CODEWITHSUNDEEP
iosobjective-cuicollectionview
Fry
Fry

Reputation: 6275

UICollectionView viewForSupplementaryElementOfKind called three times

I've a UIViewController with a UICollectionView attached on it. The problem is that viewForSupplementaryElementOfKind is called three times and not just one like in UITableView.

Ideas ?

Upvotes: 3

Views: 2624

Answers (3)

michael wang
michael wang

Reputation: 551

i do not know exactly why this happened, but i have a weird solution. before you return the UICollectionReusableView in the viewForSupplementaryElementOfKind methord,check the num of datasource,just like this

if kind == CHTCollectionElementKindSectionHeader
    {

        if let header = collectionView.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: String(ImageDetailHeaderView), forIndexPath: indexPath) as? ImageDetailHeaderView
        {
            let bannerViewModel=ImageDetailHeaderVM(requestUrlStr: viewModel.headerRequestUrlStr, requestParams: viewModel.headerRequestParams)
            if vm.cellModelList.count>0
            {
                ***// only the datasource is not empty ,config the SupplementaryView***
                header.vm=bannerViewModel
                header.tagClickedHandler=tagClickedHandler
                header.shareButtonClicked=shareButtonClicked
                header.delegate=self
            }
            return header

        }
    }

Upvotes: 1

Sam
Sam

Reputation: 59

This is actually going to happen N times depending on whether you're reloading the collection view or scrolling the sections out of view and bringing them back. The viewForSupplementaryElementOfKind is going to get called whenever a section that has a header or footer gets displayed in the view

Upvotes: 0

Anil Varghese
Anil Varghese

Reputation: 42977

For UICollectionView supplementary view's are nothing but Section Header and Section Footer. viewForSupplementaryElementOfKind called two times for each section if you have already registered Classes for UICollectionElementKindSectionHeader and UICollectionElementKindSectionFooter. So the calling of viewForSupplementaryElementOfKind is depending on the number of the sections and availability of Section header/footer

Upvotes: 1

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