Merge pull request #14 from zzzworm/master

Fix setting `currentPage` with a wrong value when `animated` is true

Author: amirdew

Lib/CollectionViewPagingLayout.swift

@@ -65,6 +65,7 @@ public class CollectionViewPagingLayout: UICollectionViewLayout {
 
 
     // MARK: UICollectionViewLayout
+    var ignoreUpdateCurrentPage : Bool = false
 
     override public func shouldInvalidateLayout(forBoundsChange newBounds: CGRect) -> Bool {
         true
@@ -129,7 +130,9 @@ public class CollectionViewPagingLayout: UICollectionViewLayout {
 
     override public func invalidateLayout() {
         super.invalidateLayout()
-        updateCurrentPageIfNeeded()
+        if !ignoreUpdateCurrentPage{
+            updateCurrentPageIfNeeded()
+        }
     }
 
 
@@ -174,7 +177,14 @@ public class CollectionViewPagingLayout: UICollectionViewLayout {
         offset = max(0, offset)
         offset = min(offset, maxPossibleOffset)
         let contentOffset: CGPoint = scrollDirection == .horizontal ? CGPoint(x: offset, y: 0) : CGPoint(x: 0, y: offset)
+        ignoreUpdateCurrentPage = true
+        CATransaction.begin()
+        CATransaction.setCompletionBlock({
+            self.ignoreUpdateCurrentPage = false
+            self.updateCurrentPageIfNeeded(basedOn: contentOffset)
+        })
         collectionView?.setContentOffset(contentOffset, animated: animated)
-        updateCurrentPageIfNeeded(basedOn: contentOffset)
+        CATransaction.commit()
+        
     }
 }