Loading images in background to optimize the loading in ios

Question

I am trying to optimize the load in my application, in fact, I have a lot of images that loaded in my application, and I spend a lot of time waiting for a view controller to ope

Answer 1

You can use async imageview.

- (void) loadImageFromURL:(NSURL*)url placeholderImage:(UIImage*)placeholder cachingKey:(NSString*)key {
    self.imageURL = url;
    self.image = placeholder;

    NSData *cachedData = [FTWCache objectForKey:key];
    if (cachedData) {   
       self.imageURL   = nil;
       self.image      = [UIImage imageWithData:cachedData];
       return;
    }

    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
    dispatch_async(queue, ^{
        NSData *data = [NSData dataWithContentsOfURL:url];

        UIImage *imageFromData = [UIImage imageWithData:data];

        [FTWCache setObject:data forKey:key];

        if (imageFromData) {
            if ([self.imageURL.absoluteString isEqualToString:url.absoluteString]) {
                dispatch_sync(dispatch_get_main_queue(), ^{
                    self.image = imageFromData;
                });
            } else {
//              NSLog(@"urls are not the same, bailing out!");
            }
        }
        self.imageURL = nil;
    });
}

Take a look at this link.You will have an idea on using async imageview.