How to show an activity indicator in SDWebImage

问题:

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

1)#import "UIButton+WebCache.h"

2)[button setImageWithURL:url placeholderImage:[UIImage imageNamed:@"no_photo.png"]];

So it will show the list of image present in URL above the respective buttons.

But Now i want to show an activity indicator above button when the image is getting downloaded ,So how can i do this?

回答1:

Works like a charm for me :

Swift 3:

imgView.setShowActivityIndicator(true)
imgView.setIndicatorStyle(.gray)
imgView.sd_setImage(with: URL(string: urlString), placeholderImage: UIImage(named: "placeholder"))

Swift 4: (Edit : Updates)

imgView.sd_setShowActivityIndicatorView(true)
imgView.sd_setIndicatorStyle(.gray)
imgView.sd_setImage(with: URL(string: urlString), placeholderImage: UIImage(named: "placeholder"))

回答2:

Last solution

You can download UIActivityIndicator-for-SDWebImage, which is easiest way to add a UIActivityView to your SDWebImage view. Using CocoaPods, just add this line to your podfile:

pod 'UIActivityIndicator-for-SDWebImage'

You can use one of these lines depending on your preferences:

- (void)setImageWithURL:(NSURL *)url usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;
- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;
- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;
- (void)setImageWithURL:(NSURL *)url completed:(SDWebImageCompletionBlock)completedBlock usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;
- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder completed:(SDWebImageCompletionBlock)completedBlock usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;
- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options completed:(SDWebImageCompletionBlock)completedBlock usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;
- (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options progress:(SDWebImageDownloaderProgressBlock)progressBlock completed:(SDWebImageCompletionBlock)completedBlock usingActivityIndicatorStyle:(UIActivityIndicatorViewStyle)activityStyle;

Example of Use

Just import

#import <UIActivityIndicator-for-SDWebImage/UIImageView+UIActivityIndicatorForSDWebImage.h>

and use this code

[imageView setImageWithURL:[NSURL URLWithString:@"https://media.licdn.com/mpr/mpr/wc_200_200/p/1/005/07f/0a3/30cb8dd.jpg"] placeholderImage:[UIImage imageNamed:@"myImage.jpg"] usingActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

回答3:

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.

回答4:

the best way is to add the activityIndicator in all "setImage" functions in UIImageView+WebCache.m, after that you remove it in "webImageManager:r didFinishWithImage:" , i test it in device and it work smoothly, her's an example :

  - (void)setImageWithURL:(NSURL *)url placeholderImage:(UIImage *)placeholder
 {


UIActivityIndicatorView *activity = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:(UIActivityIndicatorViewStyleWhiteLarge)];
[activity startAnimating];
[activity setCenter:self.center];
[self addSubview:activity];
[activity release];



SDWebImageManager *manager = [SDWebImageManager sharedManager];

UIImage *cachedImage = [manager imageWithURL:url];

if (cachedImage)
{
    // the image is cached -> remove activityIndicator from view
    for (UIView *v in [self subviews])
    {
        if ([v isKindOfClass:[UIActivityIndicatorView class]])
        {
            [activity removeFromSuperview];
        }
    }
}

[self setImageWithURL:url placeholderImage:placeholder options:0];
}

and you remove it with a fade animation ;) :

 - (void)webImageManager:(SDWebImageManager *)imageManager didFinishWithImage:(UIImage *)image
{ 

for (UIView *v in [self subviews])
{
    if ([v isKindOfClass:[UIActivityIndicatorView class]])
    {
       // NSLog(@"-didFinishWithImage-");
        [((UIActivityIndicatorView*)v) stopAnimating];
        [v removeFromSuperview];
    }
}


[UIView beginAnimations:@"fadeAnimation" context:NULL]; 
[UIView setAnimationDuration:0.9];
self.alpha = 0;
self.image = image;
self.alpha=1;
//[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:self cache:YES]; 
[UIView commitAnimations];

 }