Why can't swiftui distinguish 2 different environment objects?

问题

I have this code and would expected a b as Text.

Result: a a -> see screenshot. What am I doing wrong?

import SwiftUI

class PublishString : ObservableObject {

    init(string: String) {
        self.string = string
        print(self.string)
    }

    @Published var string : String = "a"
}

struct ContentView: View {

    @EnvironmentObject var text1 : PublishString
    @EnvironmentObject var text2 : PublishString

    var body: some View {
        VStack {
            Text(text1.string)
            Text(text2.string)
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView().environmentObject(PublishString(string: "a"))
        .environmentObject(PublishString(string: "b"))
    }
}

and ...this works:

class PublishString : ObservableObject {

    init(string: String) {
        self.string = string
        print(self.string)
    }

    @Published var string : String = "a"
}

class PublishString2 : ObservableObject {

    init(string: String) {
        self.string = string
        print(self.string)
    }

    @Published var string : String = "a"
}

struct ContentView: View {

    @EnvironmentObject var text1 : PublishString
    @EnvironmentObject var text2 : PublishString2

    var body: some View {
        VStack {
            Text(text1.string)
            Text(text2.string)
        }
    }
}

回答1:

As noted by Asperi in the comment, SwiftUI identifies Environment Objects by the type (the class definition you have used). It looks for an object of that type and uses the first one it finds.

One option is to have multiple properties on the one object that you can access (this would mean two separate String properties in your case.

Further information is available on the Apple documentation.

来源：https://stackoverflow.com/questions/61804474/why-cant-swiftui-distinguish-2-different-environment-objects

标签

swiftui