Custom Tab Bar with variable number of tabs in SwiftUI

Question

I'm trying to replicate the tab bar in the iPad version of Safari, which looks like this:

(Is there a third party library which does this? I can't find one)

I'm using the code below. Which results in this:

I guess I need to turn the Views into arrays somehow, and have a button (on the tab, or page) to add and remove tabs. Any idea how to do this?

import SwiftUI

struct TabLabel : View {

      var text : String
      var imageName : String
      var color : Color

      var body : some View {
            VStack() {
                  Image(systemName: imageName)
                  Text(text).font(.caption)
            }.foregroundColor(color)
      }
}

struct TabButton : View {
      @Binding var currentSelection : Int
      var selectionIndex : Int
      var label : TabLabel

      var body : some View {
            Button(action: { self.currentSelection = self.selectionIndex }) { label }.opacity(selectionIndex == currentSelection ? 0.5 : 1.0)
      }
}

struct CustomTabBarView : View {


      var view1 : SomeView1
      var view2 : SomeView2
      var view3 : SomeView3

      @State var currentSelection : Int = 1
      var body : some View {

            let label1 = TabLabel(text: "First", imageName:  "1.square.fill", color: Color.red)
            let label2 = TabLabel(text: "Second", imageName:  "2.square.fill", color: Color.purple)
            let label3 = TabLabel(text: "Third", imageName:  "3.square.fill", color: Color.blue)

            let button1 = TabButton(currentSelection: $currentSelection, selectionIndex: 1, label: label1)
            let button2 = TabButton(currentSelection: $currentSelection, selectionIndex: 2, label: label2)
            let button3 = TabButton(currentSelection: $currentSelection, selectionIndex: 3, label: label3)


            return VStack() {
                
                HStack() {
                      button1
                      Spacer()
                      button2
                      Spacer()
                      button3

                }.padding(.horizontal, 48)
                      .frame(height: 48.0)
                      .background(Color(UIColor.systemGroupedBackground))
                
                  Spacer()

                  if currentSelection == 1 {
                        view1
                  }
                  else if currentSelection == 2 {
                        view2
                  }
                  else if currentSelection == 3 {
                        view3
                  }

                  Spacer()

                  
            }

      }
}



struct ContentView: View {
    @State private var showGreeting = true
    var body: some View {
        
                let view1 = VStack() {
                      Text("The First Tab").font(.headline)
                      Image(systemName: "triangle").resizable().aspectRatio(contentMode: .fit).frame(width: 100)
                }

                let view2 = Text("Another Tab").font(.headline)
                let view3 = Text("The Final Tab").font(.headline)

                return CustomTabBarView(view1: view1, view2: view2, view3: view3)
          }
}

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

ChrisR · Accepted Answer

I honestly love @Scott Matthewman's answer! It inspired me to try an implementation – I included Scotts to do points as remarks :)

Model:

struct SinglePage: Identifiable, Equatable {
    var id: UUID
    var title: String
    var image: String
    
    init(title: String, image: String) {
        self.id = UUID()
        self.title = title
        self.image = image
    }
    
    static func == (lhs: SinglePage, rhs: SinglePage) -> Bool {
        return lhs.id == rhs.id
    }
}

class PagesModel: ObservableObject {
    
    // an ordered collection of pages, each with a title and image
    @Published var pages: [SinglePage]
    // a concept of which page in that collection is active
    @Published var selectedPage: SinglePage?
    
    init() {
        // Test Data
        pages = []
        for i in 0..<4 {
            let item = SinglePage(title: "Tab \(i)", image: "\(i).circle")
            self.pages.append(item)
        }
        selectedPage = pages.first ?? nil
    }
    
    // your user can choose which page should be the active one
    func select(page: SinglePage) {
        selectedPage = page
    }
    
    // they can add a new page to the collection
    func add(title: String, image: String) {
        let item = SinglePage(title: title, image: image)
        self.pages.append(item)
    }
    
    // they can remove an existing page from the collection
    func delete(page: SinglePage) {
        pages.removeAll(where: {$0 == page})
    }
}

Views:

struct ContentView: View {
    
    @StateObject var tabs = PagesModel()
    
    var body: some View {
        VStack {
            // A list of horizontal tabs loops through the ordered collection of pages and renders each one
            HStack {
                ForEach(tabs.pages) { page in
                    TabLabelView(page: page)
                }
                // A separate button, when tapped, can add a new page to the collection
                AddTabButton()
            }
            ActiveTabContentView(page: tabs.selectedPage)
        }
        .environmentObject(tabs)
    }
}

struct TabLabelView: View {
    
    @EnvironmentObject var tabs: PagesModel
    
    let page: SinglePage
    
    var body: some View {
        HStack {
            // Each tab has a close button which, when tapped, removes it from the pages collection
            Button {
                tabs.delete(page: page)
            } label: {
                Image(systemName: "xmark")
            }
            
            Text(page.title)
        }
        .font(.caption)
        .padding(5)
//        .frame(height: 50)
        .background(
            Color(page == tabs.selectedPage ? .red : .gray)
        )
        // Each tab has a button action which, when tapped, sets that button to be the active one
        .onTapGesture {
            tabs.select(page: page)
        }
    }
}

// A separate button, when tapped, can add a new page to the collection
struct AddTabButton: View {
    
    @EnvironmentObject var tabs: PagesModel

    var body: some View {
        Button {
            tabs.add(title: "New", image: "star")
        } label: {
            Label("Add", systemImage: "add")
        }
        .font(.caption)
        .padding(5)
    }
}



struct ActiveTabContentView: View {
    
    @EnvironmentObject var tabs: PagesModel
    
    let page: SinglePage?
    
    var body: some View {
        if let page = page {
            VStack {
                Spacer()
                Text(page.title)
                Image(systemName: page.image)
                    .font(.largeTitle)
                Spacer()
            }
        }
    }
}

Custom Tab Bar with variable number of tabs in SwiftUI

Answers (2)

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