Irregular cell images -Downloading images using gcd and adding to NSMutable array, then displaying in tableview cells

Question

I download images from links and add it to an NSMutableArray. This is then to be used as the cell image. I get a list of books from one link and filter the content of the table, then I have a separate link that has their corresponding images. The first link with the offers has an image path that is appended to a link to find the corresponding images. I am using grand central dispatch to load the images in the tableview. However the images do not always correspond to the correct book.

This is the code in question for cellForRowAtIndexPath:

dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(queue, ^{


 NSString * url = [NSString stringWithFormat:@"http://website/getBookImage.app?path=%@",[b.imgPath stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
 NSURL * imageURL = [NSURL URLWithString:url];

 NSData * imageData = [NSData dataWithContentsOfURL:imageURL];
 UIImage * newImage = [UIImage imageWithData:imageData];
 UIImage * noPic = [UIImage imageNamed:@"noPic.jpg"];

 //resize the images
 CGRect rect = CGRectMake(0,0,111,115);
 UIGraphicsBeginImageContext( rect.size );
 [newImage drawInRect:rect];
 UIImage *picture1 = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();

 UIGraphicsBeginImageContext( rect.size );
 [noPic drawInRect:rect];
 UIImage * pic2 = UIGraphicsGetImageFromCurrentImageContext();
 UIGraphicsEndImageContext();

 NSData *imageData2 = UIImagePNGRepresentation(picture1);
 NSData * noPicData = UIImagePNGRepresentation(pic2);

 //if image is
    if (imageData.length == 0 ) {

        [self.merchantImage addObject:noPicData];

    }else{

        [self.merchantImage addObject:imageData2];
    }

 NSLog(@"image data %@",imageData);

    //call to main thread to tell it that its done
    //set cells
    dispatch_async(dispatch_get_main_queue(), ^{

        //set cells here
        //3.set the image cell
        imageSection.image = [UIImage imageWithData:[self.bookImage objectAtIndex:i];
        //tell cell to redraw
        i++;
        [cell setNeedsLayout];
    });
    // }
});


return cell;

I am fairly new so I am sorry for any bad coding.

use SDWebImageView https://github.com/rs/SDWebImage – Bhumeshwer katre Nov 20 '13 at 12:48 — Bhumeshwer katre, Nov 20 '13 at 12:48

Suhit Patil · Accepted Answer · 2013-11-20T13:05:31.407

0

you can use AFNetworking which downloads the data and images asynchronously and very easy to use.

Edit: example on how to downloadImages

NSURL *URL = [NSString stringWithFormat:@"http://website/getBookImage.app?path=%@",[b.imgPath stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

NSURLRequest *request = [NSURLRequest requestWithURL:URL];
AFHTTPRequestOperation *op = [[AFHTTPRequestOperation alloc] initWithRequest:request];
op.responseSerializer = [AFJSONResponseSerializer serializer];
[op setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
    imageSection.image = responseObject;
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];
[[NSOperationQueue mainQueue] addOperation:op];

edited Nov 20 '13 at 13:05

answered Nov 20 '13 at 12:50

Suhit Patil

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You should consider adding an example of how OP could use this to solve the problem. – Mick MacCallum Nov 20 '13 at 12:55
I tried this but it didnt work, I used `SDWebImage` and it worked correctly – DevC Nov 20 '13 at 15:18
please refer this link http://stackoverflow.com/questions/19501652/how-to-download-image-with-afnetworking-2-0 – Suhit Patil Nov 21 '13 at 06:48

Irregular cell images -Downloading images using gcd and adding to NSMutable array, then displaying in tableview cells

1 Answers1