SwiftUI关闭模态

Question

由于SwiftUI是声明性的，因此没有dismiss方法。如何在上添加一个关闭/关闭按钮DetailView？

struct DetailView: View {
  var body: some View {
  Text("Detail")
  }
}

struct ContentView : View {
  var body: some View {
  PresentationButton(Text("Click to show"), destination: DetailView())
  }
}

Answer 1

您可以presentationMode在模态视图中使用环境变量并调用self.presentaionMode.wrappedValue.dismiss()以消除模态：

struct ContentView: View {

  @State private var showModal = false

  var body: some View {
    Button(action: {
        self.showModal = true
    }) {
        Text("Show modal")
    }.sheet(isPresented: self.$showModal) {
        ModalView()
    }
  }
}


struct ModalView: View {

  @Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>

  var body: some View {
    Group {
      Text("Modal view")
      Button(action: {
         self.presentationMode.wrappedValue.dismiss()
      }) {
        Text("Dismiss")
      }
    }
  }
}

Answer 2

在 Xcode Beta 5 中，另一种方法是在启动模态的视图中使用 @State，并在模态视图中添加绑定以控制模态的可见性。这不需要您进入@EnvironmentpresentationMode 变量。

struct MyView : View {
    @State var modalIsPresented = false

    var body: some View {
        Button(action: {self.modalIsPresented = true})  {
            Text("Launch modal view")
        }
        .sheet(isPresented: $modalIsPresented, content: {
            MyModalView(isPresented: self.$modalIsPresented)
        })
    }
}


struct MyModalView : View {
    @Binding var isPresented: Bool

    var body: some View {
        Button(action: {self.isPresented = false})  {
            Text("Close modal view")
        }
    }
}

Answer 3

这是一种消除呈现视图的方法。

struct DetailView: View {
    @Binding
    var dismissFlag: Bool

    var body: some View {
        Group {
            Text("Detail")
            Button(action: {
                self.dismissFlag.toggle()
            }) {
                Text("Dismiss")
            }
        }

    }
}

struct ContentView : View {
    @State var dismissFlag = false

    var body: some View {
        Button(action: {
            self.dismissFlag.toggle()
        })
        { Text("Show") }
            .presentation(!dismissFlag ? nil :
                Modal(DetailView(dismissFlag: $dismissFlag)) {
                print("dismissed")
            })
    }
}

Answer 4

Swift 5.5 和 SwiftUI 3 中的新增功能：

@Environment(\.dismiss) var dismiss

然后在函数或主体代码中的某个位置，只需调用：

self.dismiss()

Answer 5

似乎对于Xcode 11 Beta 7（在Xcode的版本11M392r上）来说，它略有不同。

@Environment(\.presentationMode) var presentation


Button(action: { self.presentation.wrappedValue.dismiss() }) { Text("Dismiss") }

Answer 6

您可以实现这一点。

struct view: View {
    @Environment(\.isPresented) private var isPresented

    private func dismiss() {
        isPresented?.value = false
    }
}

Answer 7

Beta 5中现在有一种非常干净的方法来执行此操作。

import SwiftUI

struct ModalView : View {
    // In Xcode 11 beta 5, 'isPresented' is deprecated use 'presentationMode' instead
    @Environment(\.presentationMode) var presentationMode: Binding<PresentationMode>
    var body: some View {
        Group {
            Text("Modal view")
            Button(action: { self.presentationMode.wrappedValue.dismiss() }) { Text("Dismiss") }
        }
    }
}

struct ContentView : View {
    @State var showModal: Bool = false
    var body: some View {
        Group {
            Button(action: { self.showModal = true }) { Text("Show modal via .sheet modifier") }
                .sheet(isPresented: $showModal, onDismiss: { print("In DetailView onDismiss.") }) { ModalView() }
        }
    }
}

Answer 8

如果进入则自动弹出，如果进入Navigation则自动关闭Modal

只需presentationMode从目标视图中的环境中dismiss获取wrappedValue：

struct DestinationView: View {
    @Environment(\.presentationMode) private var presentationMode

    var body: some View {
        Button("Dismiss") {
            self.presentationMode.wrappedValue.dismiss()
        }
    }
}

演示（弹出/关闭）

Answer 9

iOS 15

而不是presentationMode我们现在可以使用DismissAction.

这是文档中的一个示例：

struct SheetView: View {
    @Environment(\.dismiss) var dismiss

    var body: some View {
        NavigationView {
            SheetContents()
                .toolbar {
                    Button("Done") {
                        dismiss()
                    }
                }
        }
    }
}