optimize collection view empty data set

Author: hongxinhope

Example/EmptyDataDemoCollectionViewController.swift

@@ -73,8 +73,9 @@ class EmptyDataDemoCollectionViewController: UICollectionViewController, TBEmpty
         self.dataCount -= 1
         collectionView.performBatchUpdates({
             self.collectionView?.deleteItemsAtIndexPaths([indexPath])
-            }) { (finished) in
-                self.collectionView?.updateEmptyDataSetIfNeeded()
+            }) { (completed) in
+                print("completed successfully: \(completed)")
+//                self.collectionView?.updateEmptyDataSetIfNeeded()
         }
     }
 

Example/Info.plist

@@ -15,11 +15,11 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.9</string>
+	<string>2.0</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>10</string>
+	<string>11</string>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>UILaunchStoryboardName</key>

TBEmptyDataSet/Constants.swift

@@ -8,6 +8,7 @@
 
 import UIKit
 
+// swiftlint:disable variable_name
 struct AssociatedKeys {
     static var emptyDataSetDataSource = "emptyDataSetDataSource"
     static var emptyDataSetDelegate = "emptyDataSetDelegate"
@@ -18,6 +19,7 @@ struct Selectors {
     static let tableViewSwizzledReloadData = #selector(UIScrollView.tb_tableViewSwizzledReloadData)
     static let tableViewSwizzledEndUpdates = #selector(UIScrollView.tb_tableViewSwizzledEndUpdates)
     static let collectionViewSwizzledReloadData = #selector(UIScrollView.tb_collectionViewSwizzledReloadData)
+    static let collectionViewSwizzledPerformBatchUpdates = #selector(UIScrollView.tb_collectionViewSwizzledPerformBatchUpdates(_:completion:))
 }
 
 struct TableViewSelectors {
@@ -29,6 +31,7 @@ struct TableViewSelectors {
 struct CollectionViewSelectors {
     static let reloadData = #selector(UICollectionView.reloadData)
     static let numberOfSections = #selector(UICollectionViewDataSource.numberOfSectionsInCollectionView(_:))
+    static let performBatchUpdates = #selector(UICollectionView.performBatchUpdates(_:completion:))
 }
 
 struct DefaultValues {

TBEmptyDataSet/Supporting Files/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.9</string>
+	<string>2.0</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>

TBEmptyDataSet/TBEmptyDataSet.swift

@@ -53,6 +53,7 @@ extension UIScrollView: UIGestureRecognizerDelegate {
                 }
                 if self is UICollectionView {
                     UICollectionView.tb_swizzleCollectionViewReloadData()
+                    UICollectionView.tb_swizzleCollectionViewPerformBatchUpdates()
                 }
             } else {
                 handlingInvalidEmptyDataSet()
@@ -347,6 +348,19 @@ extension UIScrollView: UIGestureRecognizerDelegate {
         }
     }
 
+    private class func tb_swizzleCollectionViewPerformBatchUpdates() {
+        struct EmptyDataSetSwizzleToken {
+            static var onceToken: dispatch_once_t = 0
+        }
+        dispatch_once(&EmptyDataSetSwizzleToken.onceToken) {
+            let originalSelector = CollectionViewSelectors.performBatchUpdates
+            let swizzledSelector = Selectors.collectionViewSwizzledPerformBatchUpdates
+
+            tb_swizzleMethod(originalSelector, swizzledSelector: swizzledSelector)
+            print(#function)
+        }
+    }
+
     func tb_tableViewSwizzledReloadData() {
         tb_tableViewSwizzledReloadData()
         reloadEmptyDataSet()
@@ -361,4 +375,11 @@ extension UIScrollView: UIGestureRecognizerDelegate {
         tb_collectionViewSwizzledReloadData()
         reloadEmptyDataSet()
     }
+
+    func tb_collectionViewSwizzledPerformBatchUpdates(updates: (() -> Void)?, completion: ((Bool) -> Void)?) {
+        tb_collectionViewSwizzledPerformBatchUpdates(updates) { [weak self](completed) in
+            completion?(completed)
+            self?.reloadEmptyDataSet()
+        }
+    }
 }