Setting bundle default value won't set

问题

I have an iOS application with a settings.bundle that handles various settings for my application with Switch toggle. I set default values in my root.plist file (using the DefaultValue property) to YES but any time the application launches on a device or the iOS simulator all values go NO. It worked well only on the first launch.

I am retrieving the defaults with this code (am I doing something wrong here?):

NSUserDefaults *localeDefaults = [NSUserDefaults standardUserDefaults];
BOOL ENWORDS = [localeDefaults boolForKey:@"localetime"];

回答1:

The problem is the type of default Value must be boolean not string ;) delete this value and add a another default Value property again hope this helps

回答2:

The Default Value is used by Settings.app for display purposes only. If you don't change the value in the settings app nothing is saved to NSUserDefaults.

You have to register the default values yourself. Use something like this in application:didFinishLaunchingWithOptions::

NSDictionary *userDefaultsDefaults = [NSDictionary dictionaryWithObjectsAndKeys:
                                      [NSNumber numberWithBool:YES], @"localetime",
                                      nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:userDefaultsDefaults];

回答3:

This blog post might help : http://greghaygood.com/2009/03/09/updating-nsuserdefaults-from-settingsbundle

tl;dr - until the user opens the settings page then the defaults aren't copied into your app. This is the expected behavior by Apple.

Personally, I think this is terrible. It means that you will have to set your defaults in code just in case the user starts your app without going to the settings page first (which will be true for about 99% of use cases!)

回答4:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    //< Register Defaults
    NSString *settingsBundlePath = [[NSBundle mainBundle] pathForResource:@"Settings" ofType:@"bundle"];
    NSBundle *settingsBundle = [NSBundle bundleWithPath:settingsBundlePath];
    NSString *rootPlistPath = [settingsBundle pathForResource:@"Root" ofType:@"plist"];
    NSDictionary *settingsDict = [[NSDictionary alloc] initWithContentsOfFile:rootPlistPath];
    NSArray *settingsItems = [settingsDict objectForKey:@"PreferenceSpecifiers"];
    NSMutableDictionary *defaultDict = [NSMutableDictionary new];
    for (NSDictionary *itemDict in settingsItems) {
        if ([itemDict objectForKey:@"DefaultValue"]) {
            [defaultDict setObject:[itemDict objectForKey:@"DefaultValue"] forKey:[itemDict objectForKey:@"Key"]];
        }
    }
    [[NSUserDefaults standardUserDefaults] registerDefaults:defaultDict];
    //< Following Code
}

回答5:

You can check whether the value has been set by getting objectForKey and checking whether it is nil.

   NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
   id dataExists = [userDefaults objectForKey:@"light_switch"];
   BOOL lightSwitch;
   if (dataExists != nil) {
      lightSwitch = [userDefaults boolForKey:@"light_switch"];
       NSLog(@"light_switch is %d", validateCertificates);
   } else {
      lightSwitch = YES; // default value
      NSLog(@"light_switch not set, default value is %d", validateCertificates);
   }

来源：https://stackoverflow.com/questions/9181544/setting-bundle-default-value-wont-set

标签

ios

objective-c

nsuserdefaults

settings.bundle