feat(ui): collapse the home navigation bar at the top of the feed

DashWallet/Sources/UI/Home/HomeViewController.swift

@@ -36,14 +36,24 @@ class HomeViewController: DWBasePayViewController, NavigationBarDisplayable {
     private var homeView: HomeView!
     weak var delegate: (HomeViewControllerDelegate & DWWipeDelegate)?
 
+    /// True while the home feed is scrolled to the top — the navigation
+    /// bar stays hidden there so the balance header owns the space; it
+    /// slides in once the balances scroll away. Read by
+    /// `BaseNavigationController` through `isNavigationBarHidden` on
+    /// every navigation transition, so pushed screens keep their bar and
+    /// popping back restores the current scroll-derived state.
+    private var hidesNavigationBarAtTop = true
+
     #if DASHPAY
     var isBackButtonHidden: Bool = false
     private var invitationSetup: DWInvitationSetupState?
     private var avatarView: DWDPAvatarView!
     #else
     var isBackButtonHidden: Bool = true
     #endif
-
+
+    var isNavigationBarHidden: Bool { hidesNavigationBarAtTop }
+
     override var payModel: any DWPayModelProtocol {
         get { return model.payModel }
         set { }
@@ -93,6 +103,12 @@ class HomeViewController: DWBasePayViewController, NavigationBarDisplayable {
         super.viewWillAppear(animated)
 
         navigationController?.navigationBar.applyOpaqueAppearance(with: UIColor.dw_dashNavigationBlue(), shadowColor: .clear)
+        // Apply the scroll-derived bar state directly too —
+        // `BaseNavigationController.willShow` reads `isNavigationBarHidden`
+        // on transitions, but the home tab must also start hidden on
+        // first display and stay correct if hosted outside that
+        // navigation controller subclass.
+        navigationController?.setNavigationBarHidden(hidesNavigationBarAtTop, animated: animated)
     }
 
     override func viewDidAppear(_ animated: Bool) {
@@ -649,6 +665,21 @@ extension HomeViewController: HomeViewDelegate {
         present(controller, animated: true, completion: nil)
     }
 
+    func homeViewDidChangeTopBarVisibility(shouldShow: Bool) {
+        // At the top of the feed the navigation bar stays hidden so the
+        // balance header gets the full height; once the user scrolls the
+        // balances away, the bar (Dash logo + avatar) slides in.
+        // `isNavigationBarHidden` keeps `BaseNavigationController`'s
+        // willShow pass consistent with the live state, so pushes show
+        // the bar for their own screens and pops restore ours.
+        let shouldHide = !shouldShow
+        guard hidesNavigationBarAtTop != shouldHide else { return }
+        hidesNavigationBarAtTop = shouldHide
+        if navigationController?.topViewController === self {
+            navigationController?.setNavigationBarHidden(shouldHide, animated: true)
+        }
+    }
+
     func homeViewShowInternalTransfer(direction: InternalTransferDirection, source: InternalTransferSource) {
         // Sheet, not push: a push drags the blue navigation header along;
         // the sheet keeps the transfer form on its own background with

DashWallet/Sources/UI/Home/Views/HomeView.swift

@@ -25,6 +25,9 @@ import DashUIKit
 protocol HomeViewDelegate: AnyObject {
     func homeViewShowSyncingStatus()
     func homeViewShowInternalTransfer(direction: InternalTransferDirection, source: InternalTransferSource)
+    /// Scroll-derived chrome: false at the top of the feed (bar hidden,
+    /// balance header owns the space), true once the user scrolls down.
+    func homeViewDidChangeTopBarVisibility(shouldShow: Bool)
 
 #if DASHPAY
     func homeView(_ homeView: HomeView, didUpdateProfile identity: DSBlockchainIdentity?, unreadNotifications: UInt)
@@ -159,6 +162,22 @@ extension HomeView: HomeHeaderViewDelegate {
     }
 }
 
+/// Scroll thresholds (pt scrolled down) for showing/hiding the
+/// navigation bar. Two values (hysteresis) so the bar doesn't flicker
+/// when the user rests exactly on the boundary. File-scoped because
+/// `HomeViewContent` is generic (no static stored properties).
+private let kTopBarShowThreshold: CGFloat = 100
+private let kTopBarHideThreshold: CGFloat = 60
+
+/// Scroll offset of the home feed's top sentinel in the scroll view's
+/// coordinate space — feeds the collapsing top bar.
+private struct HomeScrollOffsetKey: PreferenceKey {
+    static var defaultValue: CGFloat = 0
+    static func reduce(value: inout CGFloat, nextValue: () -> CGFloat) {
+        value = nextValue()
+    }
+}
+
 struct HomeViewContent<Content: View>: View {
     @State private var selectedTxDataItem: TransactionListDataItem? = nil
     @State private var showFilterDialog: Bool = false
@@ -179,15 +198,16 @@ struct HomeViewContent<Content: View>: View {
     @ViewBuilder var headerView: () -> Content
 
     private let topOverscrollSize: CGFloat = 1000 // Fixed value for top overscroll area
-
+
+    @State private var isTopBarShown = false
 
     var body: some View {
         ZStack {
             ScrollView {
                 ZStack { Color.navigationBarColor } // Top overscroll area
                     .frame(height: topOverscrollSize)
                     .padding(EdgeInsets(top: -topOverscrollSize, leading: 0, bottom: 0, trailing: 0))
-                
+
                 LazyVStack(pinnedViews: [.sectionHeaders]) {
                     HomeBalanceView(
                         viewModel: balanceModel,
@@ -279,6 +299,33 @@ struct HomeViewContent<Content: View>: View {
                     }
                 }
                 .padding(EdgeInsets(top: -20, leading: 0, bottom: 0, trailing: 0))
+                // Scroll sentinel as a background so it adds no layout
+                // (a zero-height sibling would still get the scroll
+                // content's implicit spacing and open a light gap in the
+                // blue header). minY is ~0 at rest and goes negative as
+                // the user scrolls down; drives the collapsing top bar.
+                .background(
+                    GeometryReader { proxy in
+                        Color.clear.preference(
+                            key: HomeScrollOffsetKey.self,
+                            value: proxy.frame(in: .named("homeScroll")).minY)
+                    }
+                )
+            }
+            .coordinateSpace(name: "homeScroll")
+            .onPreferenceChange(HomeScrollOffsetKey.self) { minY in
+                // minY == 0 at rest; more negative the further down the
+                // user has scrolled.
+                let scrolled = -minY
+                if isTopBarShown {
+                    if scrolled < kTopBarHideThreshold {
+                        isTopBarShown = false
+                        delegate?.homeViewDidChangeTopBarVisibility(shouldShow: false)
+                    }
+                } else if scrolled > kTopBarShowThreshold {
+                    isTopBarShown = true
+                    delegate?.homeViewDidChangeTopBarVisibility(shouldShow: true)
+                }
             }
         }
         .sheet(item: $selectedTxDataItem) { item in