如何在 SwiftUI 中将变量从一个视图传递到另一个视图

Question

I'm trying to pass one variable from one view to another in SwiftUI. I have a reset button in which I want to set the variable to zero in the other view.

I have tried creating a new struct in view one and accessing that variable in view 2.

// View 1

@State var count = MyNumber.number

// Body of app

Button(action: {self.count = self.count-10}) {
                    Text("-")   
                }
Text("\(count)")

struct MyNumber {
    static var number = 0
}

// View 2

 @State var countit = MyNumber.number

// Body

Button(action: {self.countit = 0}) {
            Text("Reset")
            }

Text in view one is still showing the number that was computed in View 1

Answer 1

If View2 is being used in View1 you could do something like this:

View1:

struct FirstView: View {
    @State var count = 0
    var body: some View {
        VStack{
            Text("\(self.count)")
            Button(action:
                {self.count = self.count-10})
            {
                Text("-")
            }
            SecondView(count: self.$count)
        }
    }
}

And View2:

struct SecondView: View {
    @Binding var count: Int
    var body: some View {
        Button(action: {self.count = 0}) {
            Text("Reset")
        }
    }
}

Edit

If they are completely different views and need single source of truth you could use an observableObject/EnvironmentVariables. The best way would be to add the environment variable to the ContentView where it's first defined in the SceneDelegate

ContentView().environmentObject(SourceOfTruth())

Here is SourceOfTruth:

class SourceOfTruth: ObservableObject{
    @Published var count = 0
}

Then you could use EnvironmentObjects to the other views: Here is ContentView :

struct ContentView: View {
    @EnvironmentObject var truth: SourceOfTruth
    var body: some View {
        VStack {
            FirstView()
            SecondView()
        }
    }
}

Here is FirstView :

struct FirstView: View {
    @EnvironmentObject var truth: SourceOfTruth
    var body: some View {
       VStack{
        Text("\(self.truth.count)")
           Button(action:
            {self.truth.count = self.truth.count-10})
           {
               Text("-")
           }
       }
    }
}

Here is SecondView :

struct SecondView: View {
    @EnvironmentObject var truth: SourceOfTruth
    var body: some View {
        Button(action: {self.truth.count = 0}) {
            Text("Reset")
        }
    }
}