Swiftui tabbar selecteditem change

During my first attempts with Swift UI, I tried desperately to figure out how to select the active tab programmatically. The trick is in the binding.

@State public var selection = 0

With a click on the button selection tells the value one. Since Selection is directly linked to the tab bar, the active tab item changes as desired.

Button("Go",action: {self.selection = 1})

Binding is the access token that you can pass to allow direct read and write access to the value without granting possession (in the sense of retaining a reference type) or copying (for a value type).

When the user selects a tab in the tab view, he or she changes the value unilaterally via binding and assigns the corresponding .tag(…) to the selectedTab variable. This works the same way for @State and ObservableObject.

The programmer can also assign a value to this selectedTab variable at any time – and the TabView immediately switches the displayed tab.

This is the key to programmatic navigation in SwiftUI.

Here is an example that you can copy / paste directly to play around with it.

import SwiftUI

struct ContentView: View {
    @State public var selection = 0

    let defaults = UserDefaults.standard

    var body: some View {
        TabView(selection: $selection){
            VStack {
                Text("First View")
                Button("Go",action: {self.selection = 1})
            }
            .font(.title)
            .tabItem {
                VStack {
                    Image("first")
                    Text("First")
                }
            }
            .tag(0)
            Text("Second View")

                .font(.title)
                .tabItem {
                    VStack {
                        HStack{
                            Image("second")
                            Text("Second")
                        }
                    }
            }
            .tag(1)
        }
    }
}



struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}