多个工作表(isPresented :) 在 SwiftUI 中不起作用 [英] Multiple sheet(isPresented:) doesn't work in SwiftUI

问题描述

我有这个 ContentView 有两个不同的模式视图，所以我都使用 sheet(isPresented:) ，但似乎只有最后一个被呈现.我怎么能解决这个问题?还是无法在 SwiftUI 中的视图上使用多个工作表?

I have this ContentView with two different modal views, so I'm using sheet(isPresented:) for both, but as it seems only the last one gets presented. How could I solve this issue? Or is it not possible to use multiple sheets on a view in SwiftUI?

struct ContentView: View {
    
    @State private var firstIsPresented = false
    @State private var secondIsPresented = false
    
    var body: some View {
        NavigationView {
            VStack(spacing: 20) {
                Button("First modal view") {
                    self.firstIsPresented.toggle()
                }
                Button ("Second modal view") {
                    self.secondIsPresented.toggle()
                }
            }
            .navigationBarTitle(Text("Multiple modal view problem"), displayMode: .inline)
            .sheet(isPresented: $firstIsPresented) {
                    Text("First modal view")
            }
            .sheet(isPresented: $secondIsPresented) {
                    Text("Only the second modal view works!")
            }
        }
    }
}

以上代码编译时没有警告(Xcode 11.2.1).

The above code compiles without warnings (Xcode 11.2.1).

推荐答案

UPD

从 Xcode 12.5.0 Beta 3(2021 年 3 月 3 日)开始，这个问题不再有意义，因为现在可以有多个 .sheet(isPresented:)或 .fullScreenCover(isPresented:) 一行，问题中显示的代码将正常工作.

UPD

Starting from Xcode 12.5.0 Beta 3 (3 March 2021) this question makes no sense anymore as it is possible now to have multiple .sheet(isPresented:) or .fullScreenCover(isPresented:) in a row and the code presented in the question will work just fine.

尽管如此，我发现这个答案仍然有效，因为它很好地组织了工作表并使代码干净且更具可读性 - 您有一个事实来源，而不是几个独立的布尔值

Nevertheless I find this answer still valid as it organizes the sheets very well and makes the code clean and much more readable - you have one source of truth instead of a couple of independent booleans

最好的方法，也适用于 iOS 14:

Best way to do it, which also works for iOS 14:

enum ActiveSheet: Identifiable {
    case first, second
    
    var id: Int {
        hashValue
    }
}

struct YourView: View {
    @State var activeSheet: ActiveSheet?

    var body: some View {
        VStack {
            Button {
                activeSheet = .first
            } label: {
                Text("Activate first sheet")
            }

            Button {
                activeSheet = .second
            } label: {
                Text("Activate second sheet")
            }
        }
        .sheet(item: $activeSheet) { item in
            switch item {
            case .first:
                FirstView()
            case .second:
                SecondView()
            }
        }
    }
}

在此处阅读更多信息:https://developer.apple.com/documentation/swiftui/view/sheet(item:ondismiss:content:)

要隐藏工作表，只需设置 activeSheet = nil

To hide the sheet just set activeSheet = nil

奖励:如果您希望您的工作表全屏显示，请使用相同的代码，但不要使用 .sheet 编写 .fullScreenCover

Bonus: If you want your sheet to be fullscreen, then use the very same code, but instead of .sheet write .fullScreenCover

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