Showing an UIAlertView the first time the app is launched only - iphone

Question

Am I doing something wrong in getting an UIAlertView to play the first time only? In my didFinishLaunchingWithOptions, my MainViewController gets instantiated. So in MainViewController's viewDidLoad, I do this:
BOOL shouldAlert = [[NSUserDefaults standardUserDefaults] boolForKey:#"ShowAlert"];
if (!shouldAlert) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"MyAlert" message:#"Some text here" delegate:self cancelButtonTitle:#"Continue" otherButtonTitles: nil];
[alert show];
[alert release];
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"ShowAlert"];
[[NSUserDefaults standardUserDefaults] synchronize];
}
When I try it on the device, it doesn't work if I double tap home, and hit the minus sign next to the app to remove it from the background mode (I think that's what double tapping does right?). Cause after I do that, the pop up appears again. If I don't do that, than the alert only shows once. Is this expected behavior? Thanks a bunch.

Answer 1

you get your shouldAlert first time from userdefauls?
I think you should check if the userdefaults exists else your bool is NO or FALSE
check this example:
NSUserDefaults *userDef = [NSUserDefaults standardUserDefaults];
shouldAlert = YES; // define in the .h
if(userDef)
shouldAlert = [userDef boolForKey:#"ShowAlert"];

Answer 2

Try with an integer (0 / 1). I had some problems too with BOOL.
setInteger:forKey:
integerForKey:
EDIT
Try updating the defaults before initing/showing the alert.
And please, update your variable names. Your code is a nonsense with their current name.
Try this :
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
BOOL hasAlreadyBeenLaunched = [defaults boolForKey:#"HasAlreadyBeenLaunched"];
if (!hasAlreadyBeenLaunched) {
[defaults setBool:YES forKey:#"HasAlreadyBeenLaunched"];
[defaults synchronize];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"MyAlert" message:#"Some text here" delegate:self cancelButtonTitle:#"Continue" otherButtonTitles: nil];
[alert show];
[alert release];
}