Check if cell has been recycled before setting attachment image

* Ensure that when the FIC completion block is called that the cell has not been recycled
  and used for another attachment.

fixes #43

Author: newmanw

MAGE.xcodeproj/project.pbxproj

@@ -1021,7 +1021,7 @@
 				ORGANIZATIONNAME = "National Geospatial Intelligence Agency";
 				TargetAttributes = {
 					F7A94D6518AD9CB000CB9EE0 = {
-						DevelopmentTeam = A8EK924J35;
+						DevelopmentTeam = ZL8G5D9G2H;
 					};
 				};
 			};
@@ -1382,7 +1382,7 @@
 				INFOPLIST_FILE = "Mage/MAGE-Info.plist";
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				OTHER_LDFLAGS = "$(inherited)";
-				PRODUCT_BUNDLE_IDENTIFIER = mil.nga.giat.MAGE;
+				PRODUCT_BUNDLE_IDENTIFIER = mil.nga.mage;
 				PRODUCT_NAME = MAGE;
 				PROVISIONING_PROFILE = "";
 				WRAPPER_EXTENSION = app;
@@ -1404,7 +1404,7 @@
 				INFOPLIST_FILE = "Mage/MAGE-Info.plist";
 				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
 				OTHER_LDFLAGS = "$(inherited)";
-				PRODUCT_BUNDLE_IDENTIFIER = mil.nga.giat.MAGE;
+				PRODUCT_BUNDLE_IDENTIFIER = mil.nga.mage;
 				PRODUCT_NAME = MAGE;
 				PROVISIONING_PROFILE = "";
 				WRAPPER_EXTENSION = app;

Mage/AttachmentCell.h

@@ -6,8 +6,13 @@
 
 #import <UIKit/UIKit.h>
 
+@class Attachment;
+
 @interface AttachmentCell : UICollectionViewCell
 
 @property (weak, nonatomic) IBOutlet UIImageView *imageView;
+@property (strong, nonatomic) Attachment *attachment;
+
+-(void) setImageForAttachament:(Attachment *) attachment;
 
 @end

Mage/AttachmentCell.m

@@ -5,25 +5,32 @@
 //
 
 #import "AttachmentCell.h"
+#import "FICImageCache.h"
+#import "Attachment+FICAttachment.h"
+#import "AppDelegate.h"
 
 @implementation AttachmentCell
 
-- (id)initWithFrame:(CGRect)frame
-{
-    self = [super initWithFrame:frame];
-    if (self) {
-        // Initialization code
-    }
-    return self;
+- (void)prepareForReuse {
+    self.imageView.image = nil;
 }
 
-/*
-// Only override drawRect: if you perform custom drawing.
-// An empty implementation adversely affects performance during animation.
-- (void)drawRect:(CGRect)rect
-{
-    // Drawing code
+-(void) setImageForAttachament:(Attachment *) attachment {
+    self.attachment = attachment;
+    
+    self.imageView.image = [UIImage imageNamed:@"download"];
+    
+    AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
+    __weak typeof(self) weakSelf = self;
+    [delegate.imageCache retrieveImageForEntity:attachment withFormatName:AttachmentMediumSquare completionBlock:^(id<FICEntity> entity, NSString *formatName, UIImage *image) {
+        // This completion block may be called much later, check to make sure this cell hasn't been reused for a different attachment before displaying the image that has loaded.
+        if (attachment == [self attachment]) {
+            weakSelf.imageView.image = image;
+            [weakSelf.imageView.layer addAnimation:[CATransition animation] forKey:kCATransition];
+            weakSelf.imageView.layer.cornerRadius = 5;
+            weakSelf.imageView.clipsToBounds = YES;
+        }
+    }];
 }
-*/
 
 @end

Mage/AttachmentCollectionDataStore.m

@@ -12,42 +12,26 @@
 @implementation AttachmentCollectionDataStore
 
 - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {
-    NSMutableArray *allAttachments = [NSMutableArray arrayWithArray:[_observation.attachments allObjects]];
-    [allAttachments addObjectsFromArray:_observation.transientAttachments];
+    NSMutableArray *allAttachments = [NSMutableArray arrayWithArray:[self.observation.attachments allObjects]];
+    [allAttachments addObjectsFromArray:self.observation.transientAttachments];
 
-    AttachmentCell *cell = [_attachmentCollection dequeueReusableCellWithReuseIdentifier:@"AttachmentCell" forIndexPath:indexPath];
-    Attachment *attachment = [allAttachments objectAtIndex:[indexPath indexAtPosition:[indexPath length]-1]];
-    
-    FICImageCacheCompletionBlock completionBlock = ^(id <FICEntity> entity, NSString *formatName, UIImage *image) {
-        if (!image) return;
-        
-        cell.imageView.image = image;
-        [cell.imageView.layer addAnimation:[CATransition animation] forKey:kCATransition];
-        cell.imageView.layer.cornerRadius = 5;
-        cell.imageView.clipsToBounds = YES;
-    };
-    AppDelegate *delegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
-    
-    BOOL imageExists = [delegate.imageCache retrieveImageForEntity:attachment withFormatName:AttachmentMediumSquare completionBlock:completionBlock];
-    
-    if (imageExists == NO) {
-        cell.imageView.image = [UIImage imageNamed:@"download"];
-    }
+    AttachmentCell *cell = [self.attachmentCollection dequeueReusableCellWithReuseIdentifier:@"AttachmentCell" forIndexPath:indexPath];
+    Attachment *attachment = [allAttachments objectAtIndex:[indexPath row]];
+    [cell setImageForAttachament:attachment];
+
     return cell;
 }
 
 - (NSInteger) collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
-    return _observation.attachments.count + _observation.transientAttachments.count;
+    return self.observation.attachments.count + self.observation.transientAttachments.count;
 }
 
 - (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
-    NSMutableArray *allAttachments = [NSMutableArray arrayWithArray:[_observation.attachments allObjects]];
-    [allAttachments addObjectsFromArray:_observation.transientAttachments];
-    
-    Attachment *attachment = [allAttachments objectAtIndex:[indexPath indexAtPosition:[indexPath length]-1]];
-    NSLog(@"clicked attachment %@", attachment.url);
+    NSMutableArray *allAttachments = [NSMutableArray arrayWithArray:[self.observation.attachments allObjects]];
+    [allAttachments addObjectsFromArray:self.observation.transientAttachments];
 
     if (self.attachmentSelectionDelegate) {
+        Attachment *attachment = [allAttachments objectAtIndex:[indexPath row]];
         [self.attachmentSelectionDelegate selectedAttachment:attachment];
     }
 }