UI hang before Call back of SignalR - ios

Question

Im using signalR for sending data here is my code to send data.
manager = [AFHTTPRequestOperationManager manager];
manager.responseSerializer = [AFJSONResponseSerializer serializer];
manager.responseSerializer.acceptableContentTypes = [NSSet setWithObject:#"application/json"];
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setValue:#"application/json" forHTTPHeaderField:#"Content-Type"];
setUrl = [NSString stringWithFormat:#"%#%#",[UtilHelper sharedManager].WebServiceURL,#"Save"];
NSDictionary *parameters = [[NSDictionary alloc]initWithObjectsAndKeys:dicArray,#"products", nil];
__block NSMutableArray* json;
json = [[NSMutableArray alloc]init];
[manager POST:setUrl parameters:parameters success:^(AFHTTPRequestOperation *operation, id responseObject) {
NSError *writeError = nil;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:responseObject options:NSJSONWritingPrettyPrinted error:&writeError];
NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsonData
options:NSJSONReadingMutableContainers
error:&writeError];
if ([[dic valueForKey:#"StatusMsg"] isEqualToString:#"Success"]) {
// save To S3 Bucket
[self sendPicture:[NSString stringWithFormat:#"%#",strProductId] : strPackageId];
[[results objectAtIndex:i] setValue:[NSNumber numberWithBool:YES] forKey:#"productsync"];
[[results objectAtIndex:i] setValue:[NSNumber numberWithBool:YES] forKey:#"editflag"];
[context save:nil];
}
}
failure:^(AFHTTPRequestOperation *operation, NSError *error) {
}];
Now im getting SignalR response in AppDelegate
[hubConnection setReceived:^(NSString *message) {
NSLog(#"%#",message);
});
When setReceived called my UI hand here is my code that i present my UIViewController that i present and hang UI init
-(void)handlePlusOption{
__weak __typeof(&*self)weakSelf = self;
dispatch_async( dispatch_get_main_queue(), ^{
__strong __typeof(&*weakSelf)strongSelf = weakSelf;
strongSelf.addProductVc = [[AddProductVC alloc] initWithNibName:addProductVcIdentifier bundle:nil];
strongSelf.nav = [[UINavigationController alloc] initWithRootViewController:strongSelf.addProductVc];
strongSelf.nav.modalPresentationStyle = UIModalPresentationFormSheet;
strongSelf.nav.modalTransitionStyle=UIModalTransitionStyleCoverVertical;
strongSelf.nav.modalPresentationCapturesStatusBarAppearance = NO; // To hide status bar, doest work with UIModalPresentationPageSheet style
[self.navigationController presentViewController:strongSelf.nav animated:YES completion:NULL];
});
}
Why UI hang before setReceived ?

Answer 1

try to put your setReceived block of code inside this block ..
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// time-consuming task
[hubConnection setReceived:^(NSString *message) {
NSLog(#"%#",message);
}];
dispatch_async(dispatch_get_main_queue(), ^{
// run in main thread
});
});