I'm using IGListKit to show images vertically and horizontally. That's why I used
nested adapter approach to have horizontally scrolling collectionViews inside a vertically scrolling collectionView. But when having many images/items it starts to lag every time a new row is being displayed. The scrolling stops for a few milliseconds and then goes on.
I have set a level and button in vertical collection views (first adapter). Inside every vertical Collection view, I have created another adapter to show images.
Help me to solve this lagging issue.
Full project link: https://github.com/sagarthecoder/IGListKit-Dummy-Project
This is my partial code from ViewController.swift file
class ViewController: UIViewController {
@IBOutlet weak var collectionView: UICollectionView!
lazy var adapter : ListAdapter = {
return ListAdapter(updater: ListAdapterUpdater(), viewController: self, workingRangeSize: 0)
}()
override func viewDidLoad() {
super.viewDidLoad()
adapter.collectionView = collectionView
adapter.dataSource = self
}
}
extension ViewController : ListAdapterDataSource {
func objects(for listAdapter: ListAdapter) -> [ListDiffable] {
return someItems;
}
func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -> ListSectionController {
return RootSectionController()
}
}
This is my partial code from RootSectionController.swift file where I add another adapter
class RootSectionController: ListSectionController{
var header : Header! // Items that came from ViewController
lazy var adapter: ListAdapter = {
let adapter = ListAdapter(updater: ListAdapterUpdater(),
viewController: self.viewController)
adapter.dataSource = self
return adapter
}()
}
extension RootSectionController {
override func cellForItem(at index: Int) -> UICollectionViewCell {
let cell : RootCollectionViewCell = (collectionContext?.dequeueReusableCell(withNibName: "RootCollectionViewCell", bundle: nil, for: self, at: index)) as! RootCollectionViewCell
cell.categoryName.text = header.categoryName
adapter.collectionView = cell.collectionView
return cell
}
override func didUpdate(to object: Any) {
header = object as? Header
}
}
extension RootSectionController : ListAdapterDataSource {
func objects(for listAdapter: ListAdapter) -> [ListDiffable] {
return someItems
}
func listAdapter(_ listAdapter: ListAdapter, sectionControllerFor object: Any) -> ListSectionController {
return UserSectionController()
}
}
This is my partial code from User.Swift file
class User: NSObject {
let id : Int
let name: String
let imageName : String
}
extension User: ListDiffable {
func diffIdentifier() -> NSObjectProtocol {
return id as NSObjectProtocol
}
func isEqual(toDiffableObject object: ListDiffable?) -> Bool {
if (object as? User) != nil {
return true
} else {
return false
}
}
}
This is my Header.swift file
class Header: NSObject {
let categoryName : String
}
extension Header : ListDiffable {
func diffIdentifier() -> NSObjectProtocol {
return categoryName as NSObjectProtocol
}
func isEqual(toDiffableObject object: ListDiffable?) -> Bool {
if let object = object as? Header {
return categoryName == object.categoryName
} else {
return false
}
}
}