如何更改整个应用程序的tintColor？斯威夫特用户界面

Question

因此，我在我的应用程序中支持三个主题，每个主题都有不同的色调颜色。我正在使用 @EnvironmetObject 来跟踪更改。但是，我无法在 SceneDelegate.swift 文件上使用它，因为应用程序崩溃了。此外，accentColor不是一个选项，因为它不会改变警报tintColor。我该怎么做？

这是一些代码：

SceneDelegate.swift 文件

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

@EnvironmentObject var userData: UserData

var window: UIWindow?

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
    // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
    // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).

    // Create the SwiftUI view that provides the window contents.
    let contentView = TasksView()

    // Use a UIHostingController as window root view controller.
    if let windowScene = scene as? UIWindowScene {
        let window = UIWindow(windowScene: windowScene)
        window.rootViewController = UIHostingController(rootView: contentView.environmentObject(UserData()))
        self.window = window
        window.makeKeyAndVisible()

        window.tintColor = userData.selectedTheme.tintColor
    }
}

当应用程序启动时，这种方法将会崩溃，因为它无法在其祖先中找到@EnvironmentObject。

ContentView.swift 文件

struct ContentView: View {

    @EnvironmentObject var userData: UserData

    var body: some View {
        NavigationView{
            List(userData.tasks) { task in
                TaskRow(taskTitle: task.title, taskDetail: task.detail)
            }
            .navigationBarTitle(Text("Tasks"), displayMode: .automatic)

            .navigationBarItems(
                leading: NavigationLink(destination: SettingsView(), label: {
                    Image(systemName: "gear").imageScale(.large)
                }),
                trailing: NavigationLink(destination: AddTaskView(), label: {
                    Image(systemName: "plus").imageScale(.large)
                })
            )
        }.navigationViewStyle(StackNavigationViewStyle())
         .accentColor(userData.selectedTheme.accentColor)
    }
}

这种方法对我来说也不起作用，因为它不会改变警报的色调颜色等。

图片

如果我使用accentColor，这就是我得到的结果

---

这就是我想要实现的目标

Answer 1

更新：将此演示发布到 GitHub - DemoWindowTint

下面的演示是使用如何在 SwiftUI 视图中访问自己的窗口？tintColor中提供的方法在设置窗口（由所有子视图继承）时创建的。。

在演示中，我使用了NavigationView几个NavigationLinks并Button显示了Alert。

测试如下

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?


    func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {

        if let windowScene = scene as? UIWindowScene {
            let window = UIWindow(windowScene: windowScene)

            let contentView = ContentView()
                .environment(\.hostingWindow, { [weak window] in
                    return window })

            window.rootViewController = UIHostingController(rootView: contentView)

            self.window = window
    ...

struct ContentView: View {
    @Environment(\.hostingWindow) var hostingWindow
   ... // body can be any

    .onAppear {
            // can be loaded from UserDefaults here, and later changed on any action
            self.hostingWindow()?.tintColor = UIColor.red
    }