how to place two collection views on top of a UIView with a UIImage view in between

Question

iOS Simulator Screen shot Jun 19, 2013 2.43.43 PM.png!Main Storyboard description

Answer 1

This is really simple. In your collection view datasource methods, make sure you distinguish between the two views by keeping strong references to the views e.g. as properties:

if (collectionView == _topCollectionView) {
   // provide the data for the top view
}
else {
   // provide the data for the bottom view
}

Do the same in didSelectItemAtIndexPath. Determine which collection view has been interacted with, change the appropriate data in for the other one and reload and/or update your image view.

You need to use a standard view controller and add the delegate and datasource declarations manually.

@interface ViewController : UIViewController 
         <UICollectionViewDataSource, UICollectionViewDelegate>