Show selected filter in the Discover navigation bar (#23956)

Author: kean

RELEASE-NOTES.txt

@@ -16,6 +16,7 @@
 * [*] Update site menu style on iPhone [#23944]
 * [*] Integrate zoom transitions in Themes, Reader [#23945, #23947]
 * [*] Fix an issue with site icons cropped in share extensions [#23950]
+* [*] Show selected filter in the Discover navigation bar [#23956]
 * [*] Enable fast deceleration for filters on the Discover tab [#23954]
 * [*] Disable universal links support for QR code login. You can only scan the codes using the app now. [#23953]
 

WordPress/Classes/ViewRelated/Reader/Controllers/ReaderDiscoverViewController.swift

@@ -127,7 +127,10 @@ class ReaderDiscoverViewController: UIViewController, ReaderDiscoverHeaderViewDe
         streamVC.view.pinEdges()
         streamVC.didMove(toParent: self)
 
-        navigationItem.titleView = streamVC.navigationItem.titleView // important
+        streamVC.titleView.detailsLabel.text = selectedChannel.localizedTitle
+        streamVC.titleView.detailsLabel.isHidden = false
+
+        navigationItem.titleView = streamVC.titleView // important
     }
 
     /// TODO: (tech-debt) the app currently stores the responses from the `/discover`

WordPress/Classes/ViewRelated/Reader/Controllers/ReaderStreamViewController.swift

@@ -65,8 +65,9 @@ import AutomatticTracks
         return refreshControl
     }()
 
-    private let loadMoreThreashold = 4
+    let titleView = ReaderNavigationCustomTitleView()
 
+    private let loadMoreThreashold = 5
     private let refreshInterval = 300
     private var cleanupAndRefreshAfterScrolling = false
     private let recentlyBlockedSitePostObjectIDs = NSMutableArray()
@@ -77,7 +78,6 @@ import AutomatticTracks
     private var indexPathForGapMarker: IndexPath?
     private var didSetupView = false
     private var didBumpStats = false
-    @Lazy private var titleView = ReaderNavigationCustomTitleView()
     internal let scrollViewTranslationPublisher = PassthroughSubject<Bool, Never>()
     private let notificationsButtonViewModel = NotificationsButtonViewModel()
     private var notificationsButtonCancellable: AnyCancellable?
@@ -1660,7 +1660,7 @@ extension ReaderStreamViewController: UITableViewDelegate, JPScrollViewDelegate
     func scrollViewDidScroll(_ scrollView: UIScrollView) {
         layoutEmptyStateView()
         processJetpackBannerVisibility(scrollView)
-        $titleView.value?.updateAlpha(in: scrollView)
+        titleView.updateAlpha(in: scrollView)
     }
 }
 

WordPress/Classes/ViewRelated/Reader/ReaderNavigationCustomTitleView.swift

@@ -4,31 +4,36 @@ import WordPressUI
 /// A custom replacement for a navigation bar title view.
 final class ReaderNavigationCustomTitleView: UIView {
     let textLabel = UILabel()
+    let detailsLabel = UILabel()
+    private lazy var stackView = UIStackView(axis: .vertical, alignment: .center, [textLabel, detailsLabel])
 
     override init(frame: CGRect) {
         super.init(frame: frame)
 
         textLabel.font = WPStyleGuide.navigationBarStandardFont
-        textLabel.alpha = 0
 
-        // The label has to be a subview of the title view because
-        // navigation bar doesn't seem to allow you to change the alpha
-        // of `navigationItem.titleView` itself.
-        addSubview(textLabel)
-        textLabel.pinEdges()
+        detailsLabel.font = .preferredFont(forTextStyle: .footnote)
+        detailsLabel.textColor = .secondaryLabel
+        detailsLabel.isHidden = true
+
+        addSubview(stackView)
+        stackView.pinEdges()
     }
 
     required init?(coder: NSCoder) {
         fatalError("init(coder:) has not been implemented")
     }
 
+    // The label has to be a subview of the title view because
+    // navigation bar doesn't seem to allow you to change the alpha
+    // of `navigationItem.titleView` itself.
     func updateAlpha(in scrollView: UIScrollView) {
         let offsetY = scrollView.contentOffset.y
         if offsetY < 16 {
-            textLabel.alpha = 0
+            stackView.alpha = 0
         } else {
             let alpha = (offsetY - 16) / 24
-            textLabel.alpha = max(0, min(1, alpha))
+            stackView.alpha = max(0, min(1, alpha))
         }
     }
 }