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General Discussion

Posted by farisaljuma
farisaljuma
5,841 Points

iOS Development

It looks like we've written a bug. When we set our image on the image view, it's not working quite right. Fix this by setting the image on the image view using the main queue.

import "AwesomeViewController.h"

@implementation AwesomeViewController

  • (void)viewDidLoad { [super viewDidLoad];

    NSURL *url = [NSURL URLWithString:@"http://blog.teamtreehouse.com/wp-content/themes/treehouse/images/logo-blog2x.png"];

    NSURLRequest *request = [[NSURLRequest alloc] initWithURL:url]; NSURLSession *session = [NSURLSession sharedSession];

    NSURLSessionDownloadTask *task = [session downloadTaskWithRequest:request completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) { NSData *data = [[NSData alloc] initWithContentsOfURL:location]; UIImage *image = [[UIImage alloc] initWithData:data];

    self.imageView.image = image;

    }];

    [task resume]; }

@end

Whats wrong with this code?

1 Answer

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

The problem is that any updates to the UI will need to be called on the main thread (as opposed to a background thread which is what is currently happening). you can do that like so

dispatch_async(dispatch_get_main_queue(), ^{
   // do any updates to UI here such as setting an image views image
});