Passing data from CollectionVewCell to another view controller - swift

Question

Let's say we have CollectionViewController with Cells
So, my goal is to send the data from the active CollectionViewControllerCell (let's say i want to pass the category name) to another controller after click action on that CELL. So, how can i pass data from
import UIKit
class CategoriesViewController: UIViewController {
#IBOutlet weak var collectionView: UICollectionView!
var activeCategoryItemTitle:String = ""
var categories = Category.fetchCategories()
let cellScale: CGFloat = 0.7
override func viewDidLoad() {
super.viewDidLoad()
let screenSize = UIScreen.main.bounds.size
let cellWidth = floor(screenSize.width * cellScale)
let cellHeight = floor(screenSize.height * cellScale)
let insetX = (view.bounds.width - cellWidth) / 2
let insetY = (view.bounds.height - cellHeight) / 2
let layout = collectionView!.collectionViewLayout as! UICollectionViewFlowLayout
layout.itemSize = CGSize(width:cellWidth,height:cellHeight)
// collectionView.contentInset = UIEdgeInsets(top:insetY,left:insetX,bottom:insetY,right:insetX)
print(insetY)
collectionView.dataSource = self
collectionView.delegate = self
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destinationVC: ProductsViewController = segue.destination as! ProductsViewController
destinationVC.titleOfCategory = self.activeCategoryItemTitle
// let product = ProductsViewController()
// product.titleOfCategory = "asd"
}
}
// MARK UICollectionViewDataSource
extension CategoriesViewController:
UICollectionViewDataSource
{
func numberOfSections(in collectionView: UICollectionView) ->
Int {
return 1
}
func collectionView(_ collectionView: UICollectionView,numberOfItemsInSection section: Int) -> Int {
return categories.count
}
func collectionView(_ collectionView: UICollectionView,cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell =
collectionView.dequeueReusableCell(withReuseIdentifier: "CategoriesCollectionViewCell",for:indexPath) as!
CategoriesCollectionViewCell
let category = categories[indexPath.item]
cell.category = category
return cell
}
}
extension CategoriesViewController: UIScrollViewDelegate, UICollectionViewDelegate
{
func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
let layout = self.collectionView?.collectionViewLayout as! UICollectionViewFlowLayout
let cellWidthincludingSpacing = layout.itemSize.width+layout.minimumLineSpacing
var offset = targetContentOffset.pointee
let index = (offset.x + scrollView.contentInset.left) / cellWidthincludingSpacing
let roundedIndex = round(index)
offset = CGPoint(x: roundedIndex*cellWidthincludingSpacing-scrollView.contentInset.left, y: scrollView.contentInset.top)
targetContentOffset.pointee = offset
}
}
and second one is my products list controller, that must receive category name and put inside view
//
import UIKit
class ProductsViewController: UIViewController {
#IBOutlet weak var categoryTitle: UILabel!
var titleOfCategory:String = ""
#IBOutlet weak var collectionView: UICollectionView!
var products = Product.fetchProducts()
// let cellScale: CGFloat = 0.63
override func viewDidLoad() {
super.viewDidLoad()
categoryTitle.text = titleOfCategory
// let screenSize = UIScreen.main.bounds.size
// let cellWidth = floor(screenSize.width * cellScale)
// let cellHeight = floor(screenSize.height * cellScale)
// let insetX = (view.bounds.width - cellWidth) / 2
// let insetY = (view.bounds.height - cellHeight) / 2
// let layout = collectionView!.collectionViewLayout as! UICollectionViewFlowLayout
// layout.itemSize = CGSize(width:cellWidth,height:cellHeight)
// collectionView.contentInset = UIEdgeInsets(top:insetY,left:insetX,bottom:insetY,right:insetX)
// collectionView.dataSource = self
// collectionView.delegate = self
}
}
// MARK UICollectionViewDataSource
extension ProductsViewController:
UICollectionViewDataSource
{
func numberOfSections(in collectionView: UICollectionView) ->
Int {
return 1
}
func collectionView(_ collectionView: UICollectionView,numberOfItemsInSection section: Int) -> Int {
return products.count
}
func collectionView(_ collectionView: UICollectionView,cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell =
collectionView.dequeueReusableCell(withReuseIdentifier: "ProductsCollectionViewCell",for:indexPath) as!
ProductsCollectionViewCell
let product = products[indexPath.item]
cell.product = product
return cell
}
}
extension ProductsViewController: UIScrollViewDelegate, UICollectionViewDelegate
{
func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
let layout = self.collectionView?.collectionViewLayout as! UICollectionViewFlowLayout
let cellWidthincludingSpacing = layout.itemSize.width+layout.minimumLineSpacing
var offset = targetContentOffset.pointee
let index = (offset.x + scrollView.contentInset.left) / cellWidthincludingSpacing
let roundedIndex = round(index)
offset = CGPoint(x: roundedIndex*cellWidthincludingSpacing-scrollView.contentInset.left, y: scrollView.contentInset.top)
targetContentOffset.pointee = offset
}
}

Answer 1

1, add didSelectItemAt to your collectionView, this will handle the click on the cell.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
performSegue(withIdentifier: "showProducts", sender: categories[indexPath.item])
}
2, In your CategoriesViewController start type "prepare" and you will see the prepare for segue method.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showProducts" {
let destination = segue.destination as! ProductsViewController
destination.titleOfCategory = sender as? String
}
}