ScrollView that deletes image in based on location - ios

Question

I have made a scrollview, and made an array of images (which I will later add an option for the user to post images into that array and friends images will fill into that array) and want to have the user be able to see a photo and it tracks it.
I have created a for loop that added photos into the array, but when I created an if statement to take out an item in the array, I got an error because I would remove the image[i] from the array and I kinda know why this is happening, but want to fix it. So basically I need to take out an image in the array. Please help me out I'm still learning.
class ViewController: UIViewController {
var imageArray = [UIImage]()
#IBOutlet weak var mainScrollView: UIScrollView!
override func viewDidLoad() {
super.viewDidLoad()
mainScrollView.frame = view.frame
imageArray = [#imageLiteral(resourceName: "dubai6"), #imageLiteral(resourceName: "dubai2"), #imageLiteral(resourceName: "dubai7"), #imageLiteral(resourceName: "dubai4"), #imageLiteral(resourceName: "dubai3"), #imageLiteral(resourceName: "dubai5"), #imageLiteral(resourceName: "DigitalDrawingPreview"), #imageLiteral(resourceName: "denarus"), #imageLiteral(resourceName: "dubai1")]
for i in 0..<imageArray.count {
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFit
imageView.image = imageArray[i]
let xPosition = self.view.frame.width * CGFloat(i)
imageView.frame = CGRect(x: xPosition, y: 0, width: self.view.frame.width, height: self.mainScrollView.frame.height)
mainScrollView.contentSize.width = mainScrollView.frame.width * CGFloat(i + 1)
mainScrollView.addSubview(imageView)
}
for i in 0..<imageArray.count {
if (i >= 2) {
imageArray.remove(at: (i - 2))
}
}
// 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.
}
}
Thank you fellow better programmers.

Answer 1

You can't remove an element from a array while traversing it so you had to use a temp array
class ViewController: UIViewController {
var imageArray = [UIImage]()
#IBOutlet weak var mainScrollView: UIScrollView!
override func viewDidLoad() {
super.viewDidLoad()
mainScrollView.frame = view.frame
imageArray = [#imageLiteral(resourceName: "dubai6"), #imageLiteral(resourceName: "dubai2"), #imageLiteral(resourceName: "dubai7"), #imageLiteral(resourceName: "dubai4"), #imageLiteral(resourceName: "dubai3"), #imageLiteral(resourceName: "dubai5"), #imageLiteral(resourceName: "DigitalDrawingPreview"), #imageLiteral(resourceName: "denarus"), #imageLiteral(resourceName: "dubai1")]
for i in 0..<imageArray.count {
let imageView = UIImageView()
imageView.contentMode = .scaleAspectFit
imageView.image = imageArray[i]
let xPosition = self.view.frame.width * CGFloat(i)
imageView.frame = CGRect(x: xPosition, y: 0, width: self.view.frame.width, height: self.mainScrollView.frame.height)
mainScrollView.contentSize.width = mainScrollView.frame.width * CGFloat(i + 1)
mainScrollView.addSubview(imageView)
}
let tempArr = imageArray
for i in 0..<tempArr.count {
if (i >= 2) { // Breakpoint here
imageArray.remove(at: (i - 2))
}
}
// 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.
}
}
use step over to go through each line of for loop until it crashes and then print the value of i at that time by hovering cursor over it or type command at console po i and enter