lxcid · hpique · Apr 1, 2013 · Apr 1, 2013 · Apr 1, 2013 · Apr 1, 2013
diff --git a/...mple using Storyboard/LXRCVFL Example using Storyboard/en.lproj/MainStoryboard.storyboard b/...mple using Storyboard/LXRCVFL Example using Storyboard/en.lproj/MainStoryboard.storyboard
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="2.0" toolsVersion="3084" systemVersion="12C3006" targetRuntime="iOS.CocoaTouch.iPad" propertyAccessControl="none" useAutolayout="YES" initialViewController="wfC-9f-vtC">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="2.0" toolsVersion="3084" systemVersion="12D78" targetRuntime="iOS.CocoaTouch.iPad" propertyAccessControl="none" useAutolayout="YES" initialViewController="wfC-9f-vtC">
     <dependencies>
         <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="2083"/>
     </dependencies>
@@ -8,7 +8,7 @@
         <scene sceneID="3Tg-sk-Lj5">
             <objects>
                 <collectionViewController autoresizesArchivedViewToFullSize="NO" id="wfC-9f-vtC" customClass="LXCollectionViewController" sceneMemberID="viewController">
-                    <collectionView key="view" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" minimumZoomScale="0.0" maximumZoomScale="0.0" dataMode="prototypes" id="jt6-40-vJL">
+                    <collectionView key="view" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" pagingEnabled="YES" minimumZoomScale="0.0" maximumZoomScale="0.0" dataMode="prototypes" id="jt6-40-vJL">
                         <rect key="frame" x="0.0" y="20" width="768" height="1004"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                         <collectionViewFlowLayout key="collectionViewLayout" minimumLineSpacing="10" minimumInteritemSpacing="10" id="zhp-KR-emn" customClass="LXReorderableCollectionViewFlowLayout">

diff --git a/LXReorderableCollectionViewFlowLayout/LXReorderableCollectionViewFlowLayout.m b/LXReorderableCollectionViewFlowLayout/LXReorderableCollectionViewFlowLayout.m
@@ -28,6 +28,51 @@ typedef NS_ENUM(NSInteger, LXScrollingDirection) {
 static NSString * const kLXScrollingDirectionKey = @"LXScrollingDirection";
 static NSString * const kLXCollectionViewKeyPath = @"collectionView";
 
+@interface UICollectionViewFlowLayout (LXPaging)
+
+- (CGPoint)LX_contentOffsetForPageIndex:(NSInteger)pageIndex;
+- (NSInteger)LX_currentPageIndex;
+- (NSInteger)LX_pageCount;
+
+@end
+
+@implementation UICollectionViewFlowLayout (LXPaging)
+
+- (NSInteger)LX_currentPageIndex {
+    switch (self.scrollDirection) {
+        case UICollectionViewScrollDirectionHorizontal: {
+            return round(self.collectionView.contentOffset.x / self.collectionView.frame.size.width);
+        }
+        case UICollectionViewScrollDirectionVertical: {
+            return round(self.collectionView.contentOffset.y / self.collectionView.frame.size.height);
+        }
+    }
+}
+
+- (NSInteger)LX_pageCount {
+    switch (self.scrollDirection) {
+        case UICollectionViewScrollDirectionHorizontal: {
+            return ceil(self.collectionViewContentSize.width / self.collectionView.frame.size.width);
+        }
+        case UICollectionViewScrollDirectionVertical: {
+            return ceil(self.collectionViewContentSize.height / self.collectionView.frame.size.height);
+        }
+    }
+}
+
+- (CGPoint)LX_contentOffsetForPageIndex:(NSInteger)pageIndex {
+    switch (self.scrollDirection) {
+        case UICollectionViewScrollDirectionHorizontal: {
+            return CGPointMake(self.collectionView.frame.size.width * pageIndex, 0);
+        }
+        case UICollectionViewScrollDirectionVertical: {
+            return CGPointMake(0, self.collectionView.frame.size.height * pageIndex);
+        }
+    }
+}
+
+@end
+
 @interface UICollectionViewCell (LXReorderableCollectionViewFlowLayout)
 
 - (UIImage *)LX_rasterizedImage;
@@ -59,7 +104,9 @@ @interface LXReorderableCollectionViewFlowLayout ()
 
 @end
 
-@implementation LXReorderableCollectionViewFlowLayout
+@implementation LXReorderableCollectionViewFlowLayout {
+    BOOL _pageScrollingDisabled;
+}
 
 - (void)setDefaults {
     _scrollingSpeed = 300.0f;
@@ -126,7 +173,8 @@ - (void)applyLayoutAttributes:(UICollectionViewLayoutAttributes *)layoutAttribut
 }
 
 - (void)invalidateLayoutIfNecessary {
-    NSIndexPath *newIndexPath = [self.collectionView indexPathForItemAtPoint:self.currentView.center];
+    const CGPoint point = [self.collectionView convertPoint:self.currentView.center fromView:self.collectionView.superview];
+    NSIndexPath *newIndexPath = [self.collectionView indexPathForItemAtPoint:point];
     NSIndexPath *previousIndexPath = self.selectedItemIndexPath;
 
     if ((newIndexPath == nil) || [newIndexPath isEqual:previousIndexPath]) {
@@ -159,6 +207,85 @@ - (void)invalidatesScrollTimer {
     self.scrollingTimer = nil;
 }
 
+- (void)scrollIfNecessary {
+    if (!self.currentView) return; // Prevent scrollToPageIndex to continue scrolling after the drag ended
+
+    const CGPoint viewCenter = [self.collectionView convertPoint:self.currentView.center fromView:self.collectionView.superview];
+    switch (self.scrollDirection) {
+        case UICollectionViewScrollDirectionVertical: {
+            if (viewCenter.y < (CGRectGetMinY(self.collectionView.bounds) + self.scrollingTriggerEdgeInsets.top)) {
+                [self scrollWithDirection:LXScrollingDirectionUp];
+            } else {
+                if (viewCenter.y > (CGRectGetMaxY(self.collectionView.bounds) - self.scrollingTriggerEdgeInsets.bottom)) {
+                    [self scrollWithDirection:LXScrollingDirectionDown];
+                } else {
+                    [self invalidatesScrollTimer];
+                }
+            }
+        } break;
+        case UICollectionViewScrollDirectionHorizontal: {
+            if (viewCenter.x < (CGRectGetMinX(self.collectionView.bounds) + self.scrollingTriggerEdgeInsets.left)) {
+                [self scrollWithDirection:LXScrollingDirectionLeft];
+            } else {
+                if (viewCenter.x > (CGRectGetMaxX(self.collectionView.bounds) - self.scrollingTriggerEdgeInsets.right)) {
+                    [self scrollWithDirection:LXScrollingDirectionRight];
+                } else {
+                    [self invalidatesScrollTimer];
+                }
+            }
+        } break;
+    }
+}
+
+- (void)scrollToPreviousPage {
+    if (_pageScrollingDisabled) return;
+    const NSInteger currentPage = [self LX_currentPageIndex];
+    if (currentPage <= 0) return;
+    const NSInteger newPage = currentPage - 1;
+    [self scrollToPageIndex:newPage forward:NO];
+}
+
+- (void)scrollToNextPage {
+    if (_pageScrollingDisabled) return;
+    const NSInteger currentPage = [self LX_currentPageIndex];
+    const NSInteger pageCount = [self LX_pageCount];
+    if (currentPage >= pageCount - 1) return;
+    const NSInteger newPage = currentPage + 1;
+    [self scrollToPageIndex:newPage forward:YES];
+}
+
+- (void)scrollToPageIndex:(NSInteger)pageIndex forward:(BOOL)forward {
+    const CGPoint offset = [self LX_contentOffsetForPageIndex:pageIndex];
+    [self.collectionView setContentOffset:offset animated:YES];
+
+    // Wait a little bit before changing page again
+    _pageScrollingDisabled = YES; 
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 1 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{ // Delay must be bigger than the contentOffset animation
+        _pageScrollingDisabled = NO;
+        [self scrollIfNecessary];
+    });
+}
+
+- (void)scrollWithDirection:(LXScrollingDirection)direction {
+    if (self.collectionView.pagingEnabled) {
+        switch(direction) {
+            case LXScrollingDirectionUp:
+            case LXScrollingDirectionLeft: {
+                [self scrollToPreviousPage];
+            } break;
+            case LXScrollingDirectionDown:
+            case LXScrollingDirectionRight: {
+                [self scrollToNextPage];
+            } break;
+            default: {
+                // Do nothing...
+            } break;
+        }
+    } else {
+        [self setupScrollTimerInDirection:direction];
+    }
+}
+
 - (void)setupScrollTimerInDirection:(LXScrollingDirection)direction {
     if (self.scrollingTimer.isValid) {
         LXScrollingDirection oldDirection = [self.scrollingTimer.userInfo[kLXScrollingDirectionKey] integerValue];
@@ -236,7 +363,6 @@ - (void)handleScroll:(NSTimer *)timer {
         } break;
     }
 
-    self.currentViewCenter = LXS_CGPointAdd(self.currentViewCenter, translation);
     self.currentView.center = LXS_CGPointAdd(self.currentViewCenter, self.panTranslationInCollectionView);
     self.collectionView.contentOffset = LXS_CGPointAdd(contentOffset, translation);
 }
@@ -274,7 +400,9 @@ - (void)handleLongPressGesture:(UILongPressGestureRecognizer *)gestureRecognizer
 
             [self.currentView addSubview:imageView];
             [self.currentView addSubview:highlightedImageView];
-            [self.collectionView addSubview:self.currentView];
+            const CGPoint center = [self.collectionView.superview convertPoint:collectionViewCell.center fromView:self.collectionView];
+            self.currentView.center = center;
+            [self.collectionView.superview addSubview:self.currentView];
 
             self.currentViewCenter = self.currentView.center;
 
@@ -326,7 +454,8 @@ - (void)handleLongPressGesture:(UILongPressGestureRecognizer *)gestureRecognizer
                      __strong typeof(self) strongSelf = weakSelf;
                      if (strongSelf) {
                          strongSelf.currentView.transform = CGAffineTransformMakeScale(1.0f, 1.0f);
-                         strongSelf.currentView.center = layoutAttributes.center;
+                         const CGPoint center = [strongSelf.collectionView.superview convertPoint:layoutAttributes.center fromView:strongSelf.collectionView];
+                         strongSelf.currentView.center = center;
                      }
                  }
                  completion:^(BOOL finished) {
@@ -352,41 +481,14 @@ - (void)handlePanGesture:(UIPanGestureRecognizer *)gestureRecognizer {
     switch (gestureRecognizer.state) {
         case UIGestureRecognizerStateBegan:
         case UIGestureRecognizerStateChanged: {
-            self.panTranslationInCollectionView = [gestureRecognizer translationInView:self.collectionView];
-            CGPoint viewCenter = self.currentView.center = LXS_CGPointAdd(self.currentViewCenter, self.panTranslationInCollectionView);
-
+            self.panTranslationInCollectionView = [gestureRecognizer translationInView:self.collectionView.superview];
+            self.currentView.center = LXS_CGPointAdd(self.currentViewCenter, self.panTranslationInCollectionView);            
             [self invalidateLayoutIfNecessary];
-
-            switch (self.scrollDirection) {
-                case UICollectionViewScrollDirectionVertical: {
-                    if (viewCenter.y < (CGRectGetMinY(self.collectionView.bounds) + self.scrollingTriggerEdgeInsets.top)) {
-                        [self setupScrollTimerInDirection:LXScrollingDirectionUp];
-                    } else {
-                        if (viewCenter.y > (CGRectGetMaxY(self.collectionView.bounds) - self.scrollingTriggerEdgeInsets.bottom)) {
-                            [self setupScrollTimerInDirection:LXScrollingDirectionDown];
-                        } else {
-                            [self invalidatesScrollTimer];
-                        }
-                    }
-                } break;
-                case UICollectionViewScrollDirectionHorizontal: {
-                    if (viewCenter.x < (CGRectGetMinX(self.collectionView.bounds) + self.scrollingTriggerEdgeInsets.left)) {
-                        [self setupScrollTimerInDirection:LXScrollingDirectionLeft];
-                    } else {
-                        if (viewCenter.x > (CGRectGetMaxX(self.collectionView.bounds) - self.scrollingTriggerEdgeInsets.right)) {
-                            [self setupScrollTimerInDirection:LXScrollingDirectionRight];
-                        } else {
-                            [self invalidatesScrollTimer];
-                        }
-                    }
-                } break;
-            }
-        } break;
-        case UIGestureRecognizerStateEnded: {
-            [self invalidatesScrollTimer];
+            [self scrollIfNecessary];
         } break;
+        case UIGestureRecognizerStateEnded:
         default: {
-            // Do nothing...
+            [self invalidatesScrollTimer];
         } break;
     }
 }