NSUserDefaults Contains Value Or Not?

Question

How to know whether NSUserDefaults contains any value?How to check whether its empty?

Answer 1

There isn't a way to check whether an object within NSUserDefaults is empty or not. However, you can check whether a value for particular key is nil or not.

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

NSObject * object = [prefs objectForKey:@"your_particular_key"];
if(object != nil){
   //object is there
}

Answer 2

NSUserDefaults *data = [NSUserDefaults standardUserDefaults];  
NSString *string = [data objectForKey:@"yourKey"];
if(string==nil)
NSlog(@"nil")  

Take a look at NSUserDefault documentation

// For saving the values
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
// saving an NSString
[userDefaults setObject:@"Ttest" forKey:@"key"];
// --- For Retrieving

NSUserDefaults * userDefaults = [NSUserDefaults standardUserDefaults];
// getting an NSString
NSString *myString = [userDefaults stringForKey:@"key"];