I am trying to make a app that when you click the button on collectionview cell, you can show the detail viewcontroller and gives more information about your choice.But all attributes of my struct shown as nil on other viewController.

Here is my ViewController including CollectionView

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var collectionView: UICollectionView!
    var ilceDizisi = [Ilceler]()
    var secim : Ilceler?
    override func viewDidLoad() {
        super.viewDidLoad()
        collectionView.delegate = self
        collectionView.dataSource = self
        let textAttributes = [NSAttributedString.Key.foregroundColor:UIColor.white, NSAttributedString.Key.font:UIFont(name: "Papyrus", size: 25.0)]
        navigationController?.navigationBar.titleTextAttributes = textAttributes as [NSAttributedString.Key : Any]
        //Hucre Boyurlandirmasi
        let tasarim = UICollectionViewFlowLayout()
        let genislik = self.collectionView.frame.size.width
        tasarim.minimumInteritemSpacing = 5
        tasarim.minimumLineSpacing = 5
        tasarim.sectionInset = UIEdgeInsets(top: 10, left: 10, bottom: 10, right: 10)
        tasarim.itemSize = CGSize(width: (genislik - 30) / 2, height: 322.0)
        collectionView.collectionViewLayout = tasarim
        ilceDizisi = [Ilceler.adalar, Ilceler.arnavutkoy, Ilceler.atasehir, Ilceler.avcilar, Ilceler.bagciler, Ilceler.bahcelievler, Ilceler.bakirkoy, Ilceler.basaksehir, Ilceler.bayrampasa, Ilceler.besiktas, Ilceler.beykoz, Ilceler.beylikduzu , Ilceler.beyoglu, Ilceler.buyukcekmece, Ilceler.catalca , Ilceler.cekmekoy , Ilceler.esenler , Ilceler.esenyurt , Ilceler.eyupsultan , Ilceler.fatih , Ilceler.gaziosmanpasa , Ilceler.gungoren , Ilceler.kadikoy , Ilceler.kagithane , Ilceler.kartal, Ilceler.kucukcekmece , Ilceler.maltepe , Ilceler.pendik , Ilceler.sancaktepe , Ilceler.sariyer , Ilceler.sile , Ilceler.sultanbeyli , Ilceler.sultangazi , Ilceler.sile, Ilceler.sisli , Ilceler.tuzla , Ilceler.umraniye , Ilceler.uskudar , Ilceler.zeytinburnu]
  
    }


}



extension ViewController : UICollectionViewDelegate , UICollectionViewDataSource, CellButton {
    
    func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 1
    }
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return ilceDizisi.count
    }
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "hucre", for: indexPath) as! Cell
        cell.isimLabel.text = ilceDizisi[indexPath.row].isim!
        cell.yakaLabel.text = ilceDizisi[indexPath.row].yaka!
        cell.ilceGorsel.image = UIImage(named: ilceDizisi[indexPath.row].gorsel!)
        cell.prot = self
        cell.indexPath = indexPath
        return cell
    }
    func detail(indexPath: IndexPath) {
        performSegue(withIdentifier: "toDetailVC", sender: nil)
        secim = ilceDizisi[indexPath.row]
        
        
        
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "toDetailVC" {
            let destVC = segue.destination as! DetailViewController
            destVC.secilenIlce = secim
        }
    }
    
}

Here is my detail viewController

import UIKit

class DetailViewController: UIViewController {

    @IBOutlet weak var baskan: UILabel!
    @IBOutlet weak var yuz: UILabel!
    @IBOutlet weak var nufus: UILabel!
    @IBOutlet weak var yaka: UILabel!
    @IBOutlet weak var gorselView: UIImageView!
    @IBOutlet weak var ilceLabel: UILabel!
    var secilenIlce : Ilceler?
    override func viewDidLoad() {
        super.viewDidLoad()
        baskan.text = "Belediye Başkanı : \(secilenIlce?.belediyeBaskani)"
        yuz.text = "Yüzölçümü(km²) : \(secilenIlce?.yuzolcumu)"
        nufus.text = "Nüfus : \(secilenIlce?.nufus)"
        yaka.text = "Bulunduğu Yaka : \(secilenIlce?.yaka)"
        gorselView.image = UIImage(named: (secilenIlce?.gorsel)!)
        ilceLabel.text = secilenIlce?.isim    
    }
}

I want to see informations like this

but when i runned the project

I tried to get all informations with prepareforsegue func.Actually i needed to delete imageview.image code due to the fact that it returns nil and my project crashs if i unwrapped it.What is my fault and how can i fix it

CodePudding user response：

You need to set secim before performing the segue. Swap the two lines in your detail function.

func detail(indexPath: IndexPath) {
    secim = ilceDizisi[indexPath.row]
    performSegue(withIdentifier: "toDetailVC", sender: nil)
}

With your original code you were calling performSeque which results in the call to prepare. But at that point you haven't set secim. So you were setting secim after prepare was being called. Most likely, if you tapped on a cell again, it would then show the data of the previously tapped cell.