Multiple selection gesture YAY!

Author: shaps80

Sources/ComposedMediaUI/MediaAssetCell.swift

@@ -12,6 +12,25 @@ final class MediaAssetCell: UICollectionViewCell {
         return view
     }()
 
+    private(set) lazy var selectionImageView: UIImageView = {
+        let view = UIImageView()
+        view.backgroundColor = .clear
+        view.translatesAutoresizingMaskIntoConstraints = false
+        view.clipsToBounds = true
+        view.contentMode = .scaleAspectFit
+        view.adjustsImageSizeForAccessibilityContentSizeCategory = true
+
+        if #available(iOS 13.0, *) {
+            let config = UIImage.SymbolConfiguration(pointSize: 20, weight: .medium, scale: .medium)
+            view.preferredSymbolConfiguration = config
+            view.tintColor = .label
+        } else {
+            view.tintColor = .white
+        }
+
+        return view
+    }()
+
     private(set) weak var asset: PHAsset?
     private(set) var onReuse: (() -> Void)?
 
@@ -37,11 +56,26 @@ final class MediaAssetCell: UICollectionViewCell {
         t.duration = 0.1
         imageView.layer.add(t, forKey: nil)
         imageView.alpha = isEditing && selected ? 0.5 : 1
+
+        guard isEditing else { return }
+
+        if #available(iOS 13.0, *) {
+            selectionImageView.image = selected
+                ? UIImage(systemName: "checkmark.circle.fill")
+                : nil
+        } else {
+            // ✓
+//            selectionImageView.image = selected
+//            ? UIImage(systemName: "circle.fill")
+//            : nil
+        }
     }
 
     private func prepare() {
         contentView.layoutMargins = .zero
+
         contentView.addSubview(imageView)
+        contentView.addSubview(selectionImageView)
 
         NSLayoutConstraint.activate([
             imageView.topAnchor.constraint(lessThanOrEqualTo: contentView.layoutMarginsGuide.topAnchor),
@@ -50,6 +84,9 @@ final class MediaAssetCell: UICollectionViewCell {
             imageView.bottomAnchor.constraint(lessThanOrEqualTo: contentView.layoutMarginsGuide.bottomAnchor),
             imageView.centerXAnchor.constraint(equalTo: contentView.layoutMarginsGuide.centerXAnchor),
             imageView.centerYAnchor.constraint(equalTo: contentView.layoutMarginsGuide.centerYAnchor),
+
+            selectionImageView.trailingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: -10),
+            selectionImageView.bottomAnchor.constraint(equalTo: imageView.bottomAnchor, constant: -10)
         ])
     }
 

Sources/ComposedMediaUI/MediaAssetSection.swift

@@ -51,7 +51,7 @@ extension MediaAssetSection {
 extension MediaAssetSection: CollectionSectionProvider {
 
     public func section(with traitCollection: UITraitCollection) -> CollectionSection {
-        let cell = CollectionCellElement(section: self, dequeueMethod: .fromClass(MediaAssetCell.self)) { cell, index, section in
+        let cell = CollectionCellElement(section: self, dequeueMethod: .fromClass(MediaAssetCell.self), configure: { cell, index, section in
             let config = section.configuration
             let asset = section.element(at: index)
 
@@ -63,10 +63,10 @@ extension MediaAssetSection: CollectionSectionProvider {
                 }
             }
 
-            cell.prepareAsset(asset) {
+            cell.prepareAsset(asset, onReuse: {
                 section.imageManager.cancelImageRequest(imageRequestId)
-            }
-        }
+            })
+        })
 
         return CollectionSection(section: self, cell: cell)
     }
@@ -153,10 +153,6 @@ extension MediaAssetSection: CollectionSelectionHandler {
 
 extension MediaAssetSection: CollectionEditingHandler {
 
-    public func allowsEditing(at index: Int) -> Bool {
-        return index != 0
-    }
-
     public func setEditing(_ editing: Bool) {
         allowsMultipleSelection = editing
     }

Sources/ComposedMediaUI/MediaViewController.swift

@@ -93,7 +93,6 @@ open class MediaViewController: UIViewController {
 
         collectionCoordinator?.setEditing(editing, animated: animated)
         updateNavigationItems(editing: editing, animated: animated)
-        navigationController?.setToolbarHidden(!editing, animated: animated)
     }
 
     @objc private func open(_ sender: Any?) {
@@ -131,7 +130,11 @@ open class MediaViewController: UIViewController {
             navigationItem.rightBarButtonItems?.last?.isEnabled = collectionView.indexPathsForSelectedItems?.isEmpty == false
         }
 
-        navigationItem.title = editing ? "Select Items" : title
+        navigationItem.title = editing
+            ? collectionView.indexPathsForSelectedItems?.isEmpty == true
+                ? NSLocalizedString("Select Items", comment: "")
+                : "\(collectionView.indexPathsForSelectedItems?.count ?? 0) \(NSLocalizedString("Selected", comment: ""))"
+            : title
     }
 
     @objc private func performSelectAll(_ sender: Any?) {
@@ -152,7 +155,6 @@ open class MediaViewController: UIViewController {
 
     open override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
         super.viewWillTransition(to: size, with: coordinator)
-        imageManager.stopCachingImagesForAllAssets()
 
         if layout is UICollectionViewFlowLayout {
             collectionCoordinator?.invalidateLayout()
@@ -168,6 +170,10 @@ open class MediaViewController: UIViewController {
 
 extension MediaViewController: UICollectionViewDelegate {
 
+    public func collectionView(_ collectionView: UICollectionView, shouldBeginMultipleSelectionInteractionAt indexPath: IndexPath) -> Bool {
+        return false
+    }
+
     public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
         updateNavigationItems(editing: isEditing, animated: false)
     }