`NSUserDefaults` not saving float properly - ios

Question

I am building an application in which I want to save some user data by using NSUserDefaults, and it is a property of one of my controllers as following:
#property (nonatomic, strong) NSUserDefaults *userPreference;
#synthesize userPreference = _userPreference;
And I am trying to save something called a scale that should be a float, so I do something like this in the getter to put in some default values of scale in case user did not enter one:
if (!_userPreference) {
_userPreference = [NSUserDefaults standardUserDefaults];
}
if (![_userPreference floatForKey:#"scale"]) {
// if user has not entered this info yet
// also 0 is not a valid value so I can do this
[_userPreference setFloat:100.0 forKey:#"scale"]; // let default scale be 100.0
[_userPreference synchronize];
}
However, when I later on query this, no matter what I set in the default value, the following command:
[self.userPreference floatForKey:#"scale"];
always return 1. I am not sure what is happening. Am I not creating the NSUserDefaults correctly?
Thank you in advance!

Answer 1

if you want to use NSUserDefaults, do not create any variables or #propertys. Just use
[[NSUserDefaults standardUserDefaults] setFloat:forKey:]
[[NSUserDefaults standardUserDefaults] synchronize];
to save your data and
[[NSUserDefaults standardUserDefaults] floatForKey:]
for fetching data.

Answer 2

Store using
[_userPreference setObject:[NSNumber numberWithFloat:100.0] forKey:#"Scale"];
[_userPreference synchronize];
and retrieve it using
float value = [[_userPreference objectForKey:#"Scale"] floatValue];

Answer 3

Have you tried this to set the float value:
[_userPreference setObject:[NSNumber numberWithFloat:100.0f] forKey#"scale"];
and the following to retrieve:
CGFloat scale = [[_userPreference objectForKey#"scale"] floatValue];

Answer 4

Change your if condition to this:
if ([_userPreference floatForKey:#"scale"] == 0.0f ) {
NSUserDefaults will always return 0.0f if no value is set for the key. Since you are saying that "also 0 is not a valid", you can safely use this approach

Answer 5

try this
-(void) saveFloatToUserDefaults:(float)x forKey:(NSString *)key {
NSUserDefaults * userDefaults = [NSUserDefaults standardUserDefaults];
[userDefaults setFloat:x forKey:key];
[userDefaults synchronize];
}
-(float) retriveFromUserDefaultsForKey:(NSString *)key {
NSUserDefaults * userDefaults = [NSUserDefaults standardUserDefaults];
return [userDefaults floatForKey:key];
}
[self saveFloatToUserDefaults:6.55 forKey:#"myFloat"];
float x = [self retriveFromUserDefaultsForKey:#"myFloat"];