Hide floating tab bar on iPad when scrolling

Wikipedia/Code/ArticleViewController.swift

@@ -1178,6 +1178,16 @@ class ArticleViewController: ThemeableViewController, HintPresenting, UIScrollVi
         updateTableOfContentsHighlightIfNecessary()
 
         calculateNavigationBarHiddenState(scrollView: webView.scrollView)
+
+        if #available(iOS 18.0, *) {
+            let velocity = scrollView.panGestureRecognizer.velocity(in: scrollView).y
+
+            if velocity < 0 { // Scrolling down
+                tabBarController?.setTabBarHidden(true, animated: true)
+            } else if velocity > 0 { // Scrolling up
+                tabBarController?.setTabBarHidden(false, animated: true)
+            }
+        }
     }
 
     func scrollViewDidScrollToTop(_ scrollView: UIScrollView) {

Wikipedia/Code/ColumnarCollectionViewController.swift

@@ -1,8 +1,12 @@
-import Foundation
 import WMF
+import WMFComponents
 
-class ColumnarCollectionViewController: ThemeableViewController, ColumnarCollectionViewLayoutDelegate, UICollectionViewDataSourcePrefetching, CollectionViewFooterDelegate, HintPresenting {
+class ColumnarCollectionViewController: ThemeableViewController, ColumnarCollectionViewLayoutDelegate, UICollectionViewDataSourcePrefetching, CollectionViewFooterDelegate, HintPresenting, WMFNavigationBarHiding {
+    var topSafeAreaOverlayView: UIView?
 
+    var topSafeAreaOverlayHeightConstraint: NSLayoutConstraint?
+
+
     enum HeaderStyle {
         case sections
         case exploreFeedDetail
@@ -383,8 +387,53 @@ class ColumnarCollectionViewController: ThemeableViewController, ColumnarCollect
         return min(max(_maxViewed, percentViewed), 100)
     }
 
+    // MARK: – Scroll View methods
+
     func scrollViewDidScroll(_ scrollView: UIScrollView) {
         _maxViewed = max(_maxViewed, percentViewed)
+
+        guard UIDevice.current.userInterfaceIdiom == .pad, #available(iOS 18.0, *) else { return }
+
+        let velocity = scrollView.panGestureRecognizer.velocity(in: scrollView).y
+        if velocity < -30 {
+            tabBarController?.setTabBarHidden(true, animated: true)
+        } else if velocity > 30 {
+            tabBarController?.setTabBarHidden(false, animated: true)
+        }
+
+        calculateNavigationBarHiddenState(scrollView: scrollView)
+    }
+
+    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
+        handleShortContentBounce(scrollView, immediately: !decelerate)
+    }
+
+    func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
+        handleShortContentBounce(scrollView, immediately: true)
+    }
+
+    private func handleShortContentBounce(_ scrollView: UIScrollView, immediately: Bool) {
+        guard UIDevice.current.userInterfaceIdiom == .pad,
+              #available(iOS 18.0, *) else { return }
+
+        let visibleHeight = scrollView.bounds.height
+                           - scrollView.adjustedContentInset.top
+                           - scrollView.adjustedContentInset.bottom
+        let contentHeight = scrollView.contentSize.height
+
+        if contentHeight <= visibleHeight {
+            let showAction = {
+                self.tabBarController?.setTabBarHidden(false, animated: true)
+            }
+
+            if immediately {
+                showAction()
+            } else {
+                DispatchQueue.main.async {
+                    showAction()
+                }
+            }
+        }
     }
 
     // MARK: - CollectionViewFooterDelegate

Wikipedia/Code/ExploreViewController.swift

@@ -4,7 +4,7 @@ import CocoaLumberjackSwift
 import WMFComponents
 import WMFData
 
-class ExploreViewController: ColumnarCollectionViewController, ExploreCardViewControllerDelegate, CollectionViewUpdaterDelegate, ImageScaleTransitionProviding, DetailTransitionSourceProviding, MEPEventsProviding, WMFNavigationBarConfiguring, WMFNavigationBarHiding {
+class ExploreViewController: ColumnarCollectionViewController, ExploreCardViewControllerDelegate, CollectionViewUpdaterDelegate, ImageScaleTransitionProviding, DetailTransitionSourceProviding, MEPEventsProviding, WMFNavigationBarConfiguring {
 
     public var presentedContentGroupKey: String?
     public var shouldRestoreScrollPosition = false
@@ -57,9 +57,6 @@ class ExploreViewController: ColumnarCollectionViewController, ExploreCardViewCo
             return existingYirCoordinator
     }
 
-    var topSafeAreaOverlayHeightConstraint: NSLayoutConstraint?
-    var topSafeAreaOverlayView: UIView?
-
     private var presentingSearchResults: Bool = false
 
     // MARK: - Lifecycle
@@ -348,7 +345,7 @@ class ExploreViewController: ColumnarCollectionViewController, ExploreCardViewCo
         }
     }
 
-    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
+    override func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
         logFeedImpressionAfterDelay()
     }
 

Wikipedia/Code/HistoryViewController.swift

@@ -5,10 +5,7 @@ import WMFData
 import CocoaLumberjackSwift
 
 @objc(WMFHistoryViewController)
-class HistoryViewController: ArticleFetchedResultsViewController, WMFNavigationBarConfiguring, WMFNavigationBarHiding {
-
-    var topSafeAreaOverlayHeightConstraint: NSLayoutConstraint?
-    var topSafeAreaOverlayView: UIView?
+class HistoryViewController: ArticleFetchedResultsViewController, WMFNavigationBarConfiguring {
 
     // Properties needed for Profile Button
 

Wikipedia/Code/SearchViewController.swift

@@ -3,7 +3,7 @@ import WMFComponents
 import WMFData
 import CocoaLumberjackSwift
 
-class SearchViewController: ArticleCollectionViewController, WMFNavigationBarConfiguring, WMFNavigationBarHiding {
+class SearchViewController: ArticleCollectionViewController, WMFNavigationBarConfiguring {
 
     @objc enum EventLoggingSource: Int {
         case searchTab
@@ -37,9 +37,6 @@ class SearchViewController: ArticleCollectionViewController, WMFNavigationBarCon
     private var searchLanguageBarViewController: SearchLanguagesBarViewController?
     private var needsAnimateLanguageBarMovement = false
 
-    var topSafeAreaOverlayView: UIView?
-    var topSafeAreaOverlayHeightConstraint: NSLayoutConstraint?
-
     // Properties needed for Profile Button
 
     private var _yirCoordinator: YearInReviewCoordinator?