Performance improvement with cell reuse

.swift-version

@@ -1 +1 @@
-4.0
+4.2

.travis.yml

@@ -1,8 +1,11 @@
 language: swift
-osx_image: xcode9.4
+osx_image: xcode10
 
 script: 
-  xcodebuild -workspace CollectionKit.xcworkspace -scheme CollectionKit -sdk iphonesimulator -destination 'platform=iOS Simulator,name=iPhone 7,OS=10.3.1' build test
+  xcodebuild -workspace CollectionKit.xcworkspace -scheme CollectionKit -sdk iphonesimulator -destination 'platform=iOS Simulator,name=iPhone XR,OS=12.0' build test
+
+before_install:
+  - pod repo update
 
 after_success:
   - bash <(curl -s https://codecov.io/bash) -J 'CollectionKit'

CollectionKit.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = "CollectionKit"
-  s.version          = "2.1.0"
+  s.version          = "2.2.0"
   s.summary          = "A modern swift framework for building data-driven reusable collection view components."
 
   s.description      = <<-DESC
@@ -39,7 +39,7 @@ Pod::Spec.new do |s|
 
   s.subspec 'WobbleAnimator' do |cs|
     cs.dependency 'CollectionKit/Core'
-    cs.dependency 'YetAnotherAnimationLibrary'
+    cs.dependency 'YetAnotherAnimationLibrary', "~> 1.3.0"
     cs.source_files = 'WobbleAnimator/**/*.swift'
   end
 end

Podfile

@@ -3,6 +3,6 @@ use_frameworks!
 
 target "CollectionKitTests" do
 
-	pod 'Quick', "= 1.3.0"
-	pod 'Nimble', "= 7.1.1"
+	pod 'Quick', "= 1.3.2"
+	pod 'Nimble', "= 7.3.1"
 end

Podfile.lock

@@ -1,20 +1,20 @@
 PODS:
-  - Nimble (7.1.1)
-  - Quick (1.3.0)
+  - Nimble (7.3.1)
+  - Quick (1.3.2)
 
 DEPENDENCIES:
-  - Nimble (= 7.1.1)
-  - Quick (= 1.3.0)
+  - Nimble (= 7.3.1)
+  - Quick (= 1.3.2)
 
 SPEC REPOS:
   https://github.com/cocoapods/specs.git:
     - Nimble
     - Quick
 
 SPEC CHECKSUMS:
-  Nimble: 391f07782af4b37914f9bd7b2ffbb952731b8202
-  Quick: 03278013f71aa05fe9ecabc94fbcc6835f1ee76f
+  Nimble: 04f732da099ea4d153122aec8c2a88fd0c7219ae
+  Quick: 2623cb30d7a7f41ca62f684f679586558f483d46
 
-PODFILE CHECKSUM: f33c8746ebf721eac77bc6829bdd94f9e3b0de44
+PODFILE CHECKSUM: 056648a7e76b878641ac9a9fd2b13117bd03b5db
 
 COCOAPODS: 1.5.3

Sources/Extensions/UIView+CollectionKit.swift

@@ -37,7 +37,10 @@ extension UIView {
   }
 
   public func recycleForCollectionKitReuse() {
-    removeFromSuperview()
-    reuseManager?.queue(view: self)
+    if let reuseManager = reuseManager {
+      reuseManager.queue(view: self)
+    } else {
+      removeFromSuperview()
+    }
   }
 }

Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.1.0</string>
+	<string>2.2.0</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>NSPrincipalClass</key>

Sources/Other/CollectionReuseViewManager.swift

@@ -13,21 +13,39 @@ public protocol CollectionViewReusableView: class {
 }
 
 public class CollectionReuseViewManager: NSObject {
+
+  /// Time it takes for CollectionReuseViewManager to
+  /// dump all reusableViews to save memory
+  public var lifeSpan: TimeInterval = 5.0
+
+  /// When `removeFromCollectionViewWhenReuse` is enabled,
+  /// cells will always be removed from Collection View during reuse.
+  /// This is slower but it doesn't influence the `isHidden` property
+  /// of individual cells.
+  public var removeFromCollectionViewWhenReuse = false
+
   var reusableViews: [String: [UIView]] = [:]
   var cleanupTimer: Timer?
-  public var lifeSpan: TimeInterval = 0.5
 
   public func queue(view: UIView) {
     let identifier = NSStringFromClass(type(of: view))
     view.reuseManager = nil
+    if removeFromCollectionViewWhenReuse {
+      view.removeFromSuperview()
+    } else {
+      view.isHidden = true
+    }
     if reusableViews[identifier] != nil && !reusableViews[identifier]!.contains(view) {
       reusableViews[identifier]?.append(view)
     } else {
       reusableViews[identifier] = [view]
     }
-    cleanupTimer?.invalidate()
-    cleanupTimer = Timer.scheduledTimer(timeInterval: lifeSpan, target: self,
-                                        selector: #selector(cleanup), userInfo: nil, repeats: false)
+    if let cleanupTimer = cleanupTimer {
+      cleanupTimer.fireDate = Date().addingTimeInterval(lifeSpan)
+    } else {
+      cleanupTimer = Timer.scheduledTimer(timeInterval: lifeSpan, target: self,
+                                          selector: #selector(cleanup), userInfo: nil, repeats: false)
+    }
   }
 
   public func dequeue<T: UIView> (_ defaultView: @autoclosure () -> T) -> T {
@@ -37,22 +55,25 @@ public class CollectionReuseViewManager: NSObject {
     if let view = view as? CollectionViewReusableView {
       view.prepareForReuse()
     }
+    if !removeFromCollectionViewWhenReuse {
+      view.isHidden = false
+    }
     view.reuseManager = self
     return view
   }
 
   public func dequeue<T: UIView> (type: T.Type) -> T {
-    let identifier = NSStringFromClass(type.self)
-    let queuedView = reusableViews[identifier]?.popLast() as? T
-    let view = queuedView ?? type.init()
-    if let view = view as? CollectionViewReusableView {
-        view.prepareForReuse()
-    }
-    view.reuseManager = self
-    return view
+    return dequeue(type.init())
   }
 
   @objc func cleanup() {
+    for views in reusableViews.values {
+      for view in views {
+        view.removeFromSuperview()
+      }
+    }
     reusableViews.removeAll()
+    cleanupTimer?.invalidate()
+    cleanupTimer = nil
   }
 }