From d453a9433089acbc09d76375fea38f44444d0c0d Mon Sep 17 00:00:00 2001
From: Maurice Parker <mo@vincode.io>
Date: Thu, 18 Jun 2020 17:37:29 -0500
Subject: [PATCH] Make unread and star animations cancel on cell reuse.  Issue
 #2054

---
 .../Cell/MasterTimelineTableViewCell.swift    | 30 +++++++++++++++----
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/iOS/MasterTimeline/Cell/MasterTimelineTableViewCell.swift b/iOS/MasterTimeline/Cell/MasterTimelineTableViewCell.swift
index aa964b218..55183f29b 100644
--- a/iOS/MasterTimeline/Cell/MasterTimelineTableViewCell.swift
+++ b/iOS/MasterTimeline/Cell/MasterTimelineTableViewCell.swift
@@ -23,6 +23,9 @@ class MasterTimelineTableViewCell: VibrantTableViewCell {
 		return NonIntrinsicImageView(image: AppAssets.timelineStarImage)
 	}()
 	
+	private var unreadIndicatorPropertyAnimator: UIViewPropertyAnimator?
+	private var starViewPropertyAnimator: UIViewPropertyAnimator?
+
 	var cellData: MasterTimelineCellData! {
 		didSet {
 			updateSubviews()
@@ -35,7 +38,12 @@ class MasterTimelineTableViewCell: VibrantTableViewCell {
 	}
 	
 	override func prepareForReuse() {
+		unreadIndicatorPropertyAnimator?.stopAnimation(true)
+		unreadIndicatorPropertyAnimator = nil
 		unreadIndicatorView.isHidden = true
+
+		starViewPropertyAnimator?.stopAnimation(true)
+		starViewPropertyAnimator = nil
 		starView.isHidden = true
 	}
 	
@@ -184,10 +192,15 @@ private extension MasterTimelineTableViewCell {
 	
 	func updateUnreadIndicator() {
 		if !unreadIndicatorView.isHidden && cellData.read && !cellData.starred {
-			UIView.animate(withDuration: 0.66, animations: { self.unreadIndicatorView.alpha = 0 }) { _ in
-				self.unreadIndicatorView.isHidden = true
-				self.unreadIndicatorView.alpha = 1
+			unreadIndicatorPropertyAnimator = UIViewPropertyAnimator(duration: 0.66, curve: .easeInOut) { [weak self] in
+				self?.unreadIndicatorView.alpha = 0
 			}
+			unreadIndicatorPropertyAnimator?.addCompletion { [weak self] _ in
+				self?.unreadIndicatorView.isHidden = true
+				self?.unreadIndicatorView.alpha = 1
+				self?.unreadIndicatorPropertyAnimator = nil
+			}
+			unreadIndicatorPropertyAnimator?.startAnimation()
 		} else {
 			showOrHideView(unreadIndicatorView, cellData.read || cellData.starred)
 		}
@@ -195,10 +208,15 @@ private extension MasterTimelineTableViewCell {
 	
 	func updateStarView() {
 		if !starView.isHidden &&  cellData.read && !cellData.starred {
-			UIView.animate(withDuration: 0.66, animations: { self.starView.alpha = 0 }) { _ in
-				self.starView.isHidden = true
-				self.starView.alpha = 1
+			starViewPropertyAnimator = UIViewPropertyAnimator(duration: 0.66, curve: .easeInOut) { [weak self] in
+				self?.starView.alpha = 0
 			}
+			starViewPropertyAnimator?.addCompletion { [weak self] _ in
+				self?.starView.isHidden = true
+				self?.starView.alpha = 1
+				self?.starViewPropertyAnimator = nil
+			}
+			starViewPropertyAnimator?.startAnimation()
 		} else {
 			showOrHideView(starView, !cellData.starred)
 		}