Question

Since iOS6 I have a very weird issue with UIImages that causes the application to crash.
The full method is like this:

NSURL *url = [NSURL URLWithString:@"http://api.twitter.com/1/users/show.json"];

NSDictionary *parametros = [NSDictionary dictionaryWithObjectsAndKeys:account.username, @"screen_name", nil];

SLRequest *request = [SLRequest requestForServiceType:SLServiceTypeTwitter
                            requestMethod:SLRequestMethodGET
                            URL:url
                            parameters:parametros];
[request setAccount:account];
[request performRequestWithHandler:^(NSData *responseData, NSHTTPURLResponse *urlResponse, NSError *error) {
        if ([urlResponse statusCode] == 200) {
            NSError *error_ = nil;
            NSDictionary *userInfo = [NSJSONSerialization JSONObjectWithData:responseData options:kNilOptions error:&error_];
            UIImage *image = [UIImage imageWithData:[userInfo objectForKey:@"profile_image_url"]];
            UIImage *image = [UIImage imageWithData:[userInfo objectForKey:@"profile_image_url"]];
            dispatch_sync(dispatch_get_main_queue(), ^{
                [_imageCache setObject:image forKey:account.username];
                [ListAccount reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:NO];
            });
        }
    }];

The problem occur in this line

UIImage *image = [UIImage imageWithData:[userInfo objectForKey:@"profile_image_url"]];

This was no problem in iOS5. I can’t seem to find why or someone that had the same problem. Any suggestion will be really appreciated

The crash is the following:

2012-09-28 17:30:53.600 Catalogo[7321:c07] -[__NSCFString bytes]: unrecognized selector     sent to instance 0x10eaf180
2012-09-28 17:30:53.601 Catalogo[7321:c07] *** Terminating app due to uncaught exception     'NSInvalidArgumentException', reason: '-[__NSCFString bytes]: unrecognized selector sent to     instance 0x10eaf180'
*** First throw call stack:
(0x2aed012 0x1a28e7e 0x2b784bd 0x2adcbbc 0x2adc94e 0x2a75390 0x203630c 0x2035e7e 0x2035d98     0x10dc23d 0xf991f3 0xf98ef4 0x6c54e 0x1b9e731 0x1bad014 0x1b9d7d5 0x2a93af5 0x2a92f44     0x2a92e1b 0x2dd87e3 0x2dd8668 0xf7765c 0x79cd 0x2d45)
libc++abi.dylib: terminate called throwing an exception

The following:

[userInfo objectForKey:@"profile_image_url"]

return the url of a twitter profile image

Answer 1

You need to convert [userInfo objectForKey:@"profile_image_url"] into NSData, then pass it to imageWithData:.

NSString * profileImageString = [userInfo objectForKey:@"profile_image_url"];
NSData * profileImageData = [profileImageString dataUsingEncoding:NSUTF8StringEncoding];

Than use:

UIImage *image = [UIImage imageWithData:profileImageData];