Delete button not working, collectionView

Question

I have a collectionView with 3 sections and a button on the header to delete each section. I wrote my code but I keep getting this error:

fatal error: Index out of range (lldb)

But I'm not sure what is going on? Why isn't it working.

This is my code:

//Global Identifier
private let cellIdentifier = "ImageCell"
private let headerIdentifier = "Header"


class ViewController: UICollectionViewController {

//Data Models

//Image Arrays
var fireImages: [UIImage] = [
    UIImage(named: "charizard")!,
    UIImage(named: "ninetails")!,
    UIImage(named: "arcanine")!,
    UIImage(named: "rapidash")!,
    UIImage(named: "magmar")!,
    UIImage(named: "flareon")!
]

var waterImages: [UIImage] = [
    UIImage(named: "blastoise")!,
    UIImage(named: "golduck")!,
    UIImage(named: "cloyster")!,
    UIImage(named: "goldeen")!,
    UIImage(named: "magikarp")!,
    UIImage(named: "vaporeon")!
]

var electricImages: [UIImage] = [
    UIImage(named: "pikachu")!,
    UIImage(named: "magneton")!,
    UIImage(named: "zapdos")!,
    UIImage(named: "electabuzz")!,
    UIImage(named: "raichu")!,
    UIImage(named: "jolteon")!
]

//Name Arrays
var fireNames = ["Charizard", "Ninetales", "Arcanine", "Rapidash", "Magmar", "Flareon"]

var waterNames = ["Blastoise", "Golduck", "Cloyster", "Goldeen", "Magikarp", "Vaporeon"]

var electricNames = ["Pikachu", "Magneton", "Zapdos", "Electrabuzz", "Raichu", "Jolteon"]

//Sections
var sectionTitle = ["Fire Types", "Water Types", "Electric Types"]


//--------------------------------

    override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.
}

    override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

//--------------------------------


//MARK: - UICollectionViewDataSource

//Number of Sections
override func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    return sectionTitle.count
}

//Number of Cells in each Section
override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
//How can I dynamically code this area?
    return 6
}

//Header Configuration
override func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView {

    if indexPath.section == 0 {

        //Fire Type header
    let header = collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader, withReuseIdentifier: headerIdentifier, forIndexPath: indexPath) as! CollectionReusableView

        header.headerTitle.text = sectionTitle[indexPath.section]
        header.backgroundColor = UIColor.orangeColor()
        header.deleteButton.tag = indexPath.section

         return header

    } else if indexPath.section == 1 {

        //Water Type header
        let header = collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader, withReuseIdentifier: headerIdentifier, forIndexPath: indexPath) as! CollectionReusableView

        header.headerTitle.text = sectionTitle[indexPath.section]
        header.backgroundColor = UIColor.cyanColor()
        header.deleteButton.tag = indexPath.section

        return header

    } else {

        //Electric Type header
        let header = collectionView.dequeueReusableSupplementaryViewOfKind(UICollectionElementKindSectionHeader, withReuseIdentifier: headerIdentifier, forIndexPath: indexPath) as! CollectionReusableView

        header.headerTitle.text = sectionTitle[indexPath.section]
        header.backgroundColor = UIColor.yellowColor()
        header.deleteButton.tag = indexPath.section

        return header

    }

}

//Cell Configuration
override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    if indexPath.section == 0 {

        //Fire Type cells
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellIdentifier, forIndexPath: indexPath) as! CollectionViewCell

        cell.pokemonImage.image = fireImages[indexPath.row]
        cell.pokemonLabel.text = fireNames[indexPath.row]


    return cell

    } else if indexPath.section == 1 {

        //Water Type cells
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellIdentifier, forIndexPath: indexPath) as! CollectionViewCell

        cell.pokemonImage.image = waterImages[indexPath.row]
        cell.pokemonLabel.text = waterNames[indexPath.row]

        return cell

    } else {

        //Electric Type cells
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(cellIdentifier, forIndexPath: indexPath) as! CollectionViewCell

        cell.pokemonImage.image = electricImages[indexPath.row]
        cell.pokemonLabel.text = electricNames[indexPath.row]

        return cell

    }

}

//Delete Section Button
@IBAction func deleteSectionButton(sender: UIButton) {

    //Section tag
    let section = sender.tag

    if section == 0 {

    //Update data model
    fireImages.removeAtIndex(section)
    fireNames.removeAtIndex(section)
    sectionTitle.removeAtIndex(section)

    //Action
    collectionView?.performBatchUpdates({
        self.collectionView?.deleteSections(NSIndexSet(index: section))
        },
        completion: { (finished) in
            if finished {
                self.collectionView!.reloadData()
            }
        })

    } else if section == 1 {

        //Update data model
        waterImages.removeAtIndex(section)
        waterNames.removeAtIndex(section)
        sectionTitle.removeAtIndex(section)

        //Action
        collectionView?.performBatchUpdates({
            self.collectionView?.deleteSections(NSIndexSet(index: section))
            },
            completion: { (finished) in
                if finished {
                    self.collectionView!.reloadData()
                }
        })

    } else {

        //Update data model
        electricImages.removeAtIndex(section)
        electricNames.removeAtIndex(section)
        sectionTitle.removeAtIndex(section)

        //Action
        collectionView?.performBatchUpdates({
            self.collectionView?.deleteSections(NSIndexSet(index: section))
            },
            completion: { (finished) in
            if finished {
                self.collectionView!.reloadData()
            }
        })

    }

}

}

It's also showing me this.

Answer 1

First of all, your code is nothing like Object-oriented. Here are some problems:

1. You have hard-coded number of cells in a section: 6. How will you handle the case pokemon class types have different number of pokemons?
2. Your code has many duplications that must be avoided. There are lots of if section == controls; which is a clear indicator of avoiding OO principles.

Anyway; since you have much bigger problems than non-working delete button; I have decided to set up a clean project for you to illustrate how to approach the problem in a more Object-oriented way. I have created domain entities such as Pokemon, and PokemonClass and stored corresponding attributes inside these entities. By this way; I have avoided many code duplication existing in your controller class. I have also illustrated you how to get delete button working (By the way; there sure are better ways to handle this deleting a section functionality; but I don't have enough time to search for it and I did it the first way that comes to my mind). I did not deal with images of the pokemons again due to time limitations. Anyway; look at the source code I have shared at my github repository. You can ask any questions you have and you are of course free to use any code I have provided. Hope this will help you getting started to design in an OO way.