Add haptic feedback to cell selection

Reader/Screens/Home/HomeViewController.swift

@@ -214,6 +214,7 @@ extension HomeViewController: UICollectionViewDelegate {
         let vc = ItemsViewController(fetchRequest: item.fetchRequest, fervorController: fervorController)
         vc.title = item.title
         show(vc, sender: nil)
+        UISelectionFeedbackGenerator().selectionChanged()
     }
     
     func collectionView(_ collectionView: UICollectionView, contextMenuConfigurationForItemAt indexPath: IndexPath, point: CGPoint) -> UIContextMenuConfiguration? {

Reader/Screens/Items/ItemCollectionViewCell.swift

@@ -19,10 +19,12 @@ class ItemCollectionViewCell: UICollectionViewListCell {
     private let titleLabel = UILabel()
     private let feedTitleLabel = UILabel()
     private let contentLabel = UILabel()
-    private var shouldHighlight = true
+    private var shouldInteractOnNextTouch = true
     
     private var item: Item!
     
+    private lazy var feedbackGenerator = UISelectionFeedbackGenerator()
+    
     override init(frame: CGRect) {
         super.init(frame: frame)
         
@@ -55,7 +57,7 @@ class ItemCollectionViewCell: UICollectionViewListCell {
         ])
         
         let doubleTap = DoubleTapRecognizer(target: self, action: #selector(cellDoubleTapped))
-        doubleTap.onTouchesBegan = highlightCell
+        doubleTap.onTouchesBegan = onDoubleTapBegan
         addGestureRecognizer(doubleTap)
         
         let singleTap = UITapGestureRecognizer(target: self, action: #selector(cellSingleTapped))
@@ -108,13 +110,10 @@ class ItemCollectionViewCell: UICollectionViewListCell {
         }
     }
     
-    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
-        highlightCell()
-    }
-    
-    @objc private func highlightCell() {
-        guard shouldHighlight else { return }
-        shouldHighlight = false
+    private func onDoubleTapBegan() {
+        guard shouldInteractOnNextTouch else { return }
+        shouldInteractOnNextTouch = false
+        feedbackGenerator.prepare()
         UIView.animateKeyframes(withDuration: 0.4, delay: 0, options: .allowUserInteraction) {
             UIView.addKeyframe(withRelativeStartTime: 0, relativeDuration: 0.5) {
                 self.backgroundColor = .appCellHighlightBackground
@@ -127,12 +126,14 @@ class ItemCollectionViewCell: UICollectionViewListCell {
     
     @objc private func cellDoubleTapped() {
         setRead(!item.read, animated: true)
-        shouldHighlight = true
+        shouldInteractOnNextTouch = true
+        feedbackGenerator.selectionChanged()
     }
     
     @objc private func cellSingleTapped() {
         delegate?.itemCellSelected(cell: self, item: item)
-        shouldHighlight = true
+        shouldInteractOnNextTouch = true
+        feedbackGenerator.selectionChanged()
     }
 
 }
@@ -149,5 +150,12 @@ private class DoubleTapRecognizer: UITapGestureRecognizer {
     override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent) {
         super.touchesBegan(touches, with: event)
         onTouchesBegan()
+        // shorten the delay before the single tap is recognized
+        DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(300)) { [weak self] in
+            guard let self = self else { return }
+            if self.state != .recognized {
+                self.state = .failed
+            }
+        }
     }
 }