Merge pull request #84 from MerrickSapsford/infinite-scroll-fix

Infinite scroll fix
msaps · Aug 16, 2016 · 21afe23 · 21afe23
2 parents 3ff0bb8 + 913ad7b
commit 21afe23
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Showing 3 changed files with 24 additions and 9 deletions.
diff --git a/Source/Components/MSSPageViewController/MSSPageViewController+Private.h b/Source/Components/MSSPageViewController/MSSPageViewController+Private.h
@@ -8,16 +8,12 @@
 
 #import "MSSPageViewController.h"
 
-@interface MSSPageViewController () <UIScrollViewDelegate>
+@interface MSSPageViewController ()
 
 /**
  The default page index of the page view controller.
  */
 @property (nonatomic, assign, readonly) NSInteger defaultPageIndex;
-/**
- The current active page index of the page view controller.
- */
-@property (nonatomic, assign) NSInteger currentPage;
 /**
  Whether user interaction is currently enabled on the page view controller
  */

diff --git a/Source/Components/MSSPageViewController/MSSPageViewController.h b/Source/Components/MSSPageViewController/MSSPageViewController.h
@@ -107,7 +107,7 @@ willDisplayInitialViewController:(nonnull UIViewController *)viewController;
 
 @end
 
-@interface MSSPageViewController : UIViewController <MSSPageViewControllerDelegate, MSSPageViewControllerDataSource>
+@interface MSSPageViewController : UIViewController <MSSPageViewControllerDelegate, MSSPageViewControllerDataSource, UIScrollViewDelegate>
 
 /**
  The object that acts as a data source for the page view controller.
@@ -122,6 +122,10 @@ willDisplayInitialViewController:(nonnull UIViewController *)viewController;
  The number of pages in the page view controller.
  */
 @property (nonatomic, assign ,readonly) NSInteger numberOfPages;
+/**
+ The current active page index of the page view controller.
+ */
+@property (nonatomic, assign, readonly) NSInteger currentPage;
 /** 
  The view controllers within the page view controller.
  */
@@ -190,6 +194,11 @@ willDisplayInitialViewController:(nonnull UIViewController *)viewController;
                  animated:(BOOL)animated
                completion:(nullable MSSPageViewControllerPageMoveCompletion)completion;
 
+
+/** UIScrollViewDelegate */
+- (void)scrollViewWillBeginDragging:(nonnull UIScrollView *)scrollView NS_REQUIRES_SUPER;
+- (void)scrollViewDidScroll:(nonnull UIScrollView *)scrollView NS_REQUIRES_SUPER;
+
 @end
 
 @interface UIViewController (MSSPageViewController)

diff --git a/Source/Components/MSSPageViewController/MSSPageViewController.m b/Source/Components/MSSPageViewController/MSSPageViewController.m
@@ -218,7 +218,7 @@ - (void)setUpPages {
         [self setUpViewControllers:self.viewControllers];
 
         _numberOfPages = self.viewControllers.count;
-        self.currentPage = self.defaultPageIndex;
+        _currentPage = self.defaultPageIndex;
 
         if ([self.delegate respondsToSelector:@selector(pageViewController:didPrepareViewControllers:)]) {
             [self.delegate pageViewController:self didPrepareViewControllers:self.viewControllers];
@@ -284,6 +284,14 @@ - (UIScrollView *)scrollView {
 }
 
 - (void)updateCurrentPage:(NSInteger)currentPage {
+    if (self.infiniteScrollEnabled) {
+        if (currentPage >= self.numberOfPages) {
+            currentPage = 0;
+        } else if (currentPage < 0) {
+            currentPage = self.numberOfPages - 1;
+        }
+    }
+
     if (currentPage >= 0 && currentPage < self.numberOfPages) {
         _currentPage = currentPage;
         if ([self.delegate respondsToSelector:@selector(pageViewController:didScrollToPage:)]) {
@@ -309,13 +317,15 @@ - (void)scrollViewDidScroll:(UIScrollView *)scrollView {
     currentPagePosition > _previousPagePosition ?
     MSSPageViewControllerScrollDirectionForward : MSSPageViewControllerScrollDirectionBackward;
 
-    // check if reached a page incase page view controller delegate does not report
+    // check if reached a page as page view controller delegate does not report reliably
     // occurs when scrollview is continuously dragged
     if (!self.isAnimatingPageUpdate) {
         if (direction == MSSPageViewControllerScrollDirectionForward && currentPagePosition >= self.currentPage + 1) {
             [self updateCurrentPage:self.currentPage + 1];
+            return; // ignore update if we've changed page
         } else if (direction == MSSPageViewControllerScrollDirectionBackward && currentPagePosition <= self.currentPage - 1) {
             [self updateCurrentPage:self.currentPage - 1];
+            return;
         }
     }
 
@@ -352,7 +362,7 @@ - (void)scrollViewDidScroll:(UIScrollView *)scrollView {
                 currentPagePosition = MAX(0.0f, MIN(currentPagePosition, self.numberOfPages - 1));
             }
         }
-
+        
         // check whether updates are allowed
         if (self.scrollUpdatesEnabled && self.allowScrollViewUpdates) {
             if ([self.delegate respondsToSelector:@selector(pageViewController:didScrollToPageOffset:direction:)]) {