[photos] Fix a severe bug that caused photos to never load when scrub…

…bing. We weren't properly removing the photo tag from the loading queue when a photo request was canceled, causing the controller to think that photos were perpetually loading even though the operation had been canceled.
jverkoey · Jan 31, 2012 · 9081680 · 9081680
1 parent e044af0
commit 9081680
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Showing 4 changed files with 38 additions and 5 deletions.
diff --git a/examples/photos/NetworkPhotoAlbums/src/DribbblePhotoAlbumViewController.m b/examples/photos/NetworkPhotoAlbums/src/DribbblePhotoAlbumViewController.m
@@ -261,6 +261,9 @@ - (void)photoAlbumScrollView: (NIPhotoAlbumScrollView *)photoAlbumScrollView
   for (NIOperation* op in [self.queue operations]) {
     if (op.tag == photoIndex) {
       [op cancel];
+
+      [self didCancelRequestWithPhotoSize:NIPhotoScrollViewPhotoSizeOriginal
+                               photoIndex:photoIndex];
     }
   }
 }

diff --git a/examples/photos/NetworkPhotoAlbums/src/FacebookPhotoAlbumViewController.m b/examples/photos/NetworkPhotoAlbums/src/FacebookPhotoAlbumViewController.m
@@ -285,6 +285,9 @@ - (void)photoAlbumScrollView: (NIPhotoAlbumScrollView *)photoAlbumScrollView
   for (NIOperation* op in [self.queue operations]) {
     if (op.tag == photoIndex) {
       [op cancel];
+
+      [self didCancelRequestWithPhotoSize:NIPhotoScrollViewPhotoSizeOriginal
+                               photoIndex:photoIndex];
     }
   }
 }

diff --git a/examples/photos/NetworkPhotoAlbums/src/NetworkPhotoAlbumViewController.h b/examples/photos/NetworkPhotoAlbums/src/NetworkPhotoAlbumViewController.h
@@ -101,4 +101,7 @@
                      photoSize: (NIPhotoScrollViewPhotoSize)photoSize
                     photoIndex: (NSInteger)photoIndex;
 
+- (void)didCancelRequestWithPhotoSize:(NIPhotoScrollViewPhotoSize)photoSize
+                           photoIndex:(NSInteger)photoIndex;
+
 @end
diff --git a/examples/photos/NetworkPhotoAlbums/src/NetworkPhotoAlbumViewController.m b/examples/photos/NetworkPhotoAlbums/src/NetworkPhotoAlbumViewController.m
@@ -57,12 +57,27 @@ - (NSString *)cacheKeyForPhotoIndex:(NSInteger)photoIndex {
 
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
-- (void)requestImageFromSource: (NSString *)source
-                     photoSize: (NIPhotoScrollViewPhotoSize)photoSize
-                    photoIndex: (NSInteger)photoIndex {
+- (NSInteger)identifierWithPhotoSize:(NIPhotoScrollViewPhotoSize)photoSize
+                          photoIndex:(NSInteger)photoIndex {
   BOOL isThumbnail = (NIPhotoScrollViewPhotoSizeThumbnail == photoSize);
   NSInteger identifier = isThumbnail ? -(photoIndex + 1) : photoIndex;
-  NSNumber* identifierKey = [NSNumber numberWithInt:identifier];
+  return identifier;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+- (id)identifierKeyFromIdentifier:(NSInteger)identifier {
+  return [NSNumber numberWithInt:identifier];
+}
+
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+- (void)requestImageFromSource:(NSString *)source
+                     photoSize:(NIPhotoScrollViewPhotoSize)photoSize
+                    photoIndex:(NSInteger)photoIndex {
+  BOOL isThumbnail = (NIPhotoScrollViewPhotoSizeThumbnail == photoSize);
+  NSInteger identifier = [self identifierWithPhotoSize:photoSize photoIndex:photoIndex];
+  id identifierKey = [self identifierKeyFromIdentifier:identifier];
 
   // Avoid duplicating requests.
   if ([_activeRequests containsObject:identifierKey]) {
@@ -77,7 +92,7 @@ - (void)requestImageFromSource: (NSString *)source
 
   // Set an negative index for thumbnail requests so that they don't get cancelled by
   // photoAlbumScrollView:stopLoadingPhotoAtIndex:
-  readOp.tag = isThumbnail ? -(photoIndex + 1) : photoIndex;
+  readOp.tag = identifier;
 
   NSString* photoIndexKey = [self cacheKeyForPhotoIndex:photoIndex];
 
@@ -135,6 +150,15 @@ - (void)requestImageFromSource: (NSString *)source
 }
 
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+- (void)didCancelRequestWithPhotoSize:(NIPhotoScrollViewPhotoSize)photoSize
+                           photoIndex:(NSInteger)photoIndex {
+  NSInteger identifier = [self identifierWithPhotoSize:photoSize photoIndex:photoIndex];
+  id identifierKey = [self identifierKeyFromIdentifier:identifier];
+  [_activeRequests removeObject:identifierKey];
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 #pragma mark -