UIAlertController showing with delay

Question

I'm experiencing a problem with UIAlertController on my app now migrated to iOS8 with Date Picker inside.

Below is the code.

UIAlertController *AlertView = [UIAlertController alertControllerWithTitle:title message:nil preferredStyle:UIAlertControllerStyleActionSheet];   UIAlertAction *ok = [UIAlertAction actionWithTitle:@"Ok" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) { [AlertView dismissViewControllerAnimated:YES completion:nil]; }];   UIAlertAction *set = [UIAlertAction actionWithTitle:NSLocalizedString(@"Set to today", nil) style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) { [self set_to_today:nil]; [AlertView dismissViewControllerAnimated:YES completion:nil]; [self.tableView reloadData]; }];   UIAlertAction *cancel = [UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) { [AlertView dismissViewControllerAnimated:YES completion:nil]; }];    UIDatePicker *datePicker = [[[UIDatePicker alloc] init] autorelease];  datePicker.datePickerMode = UIDatePickerModeDate; [datePicker setDate:data_appo]; [datePicker addTarget:self action:@selector(datePickerValueChanged:) forControlEvents:UIControlEventValueChanged];  [AlertView.view addSubview:datePicker]; [AlertView addAction:ok]; [AlertView addAction:set]; [AlertView addAction:cancel]; [self.view bringSubviewToFront:datePicker]; [self presentViewController:AlertView animated:YES completion:nil]; 

UIAlertController and Date Picker is shown when the user select a row from UITableViewController.

The problem is the following: first time the users select the row everything works fine...but if the user select "Cancel" and then select de tate again the UIAlertController takes 2-3 seconds to show up...this happens also in the simulator...

I'm getting crazy....this makes my app have a bad user experience.

Any help will be strongly appreciated Thanks

Alex

Answer 1

I was having the same issue with a UIAlertController presented by selecting a row from a UITableView. The first time everything worked fine, and then when the user triggered the alert again there was a few seconds delay before the alert was actually presented.

As a workaround I used GCD:

    dispatch_async(dispatch_get_main_queue(), ^{         [self presentViewController:AlertView animated:YES completion:nil];     }); 

It is probably a bug since -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath is already executed on the main thread.

I submitted a bug report to Apple: rdar://19285091

Answer 2

    DispatchQueue.main.async {         self.present(alertView, animated: true, completion:nil)     } 

Swift 3.0 version. Alternatively, setting animated: false also solved my problem.