IPhone SDK Default NSUserDefaults

Question

I have set up the user defaults to record a integer for a UISlider, the problem is that, if the user has only just installed the app then the integer is zero or NULL. Is the

Answer 1

If zero is not a valid value in a normal usage case (i.e. your saved preference would never set this integer to zero), then you can check

if( [prefs integerForKey:@"senset"] == 0){
    [prefs setInteger:25 forKey:@"senset"];
}

Edit: err, I suppose I have a question: when you try to overwrite it, are you setting an integer value(25) for your key (@"senset")? If not, then it will remain zero or nil, and everytime you check it will attempt to change your local senset variable to 25 again.

Answer 2

Just ask for objectForKey:. If it isn't set, it will return nil.

Your test doesn't work, because integerForKey: with an unset value will return 0, which is nil, which is NULL. The differences between them only exist to the compiler.

Answer 3

You should set a valid default value for each of your preferences. This value will be used when one has not been set by the user.

NSMutableDictionary *defaults = [NSMutableDictionary dictionary];
[defaults setObject:[NSNumber numberWithInt:25] forKey:@"senset"];
[[NSUserDefaults standardUserDefaults] registerDefaults:defaults];