
}

此报告：

'UIViewControllerRepresentable' requires the types 'some View' and 'Never' be equivalent

Answer 1

我错过了ViewController和View之间的分隔。错误是说视图控制器不能有返回视图的主体。

这有效：

struct MainView : View {
    var body: some View {
        VStack {
            Text("Hello World!")
        }
    }
}

struct MainViewController : UIViewControllerRepresentable {
    func makeUIViewController(context: UIViewControllerRepresentableContext<MainViewController>) -> UIHostingController<MainView> {
        return UIHostingController(rootView: MainView())
    }

    func updateUIViewController(_ uiViewController: UIHostingController<MainView>, context: UIViewControllerRepresentableContext<MainViewController>) {

    }
}

然后实例化它：

let viewController = UIHostingController<MainViewController>(rootView:MainViewController())

UIViewControllerRepresentable要求类型“ some View”和“ Never”等效

1 个答案: