iOS 利用SDWebImage做简单的淡入淡出动画

利用SDWebImage做简单的淡入淡出动画：

[self.adImageView sd_setImageWithURL:url completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType, NSURL *imageURL) {
    self.adImageView.alpha = 0.0;
    [UIView transitionWithView:self.adImageView
                      duration:1.0
                       options:UIViewAnimationOptionTransitionCrossDissolve
                    animations:^{
                        [self.adImageView setImage:image];
                        self.adImageView.alpha = 1.0;
                    } completion:NULL];
}];