Downloading Images Fast in Swift

bhavuk chawla

14 December 2016

Downloading Images Fast in Swift

Suppose you want to display the number of images and you have to download that images from the Url. As downloading the images, view get stuck and can’t display all images, it will take too much time. To Resolve that problem, download images from URLSession and put a place holder until your images get displayed. Here is the Code :-

imageViewObject.image = UIImage(named: "placeholder")
self.downloadImage(url: NSURL(string: dict["image_path"]!) as! URL , tag: bannerTag)

1 2	imageViewObject.image = UIImage(named: "placeholder") self.downloadImage(url: NSURL(string: dict["image_path"]!) as! URL , tag: bannerTag)

image_path = image URL

bannerTag = tag of image

here is Downloading Image Function

func getDataFromUrl(url: URL, completion: @escaping (_ data: Data?, _  response: URLResponse?, _ error: Error?) -> Void) {
        URLSession.shared.dataTask(with: url) {
            (data, response, error) in
            completion(data, response, error)
            }.resume()
    }
    
    func downloadImage(url: URL , tag : Int) {
//        print("Download Started")
        getDataFromUrl(url: url) { (data, response, error)  in
            guard let data = data, error == nil else { return }
//            print(response?.suggestedFilename ?? url.lastPathComponent)
//            print("Download Finished")
            DispatchQueue.main.async() { () -> Void in

                if let temp : UIImageView = self.view.viewWithTag(tag) as? UIImageView{
                    temp.image = UIImage(data: data)
                }
                else{
//                    print("ff")
                }
            }
        }
    }

func getDataFromUrl(url: URL, completion: @escaping (_ data: Data?, _ response: URLResponse?, _ error: Error?) -> Void) {

URLSession.shared.dataTask(with: url) {

(data, response, error) in

completion(data, response, error)

}.resume()

}

func downloadImage(url: URL , tag : Int) {

// print("Download Started")

getDataFromUrl(url: url) { (data, response, error) in

guard let data = data, error == nil else { return }

// print(response?.suggestedFilename ?? url.lastPathComponent)

// print("Download Finished")

DispatchQueue.main.async() { () -> Void in

if let temp : UIImageView = self.view.viewWithTag(tag) as? UIImageView{

temp.image = UIImage(data: data)

}

else{

// print("ff")

}