问为@EnvironmentObject设置SceneDelegate时编译器警告
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Stack Overflow用户

提问于 2022-07-01 09:45:09

回答 1查看 29关注 0票数 -2

我试图实现@EnvironmentObject，将数组从一个选项卡中的View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：

从未使用不可变值“reportView”的

初始化；考虑将其替换为“_”或删除它

在SceneDelegate.swift中

这是我的SceneDelegate.swift：

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)
    }
}

这是我的ObservabelObject：

import Foundation

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

我用：

@EnvironmentObject var questionsAsked: QuestionsAsked

在我看来，这将生成要传递的数据。

我传递的数据如下：

questionsAsked.sectionThings = testSectionThings ?? []

在要传递数据的视图中，我有：

@EnvironmentObject var questionsAsked: QuestionsAsked

然后，我按以下方式访问：

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

swift

swiftui

observableobject

environmentobject

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回答 1

Stack Overflow用户

发布于 2022-07-01 12:08:08

这里的问题是，这条线是无用的，因为它不会出现在现场。唯一显示的视图是MotherView。为了将questionsAsked向下传递到该视图，您只需像其他.environmentObject一样追加它。因此，应改为：

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()
        }
    }
}