Out of index range when grab string from array in collection view - arrays

Question

I want my app to show data from mysql database in collectionview so i write down the mysql connection code in viewDidload() and make it in array format everything work fine except for showing data in collectionview Here is my code
var subjectlist = ""
var imgurllist = ""
var subjectarray = [String]()
var imgurllistarray = [String]()
override func viewDidLoad() {
super.viewDidLoad()
collectionview.dataSource = self
collectionview.delegate = self
let request = NSMutableURLRequest(url: NSURL(string: [Point to file on my server])! as URL)
let urlsession = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: {data, response, error -> Void in
DispatchQueue.main.async {
do {
if let dataunwarp = data {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
if let parseJSON = json {
if let subjectnotfound = parseJSON["subjectnotfound"]{
let alert = UIAlertController(title: "เกิดข้อผิดพลาด", message: "ไม่พบ subject ในเซิฟเวอร์ กรุณาลองใหม่อีกครั้ง", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "ปิด", style: .default, handler: { (alert: UIAlertAction!) in
self.navigationController?.popViewController(animated: true)
}))
self.dismiss(animated: false, completion: { () in self.present(alert, animated: true, completion: nil) })
} else {
self.subjectlist = parseJSON["subjectlist"] as! String
self.imgurllist = parseJSON["imgurllist"] as! String
self.subjectarray = Array(self.subjectlist.components(separatedBy: ","))
print("subjectarray=\(self.subjectarray)")
print(self.subjectarray[0])
//self.imgurllistarray = Array(self.imgurllist.components(separatedBy: ","))
}
} else {
let alert = UIAlertController(title: "เกิดข้อผิดพลาด", message: "เกิดข้อผิดพลาดจากเซิฟเวอร์", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "ปิด", style: .default, handler: { (alert: UIAlertAction!) in
self.navigationController?.popViewController(animated: true)
}))
self.dismiss(animated: false, completion: { () in self.present(alert, animated: true, completion: nil) })
}
} else {
let alert = UIAlertController(title: "เกิดข้อผิดพลาด", message: "เกิดข้อผิดพลาดจากเซิฟเวอร์", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "ปิด", style: .default, handler: { (alert: UIAlertAction!) in
self.navigationController?.popViewController(animated: true)
}))
self.dismiss(animated: false, completion: { () in self.present(alert, animated: true, completion: nil) })
}
} catch {
let alert = UIAlertController(title: "เกิดข้อผิดพลาด", message: "ไม่สามารถติดต่อกับเซิฟเวอร์ได้ กรุณาตรวจสอบการเชื่อมต่ออินเตอร์เน็ตเเละลองใหม่อีกครั้ง", preferredStyle: .alert)
alert.addAction(UIAlertAction(title: "ปิด", style: .default, handler: { (alert: UIAlertAction!) in
self.navigationController?.popViewController(animated: true)
}))
self.dismiss(animated: false, completion: { () in self.present(alert, animated: true, completion: nil) })
}
}})
urlsession.resume()
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return subject.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Cell", for: indexPath) as! collectionviewcell
let subjectimgurl = NSMutableURLRequest(url: NSURL(string: "https://psmapps.com/psmatstamp/images/atstamp.png")! as URL)
let imgsession = URLSession.shared.dataTask(with: subjectimgurl as URLRequest, completionHandler: {data, response, error -> Void in
if let e = error {
print("Error downloading picture: \(e)")
} else {
// No errors found.
// It would be weird if we didn't have a response, so check for that too.
if let res = response as? HTTPURLResponse {
if let imageData = data {
// Finally convert that Data into an image and do what you wish with it.
let subjectimg = UIImage(data: imageData)
DispatchQueue.main.async {
cell.subjectimage.image = subjectimg
}
} else {
print("Couldn't get image: Image is nil")
}
} else {
print("Couldn't get response code for some reason")
}
}
})
imgsession.resume()
cell.subjectlabel.text = subjectarray[indexPath.item]
print(self.subjectarray[indexPath.item])
cell.layer.borderColor = UIColor.lightGray.cgColor
cell.layer.borderWidth = 0.5
return cell
}
An error occurred in this line before this view presented
cell.subjectlabel.text = subjectarray[indexPath.item]
with error message: "Index out of range" but when i uncomment the line that error occurred and print out the data from subjectarray, i can see my data with array type
How can i fix this problem?

Answer 1

Inside numberOfItemsInSection
return subject.count
Then inside cellForItemAt you use
subjectarray[indexPath.item]
Is there a guarantee that both will be same size at a time , also use SDWebImage to load images
Also after you get the data reload
self.subjectarray = Array(self.subjectlist.components(separatedBy: ","))
self.collectionView.reloadData()
plus spreading UIAlertController everywhere isn't a good way for compact code , consider making an extension / function and call it with the appropriate message