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iOS Displaying API Data with Collection Views in Objective-C Show Me the Data - API’s, OAuth, and NSURLSession Queues and User Interface

Posted by Alexisca hall
Alexisca hall
23,683 Points

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 se

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];

        dispatch_async(dispatch_get_main_queue(), ^{
    self.imageView.image = image;

[task resume]; 

@end

1 Answer

Caleb Kleveter
MOD
Caleb Kleveter
Treehouse Moderator 37,862 Points
Caleb Kleveter
Caleb Kleveter
Treehouse Moderator 37,862 Points

Looks like you are missing your closing brace for the dispatch block:

#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];

        // This is how it should look
        dispatch_async(dispatch_get_main_queue(), ^{                                             
          self.imageView.image = image;
        }
    }];

    [task resume];
}

@end