How to use single array in multiple collectionView sections? - ios

Question

I have single array which contain game`s informations. My Json has 12 items in a page. I did created 4 sections which has 3 rows. It is repeating first 3 items of array in every sections.
Screenshot from app
I want to use like that;
Total Items = 12
Section = 1 2 3
Section = 4 5 6
Section = 7 8 9
Section = 10 11 12
How can I do that ? Thanks in advance :)
func numberOfSections(in collectionView: UICollectionView) -> Int {
return id.count / 3
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "lastAddedCell", for: indexPath) as! lastAddedCell
cell.gameName.text = name[indexPath.row]
cell.gameImage.sd_setImage(with: URL(string:resimUrl[indexPath.row]))
return cell
}

Answer 1

I don't think it's such a good idea. I would rather create the section separately by making a section manager than making them from the same array. But, if you want to do it the way you are doing it right now. Here is an easy fix:
func numberOfSections(in collectionView: UICollectionView) -> Int {
return id.count / 3
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 3
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "lastAddedCell", for: indexPath) as! lastAddedCell
let index = indexPath.row + (indexPath.section * 3) // The index is then based on the section which is being presented
cell.gameName.text = name[index]
cell.gameImage.sd_setImage(with: URL(string:resimUrl[indexPath.row]))
return cell
}

Answer 2

Consider this case below and implement it,
var array = [1,2,3,4,5,6,7,8,9,10,11,12]
//Statcially you can slice them like this
var arr2 = array[0...2] {
didSet {
//reload your collection view
}
}
var arr3 = array[3...5]
var arr4 = array[6...8]
var arr5 = array[9...array.count - 1]
Above you manually sliced the dataSource for each UICollectionView but the problem is this is really risky and eventually can lead to an Index Out of Range crash, so we dynamically slice the array thru looping in it using the index of each element in range of +3 indexes to append to the new UICollectionView data source.
// loop thru the main array and slice it based on indexes
for(index, number) in array.enumerated() {
if 0...2 ~= index { // if in range
arr2.append(number)
} else
if index <= 5 {
arr3.append(number)
} else
if index <= 8 {
arr4.append(number)
} else
if index <= 11 {
arr5.append(number)
}
}
Finally : in your numberOfItemsInSection check the UICollectionView and set return its data source like,
if collectionView = myMainCollectionView {
return arr3.count
}
And goes the same for the cellForItemAt
Heads Up : make sure your dataSource arrays are empty initially,
let arr2: [Int] = [] {
didSet{
//reload your collectionView
}
}