Error on Performing Segue with UICollectionView - ios

Question

When I click on any UICollectionView item, I got this error on PerformSegue line:
Thread 1: Fatal error: Index out of range
However, the compiler don't read the function and simply jumps straight to the PerformSegue, so I end up out of index. How can I fix that? When the user clicks on any UICollectionView index, I gotta replace the Indexpath in the function parameter and repeat the process.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
getCategoriaPorID(IdCategoria: indexPath.row) { (data) in
DispatchQueue.main.async {
self.dataCategoriaID = data
}
}
performSegue(withIdentifier: "segueCategorias", sender:self.dataCategoriaID[indexPath.row])
}
Complete ViewController file:
import UIKit
class ViewController: UIViewController, UICollectionViewDataSource, UITableViewDataSource, UITableViewDelegate, UICollectionViewDelegate {
#IBOutlet weak var tableViewTopSell: UITableView!
#IBOutlet var collectionView: UICollectionView!
#IBOutlet weak var collectionViewBanner: UICollectionView!
var indexPathId = Int()
var dataSource: [Content] = [Content]()
var dataBanner: [Banner] = [Banner]()
var dataTopSold: [Top10] = [Top10]()
var dataCategoriaID: [CategoriaIDItems] = [CategoriaIDItems]()
override func viewDidLoad() {
super.viewDidLoad()
//Delegate TableView
self.tableViewTopSell.delegate = self
//SetupNavBarCustom
self.navigationController?.navigationBar.CustomNavigationBar()
let logo = UIImage(named: "tag.png")
let imageView = UIImageView(image:logo)
self.navigationItem.titleView = imageView
//CallAPIData
getTopSold { (data) in
DispatchQueue.main.async {
self.dataTopSold = data
self.tableViewTopSell.reloadData()
}
}
getBanner { (data) in
DispatchQueue.main.async {
self.dataBanner = data
self.collectionViewBanner.reloadData()
}
}
getAudiobooksAPI { (data) in
DispatchQueue.main.async {
self.dataSource = data
self.collectionView.reloadData()
}
}
}
//CollectionView
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if (collectionView == self.collectionView) {
return self.dataSource.count
}else{
return self.dataBanner.count
}}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if (collectionView == self.collectionView) {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionViewCell", for: indexPath) as! CollectionViewCell
let content = self.dataSource[indexPath.item]
cell.bookLabel.text = content.descricao
cell.bookImage.setImage(url: content.urlImagem, placeholder: "")
return cell
}else if (collectionView == self.collectionViewBanner) {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionViewCellBanner", for: indexPath) as! CollectionViewCell
let content = self.dataBanner[indexPath.item]
cell.bannerImage.setImage(url: content.urlImagem, placeholder: "")
return cell
}
return UICollectionViewCell()
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
getCategoriaPorID(IdCategoria: indexPath.row) { (data) in
DispatchQueue.main.async {
self.dataCategoriaID = data
}
}
performSegue(withIdentifier: "segueCategorias", sender:self.dataCategoriaID[indexPath.row])
}
//TableView
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.dataTopSold.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "topSoldCell", for: indexPath) as! TableViewCell
let content = self.dataTopSold[indexPath.row]
cell.labelNomeTopSell.text = content.nome
cell.imageViewTopSell.setImage(url: content.urlImagem, placeholder: "")
cell.labelPrecoDe.text = "R$ \(content.precoDe)"
//Colocar strike em cima do Preco Antigo
let oldPrice = "R$ \(content.precoDe)"
let promotionString = oldPrice + ""
let attributedStr = NSMutableAttributedString(string: promotionString)
let crossAttr = [NSAttributedStringKey.strikethroughStyle: NSUnderlineStyle.styleSingle.rawValue]
attributedStr.addAttributes(crossAttr, range: NSMakeRange(0, oldPrice.count))
cell.labelPrecoDe.attributedText = attributedStr
//
cell.labelPrecoPor.text = "R$ 119.99"
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "segueId", sender:self.dataTopSold[indexPath.row])
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "segueId" {
let des = segue.destination as? TelaDetalheProdutos
//.item possui uma propriedade instanciada na TelaDetalheProdutos
des?.item = (sender as? Top10)
//Segue para CollectionView Categorias
} else if segue.identifier == "segueCategorias" {
let desc = segue.destination as? TelaCategorias
desc?.item = (sender as? CategoriaIDItems)
}
}
}
//Cast UIImage Extension
extension UIImageView{
func setImage(url : String, placeholder: String, callback : (() -> Void)? = nil){
self.image = UIImage(named: "no-photo")
URLSession.shared.dataTask(with: NSURL(string: url)! as URL, completionHandler: { (data, response, error) -> Void in
guard error == nil else{
return
}
DispatchQueue.main.async(execute: { () -> Void in
let image = UIImage(data: data!)
self.image = image
if let callback = callback{
callback()
}
})
}).resume()
}
}

Answer 1

Use main thread only to update UI. The problem is you are setting dataCategoriaID on main thread I assume which is inside asynchronous network call function. So you are trying to perform segue before setting dataCategoriaID and that is the reason it is empty and throwing index out of range error.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
getCategoriaPorID(IdCategoria: indexPath.row) { (data) in
self.dataCategoriaID = data
performSegue(withIdentifier: "segueCategorias", sender:self.dataCategoriaID[indexPath.row])
}
}