UIAlertView seems to freeze application when uploading data to Parse.com - ios

Question

Hello I am using parse to help with the backend of my iOS app and I created a button that will save my text in my textfields and upload it to the cloud when I click a button.
The code for the button and the alert that pops up is as follows
- (IBAction)savebutton:(id)sender {
// Create PFObject with recipe information
PFObject *recipe = [PFObject objectWithClassName:#"GolfTimes"];
[recipe setObject:_nameTextField.text forKey:#"Name"];
[recipe setObject:_prepTimeTextField.text forKey:#"MemberNumber"];
[recipe setObject:_NumberOfGolfers.text forKey:#"NumberOfGolfers"];
[recipe setObject:_RequestedTime.text forKey:#"RequestedTime"];
NSArray *ingredients = [_ingredientsTextField.text componentsSeparatedByString: #","];
[recipe setObject:ingredients forKey:#"Telephone"];
// Show progress
MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
hud.mode = MBProgressHUDModeIndeterminate;
hud.labelText = #"Sending...";
[hud show:YES];
// Upload recipe to Parse
[recipe saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
[hud hide:NO];
if (!error) {
// Show success message
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Request Sent" message:#"We will get back to you with confirmation." delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
// Notify table view to reload the recipes from Parse cloud
[[NSNotificationCenter defaultCenter] postNotificationName:#"refreshTable" object:self];
// Dismiss the controller
[self dismissViewControllerAnimated:YES completion:nil];
} else {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Upload Failure" message:[error localizedDescription] delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
}
}];}
Although the data does send properly and the view controller does close as I made it do, the Alert seems to freeze the app and I cannot click the "Ok" most of the time. When I do click the "OK" button the app simulator shuts down.
Any suggestions or help?

Answer 1

I believe you need to dispatch the UIAlertView to the main thread like so when you want to show them: EDIT: You can't have the delegate of the UIAlertView be on the UIViewController you just dismissed! That's why it's crashing; setting the delegate to: nil should fix that.
dispatch_async(dispatch_get_main_queue(),^
{
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Request Sent" message:#"We will get back to you with confirmation." delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alert show];
[[NSNotificationCenter defaultCenter] postNotificationName:#"refreshTable" object:self];
[self dismissViewControllerAnimated:YES completion:nil];
});