UICollectionView Lag/frame drop - ios

Question

Good afternoon all my app is currently dropping frames and i am not sure how to fix it...im a bit lost.
hopefully you guys/gals can point me in the right direction.
I am currently using Kingfisher to download the images from my backend, everything works well with the exception of the scrolling it's a bit choppy when you scroll down.
the controller code is as followed maybe there's something wrong with it.
i am using storyboard and have removed and added the constraints...but ive had no luck.
import UIKit
import Kingfisher
class WallpaperCVC: UICollectionViewController , UIViewControllerTransitioningDelegate {
var categoryId: String!
var categoryName: String!
var wallpaperBackend: Backend!
var result:CGSize!
// Header peralax
fileprivate let headerId = "headerId"
fileprivate let padding: CGFloat = 16
#IBOutlet var wpMain: UICollectionView!
override func viewDidLoad() {
super.viewDidLoad()
self.title = self.categoryName // Name to the controller or section selected
// go go gadget data...
getData()
buttonGray()
setupCollectionViewLayout()
setupCollectionView()
}
func getData(){
GLOBAL_BACKEND_DATA.removeAll()
self.wallpaperBackend = Backend()
self.wallpaperBackend.getWallByIdData(id: self.categoryId) { (god) in
for post in god {
let postData = post as! NSDictionary
let wallpaperCVCId = postData.value(forKey: "id") as! String
let wallpaperCVCFile = postData.value(forKey: "file") as! String
let wallpaperCVCCategory = postData.value(forKey: "category") as! String
let wallpaperCVCDownload = Int(postData.value(forKey: "download") as! String)
GLOBAL_BACKEND_DATA.append(WallpaperModel(wallpaperModelId: wallpaperCVCId, wallpaperModelFile: wallpaperCVCFile, wallpaperModelCategoryId: wallpaperCVCCategory, wallpaperModelDownload: wallpaperCVCDownload!))
}
self.collectionView?.reloadData()
}
}
#IBAction func pressedAction(_ sender: UIButton) {
// do your stuff here
self.dismiss(animated: true, completion: nil)
print("you clicked on button \(sender.tag)")
}
func buttonGray(){
let myButton = UIButton() // if you want to set the type use like UIButton(type: .RoundedRect) or UIButton(type: .Custom)
let img = UIImage(named: "buttonA")
myButton.setImage(img, for: .normal)
// myButton.setTitleColor(UIColor.blue, for: .normal)
myButton.frame = CGRect(x: 15, y: 50, width: 100, height: 100)
// shadow
myButton.layer.shadowOpacity = 0.5
myButton.layer.shadowRadius = 4
myButton.layer.shadowOffset = CGSize(width: 0, height: 5)
myButton.addTarget(self, action: #selector(pressedAction(_:)), for: .touchUpInside)
// haptic feedback
myButton.isHaptic = true
myButton.hapticType = .impact(.medium)
//floatbutton like this
view.addSubview(myButton)
myButton.translatesAutoresizingMaskIntoConstraints = false
myButton.leftAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leftAnchor, constant: 10).isActive = true
myButton.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor, constant: 0).isActive = true
}
// MARK: UICollectionViewDataSource
override func numberOfSections(in collectionView: UICollectionView) -> Int {
// You only need one section for now
return 1
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
// Here call the wallpapers
return GLOBAL_BACKEND_DATA.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
// pulling & going to the controller
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "wallpapers", for: indexPath) as! WallpaperCVCell
let godData = GLOBAL_BACKEND_DATA[indexPath.row]
let imageURL = String(format:"%#uploads/image/%#", BASE_BACKEND_URL,godData.wallpaperModelFile) // calling wallpaperModel controller
let escapedURL = imageURL.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
let urls = URL(string:escapedURL!)
// if nothing load this...
let loadImage = UIImage(named: "skullLoading")
cell.collWallpaperImage.kf.setImage(with: urls, placeholder: loadImage)
cell.collWallpaperImage.kf.indicatorType = .activity // Showing a loading indicator while downloading
// lets count the downloads
let count = godData.wallpaperModelDownload as Int // calling wallpaperModel controller
cell.collectionCount.text = String(count) //collection view cell count label
cell.configure() // calling a function from the cell
return cell
}
// Lets move over to the next controller
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
print("Tapped....Tapped go to the next controller..")
collectionView.deselectItem(at: indexPath, animated: true)
let vc = self.storyboard!.instantiateViewController(withIdentifier: "page") as! PageViewController
vc.position = indexPath.row
vc.categoryName = self.categoryName
vc.transitioningDelegate = self
vc.modalPresentationStyle = .custom
self.present(vc, animated: true, completion: nil)
}
}
// MARK: - CollectionView Delegate
extension WallpaperCVC {
// size images
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
result = CGSize(width: 187, height: 314)
if DeviceType.IS_IPHONE_5 {
result = CGSize(width: 160, height: 280)
}
if DeviceType.IS_IPHONE_6 {
result = CGSize(width: 187, height: 314)
}
if DeviceType.IS_IPHONE_6P {
result = CGSize(width: 207, height: 320)
}
if DeviceType.IS_IPHONE_4_OR_LESS {
result = CGSize(width: 151, height: 200)
}
return result;
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 15, left: 8, bottom: 5, right: 8)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 10
}
//size to all model screens to one.....NOW!!!!!!!!
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let width = UIScreen.main.bounds.width
return CGSize(width: (width - 28)/2, height: 350) // width & height are the same to make a square cell
}
}
// MARK: - CollectionView Layout Delegate
extension WallpaperCVC : UICollectionViewDelegateFlowLayout {
// Header peralax
fileprivate func setupCollectionViewLayout() {
let padding: CGFloat = 16
if let layout = wpMain.collectionViewLayout as? UICollectionViewFlowLayout {
layout.sectionInset = .init(top: padding, left: 0, bottom: padding, right: 0)
}
}
// Header peralax
fileprivate func setupCollectionView(){
wpMain.contentInsetAdjustmentBehavior = .never
wpMain.register(headerView.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: headerId)
}
// Header peralax
override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: headerId, for: indexPath)
return headerView
}
// Header peralax
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
return .init(width: view.frame.width, height: 400)
}
}
the cell looks like this
import UIKit
import Spring
import UICountingLabel
class WallpaperCVCell: UICollectionViewCell {
override func layoutSubviews() {
super.layoutSubviews()
// self.textLabel?.frame = self.bounds
}
func configure() {
layer.shouldRasterize = true
layer.rasterizationScale = UIScreen.main.scale
contentView.layer.cornerRadius = 7
contentView.layer.masksToBounds = true
// contentView.layer.borderWidth = 1.0
// contentView.layer.borderColor = UIColor.black.cgColor
}
#IBOutlet weak var collectionCount: UICountingLabel!
#IBOutlet weak var collWallpaperImage: UIImageView!
override func awakeFromNib() {
super.awakeFromNib()
}
}
&& here is the video...the initial scroll lags then it goes away but it does it everytime
iPhone app lag video
EDIT: Ok in the end i remode Kingfisher & installed SDWebImage this took care of the problem.

Answer 1

Based on the given code there is nothing that should cause the lag. If you could share a short video of the lag that might help understand the problem better.
And also if you could share the code that is in your cell.configure() method that would also help.
I do have a few suggestions for you that might help, you can try them on.
first of all you can move your device check
if DeviceType.IS_IPHONE_5 {
result = CGSize(width: 160, height: 280)
}
if DeviceType.IS_IPHONE_6 {
result = CGSize(width: 187, height: 314)
}
if DeviceType.IS_IPHONE_6P {
result = CGSize(width: 207, height: 320)
}
if DeviceType.IS_IPHONE_4_OR_LESS {
result = CGSize(width: 151, height: 200)
}
in viewDidLoad which will help your collection view layout to size your cells faster and not having to check this every time the user scrolls
Something like this
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
return result;
}
and
override func viewDidLoad() {
super.viewDidLoad()
self.title = self.categoryName // Name to the controller or section selected
setupDeviceSize()
// go go gadget data...
getData()
buttonGray()
setupCollectionViewLayout()
setupCollectionView()
}
func setupDeviceSize(){
if DeviceType.IS_IPHONE_5 {
result = CGSize(width: 160, height: 280)
}
if DeviceType.IS_IPHONE_6 {
result = CGSize(width: 187, height: 314)
}
if DeviceType.IS_IPHONE_6P {
result = CGSize(width: 207, height: 320)
}
if DeviceType.IS_IPHONE_4_OR_LESS {
result = CGSize(width: 151, height: 200)
}
}
Second is you can create a global variable for your place holder image
let loadImage = UIImage(named: "skullLoading")
and use that in your cellForItemAtIndexpath, which will again save loading of the placeholder image every time your cellForItemAtIndexpath is called.
You should always keep your cellForItemAtIndexpath as light as possible for a smooth scrolling experience.
Hope this helps.