Add scroll-to-top button to Reader streams (#23957)

RELEASE-NOTES.txt

@@ -19,6 +19,8 @@
 * [*] 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]
+* [*] Add scroll-to-top button to Reader streams [#23957]
+
 
 25.6
 -----

WordPress/Classes/Utility/Analytics/WPAnalyticsEvent.swift

@@ -5,7 +5,6 @@ import Foundation
 
     case createSheetShown
     case createSheetActionTapped
-    case createAnnouncementModalShown
 
     // Media Editor
     case mediaEditorShown
@@ -117,6 +116,7 @@ import Foundation
     case readerCommentTextCopied
     case readerPostContextMenuButtonTapped
     case readerAddSiteToFavoritesTapped
+    case readerButtonScrollToTopTapped
 
     // Stats - Empty Stats nudges
     case statsPublicizeNudgeShown
@@ -625,8 +625,6 @@ import Foundation
             return "create_sheet_shown"
         case .createSheetActionTapped:
             return "create_sheet_action_tapped"
-        case .createAnnouncementModalShown:
-            return "create_announcement_modal_shown"
         // Media Editor
         case .mediaEditorShown:
             return "media_editor_shown"
@@ -819,6 +817,8 @@ import Foundation
             return "reader_post_context_menu_button_tapped"
         case .readerAddSiteToFavoritesTapped:
             return "reader_add_site_to_favorites_tapped"
+        case .readerButtonScrollToTopTapped:
+            return "reader_button_scroll_to_top_tapped"
 
         // Stats - Empty Stats nudges
         case .statsPublicizeNudgeShown:

WordPress/Classes/ViewRelated/Reader/Cards/ReaderPostCell.swift

@@ -168,7 +168,7 @@ private final class ReaderPostCellView: UIView {
             avatarView.widthAnchor.constraint(equalToConstant: ReaderPostCell.avatarSize),
             avatarView.heightAnchor.constraint(equalToConstant: ReaderPostCell.avatarSize),
             avatarView.centerYAnchor.constraint(equalTo: timeLabel.centerYAnchor),
-            avatarView.trailingAnchor.constraint(equalTo: headerView.leadingAnchor, constant: -8),
+            avatarView.trailingAnchor.constraint(equalTo: headerView.leadingAnchor, constant: -9),
 
             headerView.topAnchor.constraint(equalTo: topAnchor, constant: 6),
             headerView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: insets.left),

WordPress/Classes/ViewRelated/Reader/Cards/ReaderStreamBaseCell.swift

@@ -1,7 +1,7 @@
 import UIKit
 
 class ReaderStreamBaseCell: UITableViewCell {
-    static let insets = UIEdgeInsets(top: 0, left: 44, bottom: 0, right: 16)
+    static let insets = UIEdgeInsets(top: 0, left: 46, bottom: 0, right: 16)
 
     var isCompact: Bool = true {
         didSet {

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

@@ -65,13 +65,16 @@ import AutomatticTracks
         return refreshControl
     }()
 
+    private lazy var buttonScrollToTop = ReaderButtonScrollToTop.make { [weak self] in
+        self?.tableView.scrollToTop(animated: true)
+    }
+
     let titleView = ReaderNavigationCustomTitleView()
 
     private let loadMoreThreashold = 5
     private let refreshInterval = 300
     private var cleanupAndRefreshAfterScrolling = false
     private let recentlyBlockedSitePostObjectIDs = NSMutableArray()
-    private let heightForFooterView = CGFloat(44)
     private let estimatedHeightsCache = NSCache<AnyObject, AnyObject>()
     private var isFeed = false
     private var syncIsFillingGap = false
@@ -303,6 +306,7 @@ import AutomatticTracks
         setupTableView()
         setupFooterView()
         setupContentHandler()
+        setupButtonScrollToTop()
 
         observeNetworkStatus()
 
@@ -493,9 +497,14 @@ import AutomatticTracks
         content.initializeContent(tableView: tableView, delegate: self)
     }
 
+    private func setupButtonScrollToTop() {
+        view.addSubview(buttonScrollToTop)
+        buttonScrollToTop.pinEdges([.leading, .bottom], to: view.safeAreaLayoutGuide, insets: isCompact ? UIEdgeInsets(horizontal: 8, vertical: 16) : UIEdgeInsets(.all, 20))
+    }
+
     private func setupFooterView() {
         var frame = footerView.frame
-        frame.size.height = heightForFooterView
+        frame.size.height = 44
         footerView.frame = frame
         tableView.tableFooterView = footerView
         footerView.isHidden = true
@@ -1661,6 +1670,7 @@ extension ReaderStreamViewController: UITableViewDelegate, JPScrollViewDelegate
         layoutEmptyStateView()
         processJetpackBannerVisibility(scrollView)
         titleView.updateAlpha(in: scrollView)
+        buttonScrollToTop.setButtonHidden(scrollView.contentOffset.y < view.bounds.height / 3, animated: true)
     }
 }
 

WordPress/Classes/ViewRelated/Reader/ReaderButtonScrollToTop.swift

@@ -0,0 +1,34 @@
+import UIKit
+
+final class ReaderButtonScrollToTop: UIButton {
+    private var isButtonHidden = false
+
+    static func make(closure: @escaping () -> Void) -> ReaderButtonScrollToTop {
+        var configuration = UIButton.Configuration.bordered()
+        configuration.image = UIImage(systemName: "arrow.up")?
+                .withConfiguration(UIImage.SymbolConfiguration(pointSize: 12, weight: .regular))
+        configuration.cornerStyle = .capsule
+        configuration.baseBackgroundColor = .secondarySystemBackground
+        configuration.baseForegroundColor = .label
+        configuration.contentInsets = .init(top: 10, leading: 10, bottom: 10, trailing: 10)
+
+        return ReaderButtonScrollToTop(configuration: configuration, primaryAction: .init { _ in
+            closure()
+            WPAnalytics.track(.readerButtonScrollToTopTapped)
+        })
+    }
+
+    func setButtonHidden(_ isHidden: Bool, animated: Bool) {
+        guard isButtonHidden != isHidden else { return }
+        isButtonHidden = isHidden
+
+        UIView.animate(withDuration: animated ? 0.33 : 0.0) {
+            self.alpha = isHidden ? 0 : 1
+            self.isUserInteractionEnabled = !isHidden
+        }
+    }
+
+    override func point(inside point: CGPoint, with event: UIEvent?) -> Bool {
+        bounds.insetBy(dx: -8, dy: -10).contains(point)
+    }
+}