How to asynchronous load image from a web-server in UICollectionView using NSCache

by

Try this one it’s Working code (Swift 4).

func NKPlaceholderImage(image:UIImage?, imageView:UIImageView?,imgUrl:String,compate:@escaping (UIImage?) -> Void){

    if image != nil && imageView != nil {
        imageView!.image = image!
    }

    var urlcatch = imgUrl.replacingOccurrences(of: "https://stackoverflow.com/", with: "#")
    let documentpath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
    urlcatch = documentpath + "https://stackoverflow.com/" + "\(urlcatch)"

    let image = UIImage(contentsOfFile:urlcatch)
    if image != nil && imageView != nil
    {
        imageView!.image = image!
        compate(image)

    }else{

        if let url = URL(string: imgUrl){

            DispatchQueue.global(qos: .background).async {
                () -> Void in
                let imgdata = NSData(contentsOf: url)
                DispatchQueue.main.async {
                    () -> Void in
                    imgdata?.write(toFile: urlcatch, atomically: true)
                    let image = UIImage(contentsOfFile:urlcatch)
                    compate(image)
                    if image != nil  {
                        if imageView != nil  {
                            imageView!.image = image!
                        }
                    }
                }
            }
        }
    }
}

Use Like this :

// Here imgPicture = your imageView and UIImage(named: "placeholder") is Display image brfore download actual image.  
imgPicture.image = nil 
NKPlaceholderImage(image: UIImage(named: "placeholder"), imageView: imgPicture, imgUrl: "Put Here your server image Url Sting") { (image) in }

More Related Contents:

  1. How do I write dispatch_after GCD in Swift 3, 4, and 5?
  2. the behavior of the UICollectionViewFlowLayout is not defined, because the cell width is greater than collectionView width
  3. UICollectionView assertion error on stale data
  4. How to use swift 4 Codable in Core Data?
  5. Waiting until the task finishes
  6. How can I use String substring in Swift 4? ‘substring(to:)’ is deprecated: Please use String slicing subscript with a ‘partial range from’ operator
  7. Does ARC support dispatch queues?
  8. Swift 4 “This class is not key value coding compliant”
  9. Barcode on swift 4
  10. Forced to cast, even if protocol requires given type
  11. UICollectionView reloadData not functioning properly in iOS 7
  12. Workaround on the threads limit in Grand Central Dispatch?
  13. In Swift how to call method with parameters on GCD main thread?
  14. In iOS 12, when does the UICollectionView layout cells, use autolayout in nib
  15. View with continuous scroll; both horizontal and vertical
  16. UICollectionView adding image to a cell
  17. What is export * in module.modulemap file inside each framework?
  18. Swift 4 JSON Decodable with multidimensional and multitype array
  19. Core Data and threads / Grand Central Dispatch
  20. UICollectionView Assertion failure
  21. What is difference between optional and decodeIfPresent when using Decodable for JSON Parsing?
  22. navigation bar rightbaritem image-button bug iOS 11
  23. Access Firebase variable outside Closure
  24. UICollectionView cell subviews do not resize
  25. UIApplication.registerForRemoteNotifications() must be called from main thread only
  26. How to set UICollectionViewCell Width and Height programmatically
  27. UICollectionView – Horizontal scroll, horizontal layout?
  28. UIButton in cell in collection view not receiving touch up inside event
  29. Any when decoding JSON with Codable?
  30. In Swift 4, how do I remove a block-based KVO observer?

Leave a Comment