Async load multiple images to single cell - ios

Question

I have a problem with loading of 5 images to each cell of TableView. I use AFNetworking for download and setImageWithUrl method for imageView:
for (int i = 0; i < urls.count; i++) {
[self.photoImageView[i] setImageWithURL:urls[i]];
}
TableView very brakes when I scroll it. But when i try to load 1 or 2 no brakes when scrolling.
How to correct download images without brakes?

Answer 1

I think's it's helpful for you below the code work for me.
First fall you use this library SDWebImage
then implement below code.
#import <SDWebImage/UIImageView+WebCache.h>
...
[cell.imageView sd_setImageWithURL:[NSURL URLWithString:#"URL"]
placeholderImage:[UIImage imageNamed:#"placeholder.png"]];

Answer 2

You can use SDWebImage as discussed by #Ravi. You can use use the above code in your for loop to display all 5 images asynchronously , without blocking main thread.
for (int i = 0; i < urls.count; i++) {
[self.photoImageView[i] sd_setImageWithURL:[NSURL URLWithString:urls[i]]
placeholderImage:[UIImage imageNamed:#"placeholder.png"]];
}
If you dont want to use any third party libraries, you can also use GCD for the same. Check this ans.
Hope it helps. Happy Coding!!

Answer 3

If you see UIImage + AFNetworking class,It internally loads image using Async NSOperations.Try loading image with specific dimensions.It will download image of that size & could improve scrolling performance.
NSMutableString *newURLPath = [NSMutableString stringWithString[exercise.imageURL absoluteString]];
[newURLPath appendFormat:#"?width=200&"];
[newURLPath appendFormat:#"height=200"];

Answer 4

For downloading the Asynchronous image from url, use any of these library for improving the scroll performance
SDWebImage - Asynchronous image downloader with cache support as a UIImageView category.
#import <SDWebImage/UIImageView+WebCache.h>
...
[imageView sd_setImageWithURL:URL
placeholderImage:[UIImage imageNamed:#"placeholder.png"]
];
PINRemoteImage - It download a progressive jpeg and get attractive blurred updates.
For in your case, you can go for SDWebImage.
For Advance Concept, you could look into this one.
AsyncDisplayKit - Smooth asynchronous user interfaces for iOS apps
Even recently, Pinterest was built on top of AsyncDisplayKit to Keeps UIs smooth and responsive.
Read this article for more info: https://medium.com/#Pinterest_Engineering/re-architecting-pinterest-039-s-ios-app-e0a2d34a6ac2