Set NSUserDefaults for first time launch

Question

I have to following NSUserDefaults which I wish to be set to yes on the first time the user launches the app? How would I go about doing this? I'm aware it needs to be placed into AppDelegate however I can't work out how to do this.

NSUserDefaults *defaults =[NSUserDefaults standardUserDefaults];

[self.truthonoff setOn:[[defaults objectForKey:@"truthonoff"] boolValue] animated:YES];

[self.truthonoff addTarget:self action:@selector(stateSwitched:) forControlEvents:UIControlEventValueChanged];

[self.dareonoff setOn:[[defaults objectForKey:@"dareonoff"] boolValue] animated:YES];

[self.dareonoff addTarget:self action:@selector(stateSwitcheddare:) forControlEvents:UIControlEventValueChanged];
//other options

[self.shakesonoff setOn:[[defaults objectForKey:@"shakesonoff"] boolValue] animated:YES];

[self.shakesonoff addTarget:self action:@selector(stateSwitchedshakes:) forControlEvents:UIControlEventValueChanged];

[self.soundonoff setOn:[[defaults objectForKey:@"soundonoff"] boolValue] animated:YES];

[self.soundonoff addTarget:self action:@selector(stateSwitchedsound:) forControlEvents:UIControlEventValueChanged];

possible duplicate of [Detecting the initial launch of an app using NSUserDefaults](http://stackoverflow.com/questions/7023538/detecting-the-initial-launch-of-an-app-using-nsuserdefaults) — BytesGuy, Apr 13 '14 at 09:53

score 3 · Accepted Answer · answered Apr 12 '14 at 19:02

3

What you are looking for is -[NSUserDefaults registerDefaults:]

For example you could do something like:

+ (void)initialize
{
    if ([self class] == [AppDelegate class])
    {
        [[NSUserDefaults standardUserDefaults] registerDefaults:@{@"dareonoff":@NO}];
    }
}

The benefits of using registerDefaults is that deleting the a preference using -[NSUserDefault objectForKey:] reverts the key to it's default value declared in registeredDefaults.

answered Apr 12 '14 at 19:02

Alej

126
5

Would i place this in appdeligate? or in the view controller ? – user3502233 Apr 12 '14 at 19:07
You can place it in the AppDelegate in the `+(void)initialize` method. – Alej Apr 12 '14 at 19:08
Sadly this seems to crash the app on startup. Is the @NO ment to be as this @"NO" – user3502233 Apr 12 '14 at 19:12

score 0 · Answer 2 · answered Apr 12 '14 at 19:00

0

objectForKey: returns nil when the app is launced for the first time - or to be more accureate, when no value for the key was wever set before.

You should always check for nil when retreiving values from the user defaults. And when it is nil then you go forward with a resonalbe default value.

What happens here is that objectForKey retuns nil. Then you send boolValue to nil which returns a null value whihc is FALSE or NO in case of a bool.

answered Apr 12 '14 at 19:00

Hermann Klecker

14,039
5
48
71

WOW ok im confused now. How would i go about doing this? I think i follow the logic but not 100% – user3502233 Apr 12 '14 at 19:04
Are you asking how to use an if statement? – Hermann Klecker Apr 12 '14 at 19:07
No im just working out the logic here sorry – user3502233 Apr 12 '14 at 19:12
Go for Alejs suggesteion. It is the easiest in this case. – Hermann Klecker Apr 12 '14 at 20:04

score 0 · Answer 3 · edited May 23 '17 at 12:27

0

You can add initial values to Root.plist in Settings.bundle. And then you can register these defaults as described in this question:

iPhone - reading Setting.bundle returns wrong values

edited May 23 '17 at 12:27

Community

1
1

answered Apr 12 '14 at 19:41

Yuri Solodkin

530
8
26

Set NSUserDefaults for first time launch

3 Answers3