ios storyboard duplicated CollectionView cellForItemAtIndexPath not called

Question

Things I want to do

Duplicate a CollectionView From ControllerA to ControllerB in storyboard

Things I have done

Duplicate(CMD+D) CollectionView From ControllerA(which works fine) Drag Drop to ControllerB

retarget(ctrl + drag) dataSource and delegate to ControllerB

It should be

duplicated collectionView should work fine like it in ControllerA

But result is

numberOfSectionsInCollectionView and numberOfItemsInSection are called But cellForItemAtIndexPath not called

Edit 1

the problem looks like related to the frame size of the CollectionView

CollectionView: size(320,50) flow layout,scroll horizontal

CollectionViewCell: size(50,50)

If I drag CollectionView height to 65,it works with a warning:(cellForItemAtIndexPath called)

the behavior of the UICollectionViewFlowLayout is not defined because: the item height must be less than the height of the UICollectionView minus the section insets top and bottom values.

if CollectionView height >= 114,works without warning.

ControllerA with same parameters size(320,50) will work.don't know why

Edit 2

if I duplicate the CollectionView with all same settings and retarget to same delegate. the duplicate one doesn't work as expected. But the original one works!! weird!!

Answer 1

After upgrade to xcode 6 beta 5, I notice the cell is not in the visible area of CollectionView

Solution:

toggle off Adjust Scroll View Insets option in parent view controller attribute inspector or add this code to parent view controller viewDidLoad method: self.automaticallyAdjustsScrollViewInsets = NO;

ref:UICollectionView adds top margin