Fix for IOS15 behaviour. Merge pull request #25 from ekazaev/feature/fix_ios15

Fix for IOS15 behaviour

Author: ekazaev

.gitignore

@@ -89,3 +89,4 @@ fastlane/test_output
 
 iOSInjectionProject/
 Example/Pods
+Gemfile.lock

ChatLayout.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = 'ChatLayout'
-  s.version          = '1.1.9'
+  s.version          = '1.1.10'
   s.summary          = 'Chat UI Library. It uses custom UICollectionViewLayout to provide you full control over the presentation.'
   s.swift_version    = '5.2'
 

ChatLayout/Classes/Core/ChatLayout.swift

@@ -101,7 +101,14 @@ public final class ChatLayout: UICollectionViewLayout {
 
     /// The width and height of the collection view’s contents.
     public override var collectionViewContentSize: CGSize {
-        let contentSize = controller.contentSize(for: .beforeUpdate)
+        let contentSize: CGSize
+        if state == .beforeUpdate {
+            contentSize = controller.contentSize(for: .beforeUpdate)
+        } else {
+            var size = controller.contentSize(for: .beforeUpdate)
+            size.height += controller.totalProposedCompensatingOffset
+            contentSize = size
+        }
         return contentSize
     }
 
@@ -637,10 +644,6 @@ public final class ChatLayout: UICollectionViewLayout {
             controller.batchUpdateCompensatingOffset = 0
             let context = ChatLayoutInvalidationContext()
             context.contentOffsetAdjustment.y = compensatingOffset
-            if !isIOS15orHigher {
-                let contentHeightAdjustment: CGFloat = controller.contentSize(for: .afterUpdate).height - controller.contentSize(for: .beforeUpdate).height
-                context.contentSizeAdjustment.height = contentHeightAdjustment
-            }
             invalidateLayout(with: context)
         } else {
             controller.batchUpdateCompensatingOffset = 0
@@ -946,12 +949,3 @@ var isIOS13orHigher: Bool {
         return false
     }
 }
-
-@inline(__always)
-var isIOS15orHigher: Bool {
-    if #available(iOS 15.0, *) {
-        return true
-    } else {
-        return false
-    }
-}

Example/ChatLayout/Chat/View/ChatViewController.swift

@@ -29,12 +29,12 @@ final class ChatViewController: UIViewController {
         case scrollingToBottom
         case showingPreview
         case showingAccessory
-        case updatingCollection
     }
 
     private enum ControllerActions {
         case loadingInitialMessages
         case loadingPreviousMessages
+        case updatingCollection
     }
 
     override var inputAccessoryView: UIView? {
@@ -377,7 +377,7 @@ extension ChatViewController: UICollectionViewDelegate {
     @available(iOS 13.0, *)
     func collectionView(_ collectionView: UICollectionView, contextMenuConfigurationForItemAt indexPath: IndexPath, point: CGPoint) -> UIContextMenuConfiguration? {
         guard !currentInterfaceActions.options.contains(.showingPreview),
-              !currentInterfaceActions.options.contains(.updatingCollection) else {
+              !currentControllerActions.options.contains(.updatingCollection) else {
             return nil
         }
         let item = dataSource.sections[indexPath.section].cells[indexPath.item]
@@ -442,9 +442,7 @@ extension ChatViewController: ChatControllerDelegate {
             // Here is on the main thread for the simplicity.
             let changeSet = StagedChangeset(source: dataSource.sections, target: sections).flattenIfPossible()
 
-            // In IOS 15 Apple as usual broke something in the UICollectionViewLayout and if simultaneous updates happen when the previous animation is not finished,
-            // it doesnt caclulate content offset correctly. So we are blocking processing changes whilest the previoues batch update is in progress.
-            currentInterfaceActions.options.insert(.updatingCollection)
+            currentControllerActions.options.insert(.updatingCollection)
 
             collectionView.reload(using: changeSet,
                                   interrupt: { changeSet in
@@ -462,7 +460,7 @@ extension ChatViewController: ChatControllerDelegate {
                                   completion: { _ in
                                       DispatchQueue.main.async {
                                           completion?()
-                                          self.currentInterfaceActions.options.remove(.updatingCollection)
+                                          self.currentControllerActions.options.remove(.updatingCollection)
                                       }
                                   },
                                   setData: { data in

Example/Podfile.lock

@@ -42,4 +42,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 8c714139f0a07a1f2169fe35aa2829ae446d122a
 
-COCOAPODS: 1.10.1
+COCOAPODS: 1.11.2

Gemfile

@@ -1,4 +1,5 @@
 source "https://rubygems.org"
 
 gem "slather", "2.6.1"
-gem "cocoapods"
+gem "cocoapods"
+gem "jazzy"

Gemfile.lock

@@ -33,7 +33,6 @@
     - [About Supplementary Views](#about-supplementary-views)
     - [About Texture](#about-texture)
     - [About animation](#about-animation)
-    - [About IOS 15 Beta](#about-ios-15-beta)
 - [License](#license)
 - [Articles](#articles)
 - [Author](#author)
@@ -148,12 +147,6 @@ It is very possible that you are sending delete/insert commands when you expect
 `print("\(updateItems)")` into `ChatLayout.prepare(forCollectionViewUpdates:)` method. `ChatLayout` doesn't know what you expected to see. 
 It just processes your changes according to the commands it has received.
 
-### About IOS 15 Beta
-
-It seems that in the latest release of IOS 15 it is impossible to call `UICollectionView`'s `performBatchUpdates` while 
-another is still processing animation and keep the content offset in the correct place. Please check to the Example 
-app `ChatViewController` how to avoid that issue.
-
 ## License
 
 `ChatLayout` is distributed under [the MIT license](https://github.com/ekazaev/ChatLayout/blob/master/LICENSE).

README.md

@@ -21,23 +21,23 @@
     <header class="header">
       <p class="header-col header-col--primary">
         <a class="header-link" href="../index.html">
-          ChatLayout 1.1.8 Docs
+          ChatLayout 1.1.10 Docs
         </a>
          (100% documented)
       </p>
 
-      <p class="header-col--secondary">
+      <div class="header-col--secondary">
         <form role="search" action="../search.json">
           <input type="text" placeholder="Search documentation" data-typeahead>
         </form>
-      </p>
+      </div>
 
 
     </header>
 
     <p class="breadcrumbs">
       <a class="breadcrumb" href="../index.html">ChatLayout Reference</a>
-      <img class="carat" src="../img/carat.png" />
+      <img class="carat" src="../img/carat.png" alt=""/>
       CellLayoutContainerView Class Reference
     </p>
 
@@ -457,9 +457,8 @@ <h4>Parameters</h4>
       </article>
     </div>
     <section class="footer">
-      <p>&copy; 2021 <a class="link" href="https://github.com/ekazaev" target="_blank" rel="external">Evgeny Kazaev</a>. All rights reserved. (Last updated: 2021-05-15)</p>
-      <p>Generated by <a class="link" href="https://github.com/realm/jazzy" target="_blank" rel="external">jazzy ♪♫ v0.13.6</a>, a <a class="link" href="https://realm.io" target="_blank" rel="external">Realm</a> project.</p>
+      <p>&copy; 2021 <a class="link" href="https://github.com/ekazaev" target="_blank" rel="external noopener">Evgeny Kazaev</a>. All rights reserved. (Last updated: 2021-10-07)</p>
+      <p>Generated by <a class="link" href="https://github.com/realm/jazzy" target="_blank" rel="external noopener">jazzy ♪♫ v0.14.1</a>, a <a class="link" href="https://realm.io" target="_blank" rel="external noopener">Realm</a> project.</p>
     </section>
   </body>
-</div>
 </html>