Memory issue while downloading images Swift5 iOS13

Question

Overall memory growth

Whenever i get memory warning i'm clearing caches

func applicationDidReceiveMemoryWarning(_ application: UIApplication) {

        print("Memory warning...")
        imageCache.countLimit = 0
        imageCache.totalCostLimit = 0
        imageCache.removeAllObjects()
        SDImageCache.shared.clearMemory()
        URLCache.shared.removeAllCachedResponses()
    }

This is the code for downloading images and video thumbnails

     func collectionView(_ collectionView: UICollectionView, 
          cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

      image_url = [InputSource]()
     if item.media_url?.contains(".mp4") ?? false
     {

         DispatchQueue.global().async {

             UIImage.getThumbnailImage(forUrl: url) { (image) in
                             DispatchQueue.main.async {

                             self.imageView_Video.image = image
                        }
                    }
                }
            }
            else{

                image_url.append(AlamofireSource(url: url , placeholder: UIImage(named: AppConstants.image_placeholder)))
            }
            }

To download the image I'm using image slideshow 3rd party library

To download thumbnail I'm using the following code,

 static func getThumbnailImage(forUrl url: URL, completion: @escaping(_ 
  image: UIImage) -> Void) {

      DispatchQueue.global().async {

        do{
        let asset = AVURLAsset(url: url, options: nil)
        let imgGenerator = AVAssetImageGenerator(asset: asset)
        imgGenerator.appliesPreferredTrackTransform = true
        let cgImage = try imgGenerator.copyCGImage(at: CMTimeMake(value: 0, timescale: 1), actualTime: nil)

        DispatchQueue.main.async {
            let image = UIImage(cgImage: cgImage)
            completion(image)
        }

    } catch let error{
        print("*** Error generating thumbnail: \(error.localizedDescription)")

        DispatchQueue.main.async {
            completion(UIImage())
        }
    }
}
}

If i comment following code, the app will not crash

        image_url.append(AlamofireSource(url: url , placeholder: 
            UIImage(named: AppConstants.image_placeholder)))

Do you have a table view cell registered under `"connectionListItemCell"` programmatically or in your storyboard? — rolling_codes, Dec 12 '19 at 18:15
What is your overall memory growth over a reasonable period of time? There are leaks in UIKit. In a non-trivial app you will always see some memory leaks. The question is how much, and whether you're causing it. None of the code changes you're suggesting have anything to do with memory management, so I wouldn't expect them to change anything. — Rob Napier, Dec 12 '19 at 18:36
Please show actual code. Also please use Instruments or View Debugger to find out what is really leaking. — matt, Dec 12 '19 at 19:07
If i comment, image_url.append(AlamofireSource(url: url , placeholder: UIImage(named: AppConstants.image_placeholder))) this code. app will not crash. — Neelam Pursnani, Dec 13 '19 at 11:40

score 0 · Answer 1 · answered Dec 24 '19 at 12:30

I resolved this issue by changing the downloading image method as following,

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell 
{
   if let medias = history?.medias
    {
        if medias.count > 0
        {
            slides = [];

            for item in medias{

                if let url = URL(string: item.media_url ?? " "){

                    if item.media_url?.contains(".mp4") ?? false
                    {

                        self.imageView_Video.backgroundColor = UIColor.black.withAlphaComponent(0.8)
                        DispatchQueue.global().async {

                            if let cachedImage = AppDelegate.shared.imageCache.object(forKey: "\(url)" as NSString) {
                                DispatchQueue.main.async {
                                    self.imageView_Video.image = cachedImage
                                }
                            }else{
                                UIImage.getThumbnailFromUrl("\(url)") { [weak self] (image) in
                                    DispatchQueue.main.async {
                                        if let img = image{
                                            AppDelegate.shared.imageCache.setObject(img, forKey: "\(url)" as NSString? ?? NSString())
                                            self?.imageView_Video.image = img
                                        }
                                    }
                                }
                            }

                        }
                    }
                    else{


                        let slide1:Slide = Bundle.main.loadNibNamed("Slide", owner: self, options: nil)?.first as! Slide

                        let processor = DownsamplingImageProcessor(size: CGSize(width: 500, height: 500))
                            |> RoundCornerImageProcessor(cornerRadius: 0)
                        slide1.imageView?.kf.setImage(
                            with: url,
                            placeholder: UIImage(named: "i_placeholder"),
                            options: [
                                .processor(processor),
                            ])
                        { [weak self]
                            result in
                            switch result {
                            case .success(let value):

                                self?.slides.append(slide1)

                            case .failure(let error):

                                slide1.imageView?.image = UIImage(named: "i_placeholder")
                                self?.slides.append(slide1)

                            }

                            self?.setupSlideScrollView(slides: self?.slides ?? [])
                        }

                    }//end else
                }//end if let url

            }
        }
    }
 }

I removed the Slideshow library and added kingfisher to download high-resolution images.

Memory issue while downloading images Swift5 iOS13

1 Answers1