Images pulled from url not appearing on UIImageView

Question

I wrote an app which goes and gets the url of an image from a RSS feed and displays it in a UIImageView and I know the image that I am pulling is valid because the url of the image goes straight to my label which shows the url and i typed it in and it goes to a image. It is a jpg image. What is annoying is that any image doesn't work even if I manually enter an url for an image.

This is my code , the image view code is down the bottom.

- (void)viewDidLoad {
    [super viewDidLoad];




    NSURL *URL = [NSURL URLWithString:@"http://rss.cnn.com/rss/edition_world.rss"];
    NSData *data = [NSData dataWithContentsOfURL:URL];

    // Assuming data is in UTF8.
    NSString *string = [NSString stringWithUTF8String:[data bytes]];
    titleLabelLatestNews.text = string;


    NSString *webString = titleLabelLatestNews.text;
    NSScanner *stringScanner = [NSScanner scannerWithString:webString];
    NSString *content = [[NSString alloc] init];
    while ([stringScanner isAtEnd] == NO) {
        [stringScanner scanUpToString:@"url=\"" intoString:Nil];
        [stringScanner scanUpToString:@"/>" intoString:&content];

        NSString *filteredImage = [content stringByReplacingOccurrencesOfString:@"url=\"" withString:@""];
        NSString *filteredImage2 = [filteredImage stringByReplacingOccurrencesOfString:@"\"" withString:@""];
        titleLabelLatestNews.text = filteredImage2;

        NSURL * imageURL = [NSURL URLWithString:filteredImage2];
        NSData * imageData = [NSData dataWithContentsOfURL:imageURL];
        UIImage * image = [UIImage imageWithData:imageData];
    [imageView setImage:image];



    }

The code I am using for the imageView -

NSURL * imageURL = [NSURL URLWithString:filteredImage2];
            NSData * imageData = [NSData dataWithContentsOfURL:imageURL];
            UIImage * image = [UIImage imageWithData:imageData];
        [imageView setImage:image];

Is it because of JPG? Is it because of my ImageView? Everything is linked up and everything is working fine except this I have seen all posts on how to get image from url and I tried everything but nothing seems to work the image view stays blank and white.

Summary : I am pulling a image link from a website and the link is valid because I tested it and any other image i try downloading and putting in the image view also doesn't work the image view is blank and shows nothing at all.

Thank you for your help!

Answer 1

Though this is a rudimentary code, I think I solved it

UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 100, 100, 100)];
[imgView setBackgroundColor:[UIColor redColor]];
[self.view addSubview:imgView];

NSURL *URL = [NSURL URLWithString:@"http://rss.cnn.com/rss/edition_world.rss"];
NSData *data = [NSData dataWithContentsOfURL:URL];

// Assuming data is in UTF8.
NSString *string = [NSString stringWithUTF8String:[data bytes]];


NSScanner *stringScanner = [NSScanner scannerWithString:string];
NSString *content = [[NSString alloc] init];
while ([stringScanner isAtEnd] == NO)
{
    [stringScanner scanUpToString:@"url=\"" intoString:Nil];
    [stringScanner scanUpToString:@"/>" intoString:&content];

    NSString *filteredImage = [content stringByReplacingOccurrencesOfString:@"url=\"" withString:@""];
    NSString *filteredImage2 = [filteredImage stringByReplacingOccurrencesOfString:@"\"" withString:@""];

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{ // 1
        NSData *imgData = [NSData dataWithContentsOfURL:[NSURL URLWithString:[filteredImage2 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]];
        dispatch_async(dispatch_get_main_queue(), ^{ // 2

            if(imgData)
            {
                UIImage *img = [UIImage imageWithData:imgData];
                if(img)
                {
                    [imgView setImage:img];
                }
                else
                {
                    NSLog(@" image url was %@ ",filteredImage2);
                }

            }
            else
            {
                 NSLog(@" image url was %@ ",filteredImage2);
            }

        });
    });
}

Answer 2

Ok, you don't see an image, because imageData is nil. imageData is nil, because imageURL is also nil.

You need to escape the url string before you create NSURL.

Instead of :

NSURL * imageURL = [NSURL URLWithString:filteredImage2];

Do:

NSURL * imageURL = [NSURL URLWithString:[filteredImage2 stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

Answer 3

To download a file using NSURLSession, do something like that:

 NSURLSession *downloadFileSession = [NSURLSession sessionWithConfiguration:[NSURLSessionConfiguration defaultSessionConfiguration]];
NSURLSessionDownloadTask *downloadTask =[downloadFileSession downloadTaskWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:path]] completionHandler:^(NSURL *location, NSURLResponse *response, NSError *error) {

// handle the response. 'location' is the file you downloaded

}];

[downloadTask resume];

But again, NSData should do the job. Re-check the url of the image, just before you start download it. You are modifying the url, so make sure it is valid.