A secondary tab navigation view that appears on the top of the screen. Smooth animations.

The motivation comes from the deficiency of our existing navigation options. A tab bar provides primary navigation, and if a secondary tab is needed, it requires us to make custom views with stack navigations. This secondary tab navigation is a compact and customizable solution that leverages the power of SwiftUI to make ends meet.

The screen recording is from the preview code in SecondaryTabView.swift. Refer to that for the full details.

1. Define an item type representing each tab's view model. A simple enum is usually sufficient.

private enum Item: Int, SecondaryTabViewItem {
    case first = 0
    case second
    case third
    case fourth

    var text: String {
        switch self {
        case .first: return "First"
        case .second: return "Second"
        case .third: return "Third"
        case .fourth: return "Fourth name too long"
        }
    }
}

2. In your container view, declare a selection state.

@State private var selection: Item = .first

3. Now you can use the secondary tab view as below.

a. You want to bind your selection state. b. Declare each tab's content view identify each with .tabItem(for: <Instance of Item>). In the example below the content is a simple Text view, but it can be anything you want. c. Provide a label for each tab. You may customize the appearance based on the selection state. d. There are customizations for the selection underline and view modifier.

SecondaryTabView(
    selection: $selection,
    content: {
        Text(verbatim: "First")
            .tabItem(for: Item.first)

        Text(verbatim: "Second")
            .tabItem(for: Item.second)

        Text(verbatim: "Third")
            .tabItem(for: Item.third)

        Text(verbatim: "Fourth name too long")
            .tabItem(for: Item.fourth)
    },
    label: { item, isSelected in
        Text(
            item.text
        )
        .foregroundColor(isSelected ? Color.orange : Color.primary)
    },
    underline: {
        Color.orange
        .frame(height: 2)
    },
    barViewModifier: ShadowModifier()
)