Collection view auto resizing and setup repeating background - ios

Question

I am using collection view to load data from API. Here i want to extend size of collection view height instead of scrolling inside collection view. And also need to repeat the background image according to collection view height.
Here is the android layout and i want to develop similar to this.Tap here
import UIKit
import Nuke
import SVProgressHUD
import JSONJoy
class HomeViewController: UIViewController {
#IBOutlet weak var categoryCollection: UICollectionView!
#IBOutlet weak var tabbar: UITabBar!
var sectors:[Sector] = []
var timer = Timer()
var counter = 0
var selectedSector = ""
var selectedSectorName = ""
var webService = ApiService()
let plist = PlistHelper()
override func viewDidLoad() {
super.viewDidLoad()
self.categoryCollection.dataSource = self
self.categoryCollection.delegate = self
for item in tabbar.items ?? []{
item.image = item.image?.withRenderingMode(.alwaysOriginal)
}
UITabBarItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.white], for: .normal)
UITabBarItem.appearance().setTitleTextAttributes([NSAttributedString.Key.foregroundColor: UIColor.black], for: .selected)
listSectors()
self.categoryCollection.backgroundColor = UIColor(patternImage: UIImage(named: "bg")!)
}
override func viewWillAppear(_ animated: Bool) {
listbanners()
}
override func viewWillDisappear(_ animated: Bool) {
self.timer.invalidate()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "sectors"){
let vc = segue.destination as! SectorsViewController
vc.sectorCode = selectedSector
vc.sectorName = selectedSectorName
}
}
func listSectors(){
webService.listSectors({ (sectors, message, status) in
if(status){
if let resData = sectors.arrayObject {
do{
for data in resData{
self.sectors.append(try Sector(JSONLoader(data)))
}
DispatchQueue.main.async {
self.categoryCollection.reloadData()
}
}
catch let error {
print("JSonJoyError:\(error)")
}
}
}
})
}
}
extension HomeViewController: UICollectionViewDelegate, UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if(collectionView == bannerCollection){
return banners.count
}
else {
return sectors.count
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let options = ImageLoadingOptions(placeholder: UIImage(named: "bannerPlaceholder"),transition: .fadeIn(duration: 0.33))
if(collectionView == bannerCollection){
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! DataCollectionViewCell
Nuke.loadImage(with: URL(string: banners[indexPath.row].ImageUrl ?? "")!, options: options, into:cell.img)
return cell
}
else{
let cell = categoryCollection.dequeueReusableCell(withReuseIdentifier: "catCell", for: indexPath) as! catogeryCollectionViewCell
Nuke.loadImage(with: URL(string: sectors[indexPath.row].ImageUrl ?? "")!, options: options, into:cell.photoImageView)
return cell
}
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
if(collectionView == categoryCollection){
selectedSector = sectors[indexPath.row].Code ?? "FOOD"
selectedSectorName = sectors[indexPath.row].Name ?? "FOOD"
self.performSegue(withIdentifier: "sectors", sender: self)
}
}
}
extension HomeViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
return UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
if(collectionView == bannerCollection){
let size = bannerCollection.frame.size
return CGSize(width: size.width, height: size.height - 10)
}
else{
let size = categoryCollection.frame.size
print("size\(size)")
return CGSize(width: (size.width / 2) - 8, height:120)
}
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 30
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return 0.0
}
}

Answer 1

Following steps can help you to increase your collection View height according to data.
Create Heightconstraint outlet.
After loading data in collection view with delay of 0.2 sec in main thread,
Set Height Constraint constant = collection view content size height.