iOS SDWebImage fade in new image

Question

I\'ve been using SDWebImage on my iPhone app to handle all of the image loading. I am using a placeholder image, and I want to crossfade or fade in the new image once it loads.

Answer 1

Try out this:

[self.myImage sd_setImageWithURL:storyThumbnailURL placeholderImage:[UIImage imageNamed:@"xyz"] completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
    if (cacheType == SDImageCacheTypeNone) {
        self.myImage.alpha = 0;
        [UIView animateWithDuration:0.3 animations:^{
            self.myImage.alpha = 1;
        }];
    } else {
        self.myImage.alpha = 1;
    }
}];

Answer 2

This extension code worked better for me.

extension UIImageView {
  public func setImageWithFadeFromURL(url: NSURL, placeholderImage placeholder: UIImage? = nil, animationDuration: Double = 0.3) {
     self.sd_setImageWithURL(url, placeholderImage: placeholder) { (fetchedImage, error, cacheType, url) in
        if error != nil {
            print("Error loading Image from URL: \(url)\n(error?.localizedDescription)")
        }

        self.alpha = 0
        self.image = fetchedImage
        UIView.transitionWithView(self, duration: (cacheType == .None ? animationDuration : 0), options: .TransitionCrossDissolve, animations: { () -> Void in
            self.alpha = 1
        }, completion: nil)
    }
  }

  public func cancelImageLoad() {
    self.sd_cancelCurrentImageLoad()
  }
}

Answer 3

SWIFT:

func setSDWebImageWithAnimation(imageViewToSet mImageView:UIImageView, URLToSet imageURL:NSURL!)
    {
        mImageView.image = UIImage(named: "favouritePlaceholder")
        SDWebImageManager.sharedManager().downloadImageWithURL(imageURL, options: nil, progress: nil) { (downloadedImage:UIImage!, error:NSError!, cacheType:SDImageCacheType, isDownloaded:Bool, withURL:NSURL!) -> Void in
            mImageView.alpha = 0
            UIView.transitionWithView(mImageView, duration: 1.0, options: UIViewAnimationOptions.TransitionCrossDissolve, animations: { () -> Void in
                mImageView.image = downloadedImage
                mImageView.alpha = 1
                }, completion: nil)

        }
    }

Answer 4

You could set the imageView.alpha to 0 right before the animation block, then in the animation block have it animate back to imageView.alpha = 1.0;

// load placeholder image
NSURL *url = ...
_imageView = [[UIImageView alloc] init];
[_imageView setImage:[UIImage imageNamed:@"loading.jpg"]];

// request image
SDWebImageManager *manager = [SDWebImageManager sharedManager];
[manager downloadWithURL:url
            delegate:self
             options:0
             success:^(UIImage *image, BOOL cached) {

                  imageView.alpha = 0.0;
                 [UIView transitionWithView:_imageView
                                   duration:3.0
                                    options:UIViewAnimationOptionTransitionCrossDissolve
                                 animations:^{
                                     [_imageView setImage:image];
                                      imageView.alpha = 1.0;
                                 } completion:NULL];

}
failure:nil];

Answer 5

For SWIFT, i created this extension. It only fades in, when the image actually had to be downloaded from the web. If it was served from the cache, then it won't fade.

import UIKit
import SDWebImage

extension UIImageView {

    public func sd_setImageWithURLWithFade(url: NSURL!, placeholderImage placeholder: UIImage!)
    {        self.sd_setImageWithURL(url, placeholderImage: placeholder) { (image, error, cacheType, url) -> Void in

        if let downLoadedImage = image
        {
            if cacheType == .None
            {
                self.alpha = 0
                UIView.transitionWithView(self, duration: 0.2, options: UIViewAnimationOptions.TransitionCrossDissolve, animations: { () -> Void in
                    self.image = downLoadedImage
                    self.alpha = 1
                    }, completion: nil)

            }
        }
        else
        {
            self.image = placeholder
        }
        }
    }
}

Answer 6

SDWebImage now offers a built-in fade transition as of 4.3.0.

imageView.sd_imageTransition = SDWebImageTransition.fadeTransition;
imageView.sd_setImage(with: ...)

See the documentation here, you can perform more complex transitions using their API.

https://github.com/rs/SDWebImage/wiki/Advanced-Usage#image-transition-430