setImageWith Url completion block swift ios - ios

Question

I am new to swift. I am loading image with url
mainImageView.setImageWith(URL(string: ("https:" + (content?.imagePath)!)), placeholderImage: nil)
print("dimensions after loading \(String(describing: mainImageView.image?.size))")
In case, I print the dimensions of the image as shown above then dimensions come out to be 21*6.5. However, if I wait for sometime and then print the dimensions are 188*109. How do I add a completion block to setImageWith so that I can come to know when image has finished loading?

Answer 1

You can use Sdwebimage for loading the image with completion block https://github.com/rs/SDWebImage
imageView.sd_setImageWithURL(NSURL(string: urlString), completed: {
(image, error, cacheType, url) in
// you can get the image width here...
})

Answer 2

It is happening because URL will always take a time to load image thats why first you got 21*6.5 dimensions and then got real dimensions 188*109.
As best way to prefer 3rd party library SDWebImage that will manage all the thing, You just need to set image URL.
There is method name is
open func sd_setImage(with url: URL!, placeholderImage placeholder: UIImage!, options: SDWebImageOptions = [], completed completedBlock: SDWebImage.SDWebImageCompletionBlock!)
that has completion block so you can manage whatever you want.

Answer 3

Convert image URL into data then Data into UIIamge, Here is a function:
func getImageFromUrl(_ strUrl: String, completionHandler handler: #escaping (_ img: UIImage) -> Void) {
DispatchQueue.global(qos: .background).async {
let url = URL(string: strUrl)
let dataFromUrl = Data(contentsOf: url!)
if dataFromUrl == nil {
return
}
DispatchQueue.main.async(execute: {() -> Void in
handler(UIImage(data: dataFromUrl!))
})
})
}

Answer 4

Use This: -
let imageCache = NSCache<AnyObject, AnyObject>()
typealias CompletionHandler = (_ success:Bool, _ image:UIImage?) -> Void
func loadImageUsingCacheWithUrlString(_ urlString:
String,completionHandler: #escaping CompletionHandler) {
let image = UIImage()
//check cache for image first
if let cachedImage = imageCache.object(forKey: urlString as AnyObject) as? UIImage {
image = cachedImage
completionHandler(true, image!)
return
}
if urlString.characters.count == 0 {
completionHandler(false, image)
return
}
//otherwise fire off a new download
let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!, completionHandler: { (data, response, error) in
//download hit an error so lets return out
if error != nil {
print(error ?? "")
completionHandler(false,nil)
return
}
DispatchQueue.main.async(execute: {
if let downloadedImage = UIImage(data: data!) {
image = downloadedImage
imageCache.setObject(downloadedImage, forKey: urlString as AnyObject)
completionHandler(true,image)
}
})
}).resume()
}