stringWithContentsOfUrl in background - ios

Question

UPDATE: Here's all the file's I'm using in my github repo. Perhaps it will help more than my code snippets:
appDelegate
mainViewController
calendarHandler
NSString* result = [NSString stringWithContentsOfURL:urlRequest encoding:NSUTF8StringEncoding error:&err];
That's the line I'm using in my project to get data from a website. I run this in an NSOperationQueue and when I run with my app in the foreground, it works without issue. However I also have my app set to run in the background using performFetchWithCompletionHandler. All of my setup code works fine using the performFetch, but when it hits the line I've outlined above, the app just hangs until I bring my app into the foreground again.
How can I let this work in the background?
In my AppDelegate I have performFetchWithCompletionHandler:
- (void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler
{
UINavigationController *navigationController = (UINavigationController*) self.window.rootViewController;
id topViewController = navigationController.topViewController;
if ([topViewController isKindOfClass:[ViewController class]])
{
[(ViewController*)topViewController autoLogin];
}
completionHandler(UIBackgroundFetchResultNewData);
}
My NSOperationQueue is built like this in my MainViewController:
- (void) autologin
{
NSOperationQueue* backgroundQueue = [NSOperationQueue new];
ch = [[myEventHandler alloc] init];
NSInvocationOperation* operation = [[NSInvocationOperation alloc] initWithTarget:ch selector:#selector(runEvents:) object:login];
[backgroundQueue addOperation:operation];
}
And in MyEventHandler I have runEvents
- (void) runEvents
{
NSURL* urlRequest = [NSURL URLWithString:#"http://www.google.com"];
NSError* err = nil;
NSString* result = [NSString stringWithContentsOfURL:urlRequest encoding:NSUTF8StringEncoding error:&err];
}

Answer 1

Try with This code:
NSString *urlString=[NSString stringWithFormat:#"%#listcontact.php?uid=%#&page=0",LocalPath,appdel.strid];
NSURL *url = [NSURL URLWithString:urlString];
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:urlRequest queue:[NSOperationQueue currentQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error)
{
NSError *error1;
NSDictionary *res=[NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingMutableLeaves error:&error1];
}];

Answer 2

have you tried using NSURLConnection (asynchronous) instead of stringWithContentsOfURL (synchronous)?
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:#"http://google.com"]];
[NSURLConnection sendAsynchronousRequest:request queue: [NSOperationQueue mainQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
NSString *theResult = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
// blah blah
}];