Change event call point from scrollViewDidScroll to scrollViewDidEndDecelerating for swipeViewCurrentItemIndexDidChange

SwipeView.podspec

@@ -10,4 +10,5 @@ Pod::Spec.new do |s|
   s.source_files = 'SwipeView'
   s.requires_arc = true
   s.platform     = :ios
+  s.ios.deployment_target = '7.0'
 end

SwipeView/SwipeView.h

@@ -59,8 +59,8 @@ typedef NS_ENUM(NSUInteger, SwipeViewAlignment)
 
 @interface SwipeView : UIView
 
-@property (nonatomic, weak_delegate) IBOutlet id<SwipeViewDataSource> dataSource;
-@property (nonatomic, weak_delegate) IBOutlet id<SwipeViewDelegate> delegate;
+@property (nonatomic, weak) IBOutlet id<SwipeViewDataSource> dataSource;
+@property (nonatomic, weak) IBOutlet id<SwipeViewDelegate> delegate;
 @property (nonatomic, readonly) NSInteger numberOfItems;
 @property (nonatomic, readonly) NSInteger numberOfPages;
 @property (nonatomic, readonly) CGSize itemSize;
@@ -85,6 +85,7 @@ typedef NS_ENUM(NSUInteger, SwipeViewAlignment)
 @property (nonatomic, readonly, getter = isScrolling) BOOL scrolling;
 @property (nonatomic, assign) BOOL defersItemViewLoading;
 @property (nonatomic, assign, getter = isVertical) BOOL vertical;
+@property (nonatomic, readonly) UIScrollView *scrollView;
 
 - (void)reloadData;
 - (void)reloadItemAtIndex:(NSInteger)index;

SwipeView/SwipeView.m

@@ -48,7 +48,6 @@
 #error This class requires automatic reference counting
 #endif
 
-
 @implementation NSObject (SwipeView)
 
 - (CGSize)swipeViewItemSize:(__unused SwipeView *)swipeView { return CGSizeZero; }
@@ -64,13 +63,30 @@ - (void)swipeView:(__unused SwipeView *)swipeView didSelectItemAtIndex:(__unused
 
 @end
 
+@interface SwipeScrollView : UIScrollView
+@property (nonatomic, getter=isVertical) BOOL vertical;
+@end
+
+@implementation SwipeScrollView
+
+- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRequireFailureOfGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
+        if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
+            CGPoint velocity = [((UIPanGestureRecognizer *) gestureRecognizer) velocityInView:self];
+            return _vertical ? ABS(velocity.y) < ABS(velocity.x) : ABS(velocity.x) > ABS(velocity.y);
+        }
+    return NO;
+}
+
+@end
+
 
 @interface SwipeView () <UIScrollViewDelegate, UIGestureRecognizerDelegate>
 
 @property (nonatomic, strong) UIScrollView *scrollView;
+@property (nonatomic, strong) SwipeScrollView *castedScrollView;
 @property (nonatomic, strong) NSMutableDictionary *itemViews;
 @property (nonatomic, strong) NSMutableSet *itemViewPool;
-@property (nonatomic, assign) NSInteger previousItemIndex;
+@property (nonatomic, assign) NSInteger selectedItemIndex;
 @property (nonatomic, assign) CGPoint previousContentOffset;
 @property (nonatomic, assign) CGSize itemSize;
 @property (nonatomic, assign) BOOL suppressScrollEvent;
@@ -85,7 +101,6 @@ @interface SwipeView () <UIScrollViewDelegate, UIGestureRecognizerDelegate>
 
 @end
 
-
 @implementation SwipeView
 
 #pragma mark -
@@ -103,7 +118,7 @@ - (void)setUp
     _defersItemViewLoading = NO;
     _vertical = NO;
 
-    _scrollView = [[UIScrollView alloc] init];
+    _scrollView = [[SwipeScrollView alloc] init];
     _scrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;
     _scrollView.autoresizesSubviews = YES;
     _scrollView.delegate = self;
@@ -121,7 +136,7 @@ - (void)setUp
 
     _decelerationRate = _scrollView.decelerationRate;
     _itemViews = [[NSMutableDictionary alloc] init];
-    _previousItemIndex = 0;
+    _selectedItemIndex = 0;
     _previousContentOffset = _scrollView.contentOffset;
     _scrollOffset = 0.0f;
     _currentItemIndex = 0;
@@ -273,7 +288,7 @@ - (void)setDecelerationRate:(float)decelerationRate
 
 - (void)setAutoscroll:(CGFloat)autoscroll
 {
-    if (fabs(_autoscroll - autoscroll) > 0.0001f)
+    if (fabsf(_autoscroll - autoscroll) > 0.0001f)
     {
         _autoscroll = autoscroll;
         if (autoscroll) [self startAnimation];
@@ -287,6 +302,7 @@ - (void)setVertical:(BOOL)vertical
         _vertical = vertical;
         _scrollView.alwaysBounceHorizontal = !_vertical && _bounces;
         _scrollView.alwaysBounceVertical = _vertical && _bounces;
+        self.castedScrollView.vertical = _vertical;
         [self setNeedsLayout];
     }
 }
@@ -391,11 +407,11 @@ - (void)updateScrollOffset
             _scrollOffset = [self clampedOffset:_scrollOffset];
         }
     }
-    if (_vertical && fabs(_scrollView.contentOffset.x) > 0.0001f)
+    if (_vertical && fabsf(_scrollView.contentOffset.x) > 0.0001f)
     {
         [self setContentOffsetWithoutEvent:CGPointMake(0.0f, _scrollView.contentOffset.y)];
     }
-    else if (!_vertical && fabs(_scrollView.contentOffset.y) > 0.0001f)
+    else if (!_vertical && fabsf(_scrollView.contentOffset.y) > 0.0001f)
     {
         [self setContentOffsetWithoutEvent:CGPointMake(_scrollView.contentOffset.x, 0.0f)];
     }
@@ -613,21 +629,13 @@ - (void)didScroll
     [self layOutItemViews];
     [_delegate swipeViewDidScroll:self];
 
-    if (!_defersItemViewLoading || fabs([self minScrollDistanceFromOffset:_lastUpdateOffset toOffset:_scrollOffset]) >= 1.0f)
+    if (!_defersItemViewLoading || fabsf([self minScrollDistanceFromOffset:_lastUpdateOffset toOffset:_scrollOffset]) >= 1.0f)
     {
-        //update item index
         _currentItemIndex = [self clampedIndex:roundf(_scrollOffset)];
 
         //load views
         _lastUpdateOffset = _currentItemIndex;
         [self loadUnloadViews];
-
-        //send index update event
-        if (_previousItemIndex != _currentItemIndex)
-        {
-            _previousItemIndex = _currentItemIndex;
-            [_delegate swipeViewCurrentItemIndexDidChange:self];
-        }
     }
 }
 
@@ -670,6 +678,7 @@ - (void)step
     else
     {
         [self stopAnimation];
+        [self changeSelectedIndex];
     }
 }
 
@@ -773,14 +782,15 @@ - (CGFloat)minScrollDistanceFromOffset:(CGFloat)fromOffset toOffset:(CGFloat)toO
         {
             wrappedDistance = -wrappedDistance;
         }
-        return (fabs(directDistance) <= fabs(wrappedDistance))? directDistance: wrappedDistance;
+        return (fabsf(directDistance) <= fabsf(wrappedDistance))? directDistance: wrappedDistance;
     }
     return directDistance;
 }
 
 - (void)setCurrentItemIndex:(NSInteger)currentItemIndex
 {
     _currentItemIndex = currentItemIndex;
+    _selectedItemIndex = currentItemIndex;
     self.scrollOffset = currentItemIndex;
 }
 
@@ -794,7 +804,7 @@ - (void)setCurrentPage:(NSInteger)currentPage
 
 - (void)setScrollOffset:(CGFloat)scrollOffset
 {
-    if (fabs(_scrollOffset - scrollOffset) > 0.0001f)
+    if (fabsf(_scrollOffset - scrollOffset) > 0.0001f)
     {
         _scrollOffset = scrollOffset;
         _lastUpdateOffset = _scrollOffset - 1.0f; //force refresh
@@ -826,9 +836,15 @@ - (void)scrollByOffset:(CGFloat)offset duration:(NSTimeInterval)duration
     else
     {
         self.scrollOffset += offset;
+        [self changeSelectedIndex];
     }
 }
 
+- (SwipeScrollView *)castedScrollView
+{
+    return (SwipeScrollView *) _scrollView;
+}
+
 - (void)scrollToOffset:(CGFloat)offset duration:(NSTimeInterval)duration
 {
     [self scrollByOffset:[self minScrollDistanceFromOffset:_scrollOffset toOffset:offset] duration:duration];
@@ -855,7 +871,7 @@ - (void)scrollByNumberOfItems:(NSInteger)itemCount duration:(NSTimeInterval)dura
     }
     else
     {
-        self.scrollOffset = [self clampedIndex:_previousItemIndex + itemCount];
+        self.scrollOffset = [self clampedIndex:_currentItemIndex + itemCount];
     }
 }
 
@@ -1172,6 +1188,7 @@ - (void)scrollViewDidEndDragging:(__unused UIScrollView *)scrollView willDeceler
         //force refresh
         _lastUpdateOffset = self.scrollOffset - 1.0f;
         [self didScroll];
+        [self changeSelectedIndex];
     }
     [_delegate swipeViewDidEndDragging:self willDecelerate:decelerate];
 }
@@ -1185,7 +1202,7 @@ - (void)scrollViewDidEndDecelerating:(__unused UIScrollView *)scrollView
 {
     //prevent rounding errors from accumulating
     CGFloat integerOffset = roundf(_scrollOffset);
-    if (fabs(_scrollOffset - integerOffset) < 0.01f)
+    if (fabsf(_scrollOffset - integerOffset) < 0.01f)
     {
         _scrollOffset = integerOffset;
     }
@@ -1195,6 +1212,17 @@ - (void)scrollViewDidEndDecelerating:(__unused UIScrollView *)scrollView
     [self didScroll];
 
     [_delegate swipeViewDidEndDecelerating:self];
+    [self changeSelectedIndex];
+}
+
+- (void)changeSelectedIndex {
+    NSInteger index = [self clampedIndex:roundf(_scrollOffset)];
+
+    if (index != _selectedItemIndex) {
+        _selectedItemIndex = index;
+
+        [_delegate swipeViewCurrentItemIndexDidChange:self];
+    }
 }
 
 @end