Gesture recognizers on subviews don't seem to work - objective-c

Question

I have code as the following:
- (void)setPosts:(NSArray *)posts
{
_posts = posts;
int totalHeight = 0;
for (TumblrPost *post in posts) {
totalHeight += post.thumbH;
}
dispatch_queue_t mainQ = dispatch_get_main_queue();
dispatch_async(mainQ, ^{
int cumulativeY = 0;
int postCount = 0;
for (TumblrPost *post in posts) {
NSArray* array = [[NSBundle mainBundle] loadNibNamed:#"ThumbnailView" owner:nil options:nil];
ThumbnailView* thumbnail = [array objectAtIndex:0];
thumbnail.frame = CGRectMake(0,cumulativeY,0,0);
thumbnail.userInteractionEnabled = YES;
UITapGestureRecognizer *gesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(showMainImage:)];
[thumbnail addGestureRecognizer:gesture];
[self.multiThumbnailView addSubview:thumbnail];
[thumbnail loadUrl:post.url];
cumulativeY+=100;//post.thumbH;
if(postCount >=2)
break;
postCount++;
}
NSLog(#"Set posts method");
});
}
- (void)showMainImage:(UITapGestureRecognizer *)gesture
{
if(gesture.state == UIGestureRecognizerStateChanged || gesture.state == UIGestureRecognizerStateEnded)
{
int thumbIndex = [self.multiThumbnailView.subviews indexOfObject:gesture.view];
self.selectedPost = (TumblrPost*)[self.posts objectAtIndex:thumbIndex];
[self performSegueWithIdentifier:#"ShowMainPost" sender:self];
}
}
multiThumbnailView is a UIView which I have in my storyboard and ThumbnailView is an xib/class combination which is a 100x100 square with a label in it that says 'test'.
When I run my code I get three boxes in a vertical line but the gesture recogniser doesn't fire when I click on my sub views. Everything has userInteractionEnabled ticked. I tried making a test gesturerecognizer on the main multiThumbnailView and that worked.
Please help!

Answer 1

My guess is that ThumbnailView is a subclass of UIImageView - which by default sets its userInteractionEnabled to NO.
Make sure that you set userInteractionEnabled = YES on every ThumbnailViewthat you want to intercept taps.
EDIT:
In addition, you set the frame of the ThumbnailView to be with size of (0,0).
That means that this view is basically invisible and thus won't intercept touches.
And finally, please don't do:
ThumbnailView* thumbnail = [array objectAtIndex:0];
Instead you can check the count of the array or simply:
ThumbnailView* thumbnail = [array lastObject];