UITableView with ALAssets

ViewControllerStudentsList.m

@interface ViewControllerStudentsList ()

@property (strong, nonatomic) NSManagedObjectContext *managedObjectContext;
@property (strong, nonatomic) UIManagedDocument *document;

@property (nonatomic) NSInteger studentCount;
@property (strong, nonatomic) NSMutableArray *studentList;
@property (strong, nonatomic) NSMutableDictionary *studentPortraits;

@end

@implementation ViewControllerStudentsList

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"studentCell";
    
    StudentTableCell *cell = (StudentTableCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    
    if (cell == nil) {
        // Never gets called
    }
    
    Student *student = self.studentList[indexPath.row];
    
    cell.nameFirst.text = student.nameFirst;
    cell.nameLast.text = student.portrait.assetURL;
    
    // Portrait
    UIImage *portrait = [self cachedStudentPortrait:student atIndexPath:(NSIndexPath *)indexPath];
    if (!portrait) {
        portrait = [UIImage imageNamed:@"portrait-placeholder-1"];
    }
    cell.portrait.image = portrait;
    
    return cell;
}

- (UIImage *)cachedStudentPortrait:(Student *)student atIndexPath:(NSIndexPath *)indexPath
{
    UIImage *portrait = nil;
    NSString *objectClassName = NSStringFromClass([self.studentPortraits[student.studentID] class]);
    
    if ([objectClassName isEqualToString:@"UIImage"]) {
        portrait = self.studentPortraits[student.studentID];
    } else {
        ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
        NSLog(@"student.portrait.assetURL: %@", student.portrait.assetURL);
        [library assetForURL:[NSURL URLWithString:student.portrait.assetURL] resultBlock:^(ALAsset *asset) {
            ALAssetRepresentation *representation = [asset defaultRepresentation];
            CGImageRef assetRef = [representation fullResolutionImage];
            if (assetRef) {
                self.studentPortraits[student.studentID] = [UIImage imageWithCGImage:assetRef];
                [self.table reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationNone];
            }
        } failureBlock:^(NSError *error) {
            // error handling
            NSLog(@"failed to load");
        }];
    }
    
    return portrait;
}

@end