为@environmentObject设置SceneDelegate时的编译器警告

Question

我正在尝试实现@environmentObject以将数组从一个选项卡中的视图传递到另一个选项卡中的另一个视图。

我收到黄色编译器警告：

从未使用了不可变价价值的初始化'reportview'； 考虑替换为“ _”或删除

删除

中

import UIKit
import SwiftUI

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    var questionsAsked = QuestionsAsked()

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

        ProductsStore.shared.initializeProducts()

        if let windowScene = scene as? UIWindowScene {
          let window = UIWindow(windowScene: windowScene)
          window.rootViewController = UIHostingController(rootView: MotherView().environmentObject(ViewRouter()))
          self.window = window
          window.makeKeyAndVisible()
        }

        let reportView = ReportView().environmentObject(questionsAsked)
    }
}

。

import Foundation

class QuestionsAsked: ObservableObject {
    @Published var sectionThings = [SectionThing]()
    @Published var memoryPalaceThings = [MemoryPalaceThing]()
}

SceneDelegate

@EnvironmentObject var questionsAsked: QuestionsAsked

在

我将数据传递到这样的数据：

questionsAsked.sectionThings = testSectionThings ?? []

在将数据传递给我的位置：

@EnvironmentObject var questionsAsked: QuestionsAsked

然后我如下：

totalThings += questionsAsked.sectionThings.count
totalThings += questionsAsked.memoryPalaceThings.count

Answer 1

这里的问题是，该行无用，因为它不会在现场中呈现。唯一提出的视图是MotherView。为了将问题传递给向下视图，您只需像其他.environmentObject那样附加它。因此，这应该读取：

class SceneDelegate: UIResponder, UIWindowSceneDelegate {

    var window: UIWindow?
    // this really need to be @StateObject´s
    @StateObject var viewRouter = ViewRouter()
    @StateObject var questionsAsked = QuestionsAsked()

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

        ProductsStore.shared.initializeProducts()

        if let windowScene = scene as? UIWindowScene {
          let window = UIWindow(windowScene: windowScene)
            //Inject them here into the MotherView
            window.rootViewController = UIHostingController(rootView: MotherView().environmentObject(viewRouter).environmentObject(questionsAsked))
          self.window = window
          window.makeKeyAndVisible()
        }
    }
}

在MotherView和降序视图中，您可以通过@environmentObject包装访问它们。