CODEWITHSUNDEEP
iosuicollectionview
Mason Cloud
Mason Cloud

Reputation: 1306

How can I tell when the background (i.e. not a cell) is touched on a UICollectionView?

I've tried subclassing UICollectionView and overriding touchesBegan:withEvent: and hitTest:WithEvent:, and both of those methods trigger when I touch a cell. However, if I touch the space between the cells, nothing happens at all. Here's what I've created:

@interface WSImageGalleryCollectionView : UICollectionView
@end

..and..

@implementation WSImageGalleryCollectionView

- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    NSLog(@"Touches began");
    [super touchesBegan:touches withEvent:event];
}

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
    NSLog(@"Hit test reached");
    return [super hitTest:point withEvent:event];
}

@end

Note: gesture recognizers seem to have the exact same issue, which is why I tried going lower-level with touchesBegan.

Upvotes: 6

Views: 1843

Answers (3)

Michael Loistl
Michael Loistl

Reputation: 271

You just need to set a view as background view that you can then add a gesture recognizer to like:

collectionView.backgroundView = [[UIView alloc] init];
[collectionView.backgroundView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapOnBackgroundRecognized)]];

Upvotes: 12

Mason Cloud
Mason Cloud

Reputation: 1306

In my case, the problem was that you can click on the background whenever it is "clear" colored. Otherwise simply setting a background color makes the background clickable. I don't quite know why this is, but the simple fix was to just give it a background color.

Edit: Actually, this may have had something to do with setting the "opaque" flag.

Upvotes: 0

sergio
sergio

Reputation: 69027

You must have got something else that is preventing touchesBegan from firing.

Subclassing UICollectionView and using that subclass inside of a UICollectionViewController will allow you to detect in-between cells taps in touchesBegan.

I have just tried it out by modifying Apple's CollectionView-simple sample.

Upvotes: 0

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