NSUserDefaults, do something on first load only

Question

I\'m trying to do show an alert the first time the app is launched. I\'d also like to show this alert if they go into a settings page later on and want to see it again. I

Answer 1

Just think it backwards, instead of expecting a YES, set a variable when the app is actually launched, and remove it when the user says so in the settings.

At launch:

if (![[NSUserDefaults standardUserDefaults] boolForKey:@"hasBeenLaunched"]) {
    // show your only-one-time view
    [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"hasBeenLaunched"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

And when the user wants to see it again, just remove the key:

[[NSUserDefaults standardUserDefaults] removeObjectForKey:@"hasBeenLaunched"];

When accessing a key that does not exists, NSUserDefaults will return nil.