ios - 简单的 SwiftUI 模态演示和通过 @StateObject 关闭

Question

Xcode 12 测试版 6 (12A8189n)

iPhone 11、iOS 14.0 模拟器

在给定的代码示例中， CreateSomethingView 的表示有效，但是解雇它不起作用。我对使用 @StateObject 完成这项工作特别感兴趣。并避免 @State完全。

import SwiftUI

@main
struct ModalPresentationApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}

final class ContentModel: ObservableObject {
    @Published
    var isPresenting = false
}

struct ContentView: View {
    @StateObject
    var contentModel = ContentModel()

    var body: some View {
        NavigationView {
            Text("ContentView")
                .toolbar {
                    ToolbarItem(placement: .navigationBarTrailing) {
                        Button(action: {
                            contentModel.isPresenting.toggle()
                        }, label: {
                            Image(systemName: "plus.circle")
                        })
                        .sheet(isPresented: $contentModel.isPresenting) {
                            CreateSomethingView(isPresented: $contentModel.isPresenting)
                        }
                    }
                }
        }
    }
}

struct CreateSomethingView: View {
    @Binding
    var isPresented: Bool

    var body: some View {
        NavigationView {
            Text("CreateSomethingView")
                .toolbar {
                    ToolbarItem(placement: .navigationBarLeading) {
                        Button(action: {
                            isPresented = false
                        }, label: {
                            Image(systemName: "xmark.circle.fill")
                        })
                    }
                }
        }
    }
}

Answer 1

只需在适当的位置附上工作表(嗯......只是根据经验，任何 *bar(s) 都不是 View 间绑定(bind)的好地方)
这是修复。使用 Xcode 12b5/iOS 14 准备和测试

var body: some View {
    NavigationView {
        Text("ContentView")
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    Button(action: {
                        contentModel.isPresenting = true
                    }, label: {
                        Image(systemName: "plus.circle")
                    })
                }
            }
    }
    .sheet(isPresented: $contentModel.isPresenting) {
        CreateSomethingView(isPresented: $contentModel.isPresenting)
    }
}