Stack UICollectionView sections - ios

Question

I have a problem. I'm using a UICollectionView to display two (they will be more) arrays of images, and every array has its own section. I'd like to achieve something like:
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Section 1: Elements in array no. 1
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Section 2: Elements in array no. 2
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But as of now I get something like
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Section 1: Elements in array no. 1 | Elements in array no. 2
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How can I tell the UICollectionView to stack the two sections?
I thought about putting the collection view I have now into the cell of another collection view, but I have no idea how to do that.
Another solution may be to put them into the cell of a tableview, but it's best if I can avoid those workarounds.
I am not sure how to use it, but I think creating a custom layout may work, even if I need some help with that.
Also, I have been asked to not use any external library.
BTW I am programming in Objective-C.

Answer 1

You can make multiple section by simply implementing UICollectionViewDataSource method numberOfSectionsInCollectionView
class ViewController: UIViewController, UICollectionViewDataSource,UICollectionViewDelegateFlowLayout {
let HEADER_IDENTIFIER = "header_identifier"
let CELL_IDENTIFIER = "cell_identifier"
lazy var collectionView:UICollectionView = {
var cv = UICollectionView(frame: self.view.bounds, collectionViewLayout: self.flowLayout)
cv.delegate = self
cv.dataSource = self
cv.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: self.CELL_IDENTIFIER)
cv.registerClass(UICollectionReusableView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: self.HEADER_IDENTIFIER)
cv.backgroundColor = UIColor(red: 230/255, green: 230/255, blue: 230/255, alpha: 1)
return cv
}()
lazy var flowLayout:UICollectionViewFlowLayout = {
var flow = UICollectionViewFlowLayout()
flow.sectionInset = UIEdgeInsetsMake(2.0, 2.0, 2.0, 2.0)
return flow
}()
override func viewDidLoad() {
super.viewDidLoad()
self.view.addSubview(self.collectionView)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: UICollectionView
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCellWithReuseIdentifier(CELL_IDENTIFIER, forIndexPath: indexPath)
cell.backgroundColor = UIColor.blueColor()
return cell
}
func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {
let header = collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader, withReuseIdentifier: HEADER_IDENTIFIER, forIndexPath: indexPath)
header.backgroundColor = UIColor.redColor()
return header
}
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
return 2
}
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {
return CGSize(width: 90, height: 90) // The size of one cell
}
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
return CGSizeMake(self.view.frame.width, 1) // Header size
}
}