[Tab#509] Fix flickering in demo and warning 'Modifying state during …

…view update'.

core/Sources/Components/Tab/View/SwiftUI/TabView.swift

@@ -11,7 +11,8 @@ import SwiftUI
 /// TabView is the similar to a SegmentControl
 public struct TabView: View {
     private let intent: TabIntent
-    @ObservedObject private var viewModel: TabViewModel<TabItemContent>
+    private var viewModel: TabViewModel<TabItemContent>
+    @ObservedObject private var containerViewModel = TabContainerViewModel()
     @Binding private var selectedIndex: Int
     @Environment(\.isEnabled) private var isEnabled: Bool
 
@@ -71,7 +72,6 @@ public struct TabView: View {
         self._selectedIndex = selectedIndex
         let viewModel = TabViewModel(
             theme: theme,
-            apportionsSegmentWidthsByContent: false,
             content: content, 
             tabSize: tabSize
         )
@@ -82,7 +82,7 @@ public struct TabView: View {
     public var body: some View {
         let viewModel = self.viewModel.setIsEnabled(self.isEnabled)
 
-        if viewModel.apportionsSegmentWidthsByContent {
+        if self.containerViewModel.apportionsSegmentWidthsByContent {
             TabApportionsSizeView(viewModel: viewModel, intent: self.intent, selectedIndex: self.$selectedIndex)
         } else {
             TabEqualSizeView(viewModel: viewModel, intent: self.intent, selectedIndex: self.$selectedIndex)
@@ -92,6 +92,7 @@ public struct TabView: View {
     // MARK: - Public view modifiers
     /// Indicates whether the control attempts to adjust segment widths based on their content widths.
     public func apportionsSegmentWidthsByContent(_ value: Bool) -> Self {
+        self.containerViewModel.apportionsSegmentWidthsByContent = value
         self.viewModel.apportionsSegmentWidthsByContent = value
         return self
     }

core/Sources/Components/Tab/ViewModel/TabContainerViewModel.swift

@@ -0,0 +1,13 @@
+//
+//  TabContainerViewModel.swift
+//  SparkCore
+//
+//  Created by Michael Zimmermann on 06.06.24.
+//  Copyright © 2024 Adevinta. All rights reserved.
+//
+
+import SwiftUI
+
+final class TabContainerViewModel: ObservableObject {
+    @Published var apportionsSegmentWidthsByContent: Bool = false
+}

spark/Demo/Classes/View/Components/Tab/SwiftUI/TabComponent.swift

@@ -143,19 +143,6 @@ struct TabComponent: View {
                 .disabled(self.allDisabled == .selected)
             }
         )
-        .onChange(of: self.numberOfTabs) { _ in
-            self.redraw()
-        }
-        .onChange(of: self.stateVals) { _ in
-            self.redraw()
-        }
-    }
-
-    func redraw() {
-        self.equalSize.toggle()
-        DispatchQueue.main.async {
-            self.equalSize.toggle()
-        }
     }
 
     func badge() -> BadgeView? {