Categorize DynamoDB fetched table data for collection view cells - ios

Question

I am working on a services app in which user creates a post whose details are saved in a dynamoDb table. I have fetched all the data in the table and now i want to display the data in collection view controller such that each cell represents single post. Now i am not sure how to segregate every single post from that data and provide it to collection view. My table fields are:
Table_Screenshot
My code is:
import UIKit
import AWSDynamoDB
class ProvidingViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {
#IBOutlet weak var PCV: UICollectionView!
let db = AWSDynamoDBObjectMapper.default()
let scanExpression = AWSDynamoDBScanExpression()
var counter:Int = 0
var imagex = ["UserIcon.png", "chat2.png","UserIcon.png", "delete.png","UserIcon.png", "delete.png","UserIcon.png", "delete.png","UserIcon.png", "delete.png","UserIcon.png", "delete.png"]
var images:[String] = []
override func viewDidLoad() {
super.viewDidLoad()
scanner()
}
///
func scanner(){
scanExpression.limit = 2000
db.scan(PostDetails.self, expression: scanExpression).continueWith(block: { (task:AWSTask!) -> AnyObject! in
if task.result != nil {
let paginatedOutput = task.result!
//use the results
for item in paginatedOutput.items as! [PostDetails] {
self.counter = paginatedOutput.items.count
self.images.append(item.userId!)
}
if ((task.error) != nil) {
print("Error: Could not fetch PostDetails table data")
}
return nil
}
return nil
})
}
///
func numberOfSections(in collectionView: UICollectionView) -> Int {
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return images.count
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = PCV.dequeueReusableCell(withReuseIdentifier: "c", for: indexPath) as! CellsCollectionViewCell
cell.ProvImage.image = UIImage(named: imagex[indexPath.row])
cell.ProvLabel.text = images[indexPath.row]
return cell
}
}
I have images array in which i am fetching data. When i print out the array it has data but when i assign it to collection view controller, screen is displayed empty i.e no cells. Please help. Thanks

Answer 1

The real issue you are facing is that when View loads the images array is empty and CollectionView loads empty and when you are loading images in the array in the scanner method you are not calling reloadData for CollectionView that is why you are not able to see anything in the CollectionView after data is being loaded into your array. I am updating your scanner method , try this and it will work.
func scanner(){
scanExpression.limit = 2000
db.scan(PostDetails.self, expression: scanExpression).continueWith(block: { (task:AWSTask!) -> AnyObject! in
if task.result != nil {
let paginatedOutput = task.result!
//use the results
for item in paginatedOutput.items as! [PostDetails] {
self.counter = paginatedOutput.items.count
self.images.append(item.userId!)
}
//This line is important because it tells collectionview that i have new data so please refresh.
PCV.reloadData()
if ((task.error) != nil) {
print("Error: Could not fetch PostDetails table data")
}
return nil
}
return nil
})
}