Infinite loop slideshow

CHANGELOG.md

@@ -6,6 +6,7 @@ Changes for users of the library currently on `develop`:
     - A data source no longer has to handle out-of-bounds indexes ([#227](https://github.com/NYTimes/NYTPhotoViewer/pull/227))
     - The data source is not retained ([#227](https://github.com/NYTimes/NYTPhotoViewer/pull/227))
 - Respect safe areas for iOS 11 support
+- Ability to create an infinite loop slideshow 
 
 ## [1.2.0](https://github.com/NYTimes/NYTPhotoViewer/releases/tag/1.2.0)
 

NYTPhotoViewer/NYTPhotosViewController.h

@@ -98,6 +98,11 @@ extern NSString * const NYTPhotosViewControllerDidDismissNotification;
  */
 @property (nonatomic, weak, nullable) id <NYTPhotosViewControllerDelegate> delegate;
 
+/**
+ *  Enable a loop navigation between last photo and first photo
+ */
+@property (nonatomic) BOOL canLoop;
+
 /**
  *  Initializes a `PhotosViewController` with the given data source, initially displaying the first photo in the data source.
  *

NYTPhotoViewer/NYTPhotosViewController.m

@@ -572,6 +572,11 @@ - (void)photoViewController:(NYTPhotoViewController *)photoViewController didLon
 - (UIViewController *)pageViewController:(UIPageViewController *)pageViewController viewControllerBeforeViewController:(UIViewController <NYTPhotoContainer> *)viewController {
     NSUInteger photoIndex = [self.dataSource indexOfPhoto:viewController.photo];
     if (photoIndex == 0 || photoIndex == NSNotFound) {
+
+        if (self.canLoop && self.dataSource.numberOfPhotos.integerValue > 1)  {
+            return [self newPhotoViewControllerForPhoto:[self.dataSource photoAtIndex:(self.dataSource.numberOfPhotos.integerValue - 1)]];
+        }
+
         return nil;
     }
 
@@ -583,6 +588,10 @@ - (UIViewController *)pageViewController:(UIPageViewController *)pageViewControl
     if (photoIndex == NSNotFound) {
         return nil;
     }
+
+    if (self.canLoop && photoIndex + 1 == self.dataSource.numberOfPhotos.integerValue) {
+        return [self newPhotoViewControllerForPhoto:[self.dataSource photoAtIndex:0]];
+    }
 
     return [self newPhotoViewControllerForPhoto:[self.dataSource photoAtIndex:(photoIndex + 1)]];
 }