如何为内容单元格应用不同的contentInset，但不为UICollectionView中的标题应用

Question

I use insetForSectionAtIndex method to set contentInset for a section in my collection view and I don't want to apply that inset to a header of the section. I need the header width to be as wide as the screen.

ConentInset

func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets {
    if section == 1 {
        return UIEdgeInsets(top: 0, left: 15, bottom: 0, right: 15)
    }

    return UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
}

Header

override func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {

    let header = collectionView.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: opsMainDescriptionSegmentedControlCellId, forIndexPath: indexPath) as! MyHeader

    return header
}

Answer 1

I just had to do this exact same thing in one of my project.

The solution I applied:

In Storyboard, my collection view takes up the full screen with Auto-Layout constraints.

In viewDidLoad:

collectionView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)

I set the collectionView delegate to self and also conform to the

UICollectionViewDelegateFlowLayout protocol.

You then have access to the method you've used where I return another UIEdgeInsets

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {

        return UIEdgeInsets(top: 15, left: 20, bottom: 15, right: 20)

    }

and it worked for me.

See how it looked in the end.

Hope this will be able to help others.

Answer 2

You cannot do this. UICollectionViews headers need to be as wide as the UICollectionView itself. If you want the header to be shorter (width) than the UICollectionView - my suggestion is to use a separate UIView inside the header and set the header to clear. That way it will appear that its shorter than the width of the UICollectionView .