Question

我想在应用程序中有条件地显示不同的视图-如果某个布尔值为true，则将显示一个视图。如果为假，将显示其他视图。此布尔值在ObservableObject类内，并且从将要显示的视图之一中更改。

PracticeStatus.swift（父视图）

import Foundation
import SwiftUI
import Combine

class PracticeStatus: ObservableObject  {
    @Published var showResults:Bool = false
}

PracticeView.swift（父视图）

struct PracticeView: View {
    @EnvironmentObject var practiceStatus: PracticeStatus

    var body: some View {
        VStack {
            if practiceStatus.showResults {
                ResultView()
            } else {
                QuestionView().environmentObject(PracticeStatus())
            }
        }
    }
}

QuestionView.swift

struct QuestionView: View {
    @EnvironmentObject var practiceStatus: PracticeStatus

    var body: some View {
        VStack {
            ...
            Button(action: {
                self.practiceStatus.showResults = true
            }) { ... }
            ...
        }
    }
}

但是，此代码无效。当按下QuestionView中的按钮时，不会显示ResultView。有人有解决方案吗？谢谢！

Answer 1

您是否尝试过编译代码？有几个基本错误：

变量practice在PracticeView中不存在。您是说practiceStatus吗？
变量userData在QuestionView中不存在。您是说practiceStatus吗？
您正在从PracticeView内部呼叫PracticeView！您肯定会得到堆栈溢出；-)您不是在说QuestionView吗？

以下是有效代码：

import Foundation
import SwiftUI
import Combine

class PracticeStatus: ObservableObject  {
    @Published var showResults:Bool = false
}

struct ContentView: View {
    @State private var flag = false

    var body: some View {
        PracticeView().environmentObject(PracticeStatus())
    }
}

struct PracticeView: View {
    @EnvironmentObject var practiceStatus: PracticeStatus

    var body: some View {
        VStack {
            if practiceStatus.showResults {
                ResultView()
            } else {
                QuestionView()
            }
        }
    }
}

struct QuestionView: View {
    @EnvironmentObject var practiceStatus: PracticeStatus

    var body: some View {
        VStack {

            Button(action: {
                self.practiceStatus.showResults = true
            }) {
                Text("button")
            }
        }
    }
}

struct ResultView: View {
    @State private var flag = false

    var body: some View {
        Text("RESULTS")
    }
}

SwiftUI-使用'ObservableObject'和@EnvironmentObject有条件地显示视图

1 个答案: