How to show an activity indicator in SDWebImage

Question

Currently i am integrating SDWebImage in my project by following below things

1)#import \"UIButton+WebCache.h\"

2)[button setImageWithURL:url placeholderImag

Answer 1

The best way I have found to do this is to use the SDWebImageManager class. Your view controller or some other class will then need to conform to the SDWebImageManagerDelegate protocol.

SDWebImageManager *manager = [SDWebImageManager sharedManager];
UIImage *cachedImage = [manager imageWithURL:url];

if (cachedImage) {
    [button setImage:cachedImage];
    // stop or remove your UIActivityIndicatorView here
}
else {
    [manager downloadWithURL:url delegate:self];
}

Once the image has been downloaded the delegate method will be called:

- (void)webImageManager:(SDWebImageManager *)imageManager didFinishWithImage:(UIImage *)image {
    [button setImage:image];
    // stop or remove your UIActivityIndicatorView here
}

There is also a delegate method for when an error occurs downloading an image

- (void)webImageManager:(SDWebImageManager *)imageManager didFailWithError:(NSError *)error {
    // Handle error here
}

If you have more than one button you may have problems determining which image belongs to which button after the image has downloaded. In this case you may need to have a button subclass which handles the download as above and then updates its own image.

Hope that helps.