UICollectionView：补充视图阻止项目选择

Question

I'm implementing calendar layout for UICollectionView . There are 'event' cells and 'current time' supplementary view. According to design I display 'current time' view above events.

The problem is that if user touches 'current time' view an 'event' cell can't be selected.

I tried to override - (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event method of supplementary view and return nil, bit it never called. userInteractionEnabled equals to YES for this supplementary view.

Any ideas how can I transfer touches from supplementary view to UICollectionView cells?

Answer 1

I don't completely understand what you are trying to achieve and maybe a bit of code would help but my guess is that you want to tap something in a header view and select today's events?

If so you need to capture the touch, maybe with a UIButton, in the supplementary view. Then you want to call

[_collectionView selectItemAtIndexPath:myIndexPath animated:YES scrollPosition:position];

If you are saying that touching the supplementary view blocks touches on the collection view I would check the frames as you may have something on top of something else and not realise. Maybe try and make the backgrounds of elements red etc to see what is where.

Answer 2

I think that the best way is to optimise you responder chain, look at Event Delivery: The Responder Chain

But if you are trying to do something really irregular in addition you always can handle user touches explicitly by some dedicated view. If you have got the coordinates of user touch then use UICollectionView method to get the index path of affected cell:

- (NSIndexPath *)indexPathForItemAtPoint:(CGPoint)point

Do not forget to convert the coordinates to the appropriate coordinate system using UIView method:

- (CGPoint)convertPoint:(CGPoint)point toView:(UIView *)view