Why does instantiating a UIAlertView take so long? - objective-c

Question

I have some code here for an iOS app I am developing, and for some reason what seems like a quick and simple task takes my iPhone 4S a full second or more to do, every time.
The context is this... I have a 2 button ActionSheet popup, and if the user taps either one of the buttons, the app seems to stall for about a second. Here's the code:
-(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex
{
if (buttonIndex == 0)
{
UIAlertView* newTimerAlertView = [[[UIAlertView alloc] initWithTitle:#"Create New Timer"
message:#"Enter a name for your new indicator"
delegate:self
cancelButtonTitle:#"Cancel"
otherButtonTitles:#"Create", nil] autorelease];
newTimerAlertView.tag = kNewTimer;
newTimerAlertView.alertViewStyle = UIAlertViewStylePlainTextInput;
[newTimerAlertView show];
}
else if (buttonIndex == 1)
{
NSLog(#"ActionSheet button 2 tapped");
UIAlertView* newTallyAlertView = [[[UIAlertView alloc] initWithTitle:#"Create New Tally"
message:#"Enter a name for your new indicator"
delegate:self
cancelButtonTitle:#"Cancel"
otherButtonTitles:#"Create", nil] autorelease];
newTallyAlertView.tag = kNewTally;
newTallyAlertView.alertViewStyle = UIAlertViewStylePlainTextInput;
[newTallyAlertView show];
NSLog(#"end");
}
}
Focusing on the second button for simplicity (although the first button behaves the same way), the log looks like this:
2012-01-25 20:35:46.330 ...[177:707] ActionSheet button 2 tapped
2012-01-25 20:35:47.194 ...[177:707] end
2012-01-25 20:35:56.154 ...[177:707] ActionSheet button 2 tapped
2012-01-25 20:35:56.180 ...[177:707] end
Notice that the first time I try it, over a second passes before the code snippet finishes executing, but the second time (and all subsequent times) the code only takes 30 or so milliseconds.
Is there something wrong with the code? or do I need to simply make up for the delay with a progress view?
Thanks!
EDIT: This only occurs on devices when running the app from Xcode... maybe it's got to do with the debugger?

Answer 1

I now that if the alert is not on the main thread they may be delayed

Answer 2

Xcode doesn't slow down alert views in any situation I have encountered.
Your code looks pretty plain vanilla, so I suspect there's something going on outside the snippet you posted.
I see that you reference timers... is is possible this is a manifestation of something else, like a timer callback, going wild on the main thread? Try using the Time Profiler or the System Trace instruments to figure out what's blocking (something certainly is).