MBProgressHUD is not changing to customView - ios

Question

I am running around the issue, that MBProgressHUD should be updating its View with a Checkmark/X for succeeded/failed requests. Somehow this doesnt really work as intended and the update only works after all the code has executed.
initializing the HUD
...
MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
hud.labelText = #"Verifying Credit Card";
_HUD = hud;
CWAPIClient *client = [CWAPIClient sharedClient];
client.delegate = self;
dispatch_queue_t backgroundQueue = dispatch_queue_create("com.clubw.billing", 0);
dispatch_async(backgroundQueue, ^{
[client save:billingProfile with:[Address defaultBillingAddress]];
});
....
Callback to process information:
self POST:[NSString stringWithFormat:#"user/%#/billingprofile", [[Profile defaultProfile] userId]] parameters:params success:^(AFHTTPRequestOperation *operation, id responseObject) {
dispatch_async(dispatch_get_main_queue(), ^{
[self.delegate CWAPIClient:self doneVerifyingCreditCard:responseObject];
});
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"%#", error);
}];
callback when action is complete
BOOL success = [[jsonResponse objectForKey:#"success"] boolValue];
if (success)
{
NSLog(#"Thread: %#", [NSThread currentThread]);
dispatch_async(dispatch_get_main_queue(), ^{
UIImage *checkmarkImage = [UIImage imageNamed:#"checkmark.png"];
UIImageView *checkmarkView = [[UIImageView alloc] initWithImage:checkmarkImage];
_HUD.customView = checkmarkView;
_HUD.labelText = #"Credit Card Verified!";
_HUD.mode = MBProgressHUDModeCustomView;
NSLog(#"Thread: %#", [NSThread currentThread]);
sleep(5);
[_HUD hide:YES];
});
After the 5 seconds, it simply closed the HUD - and the updated one flashes for a second.
It seems, like this is a threading issue - but I cant seem to figure out where it is throwing up.

Answer 1

In the portion of the code where you make your callback, be sure to perform the callback on the main queue as well.