iOS UIAlertView-show

[yzhaocn]

-(IBAction)click: (id)sender
{
...
UIAlertView *alert = [[UIAlertView alloc] initWithTitle"Alert" message"This is a Alert!" delegate:nil cancelButtonTitle"Cancel" otherButtonTitles"OK", nil];
[alert show];
[alert release]; //<==breakpoint is added here;
...
}

When the Button is clicked, program excutes to the breakpoint but the UIAlertView is not appeared.

thanks.