Iphone: Use of NSUserDefault

NSUserDefaults class gives us an opportunity to save values without requiring any database. This class uses Key-value coding structure model for saving and loading values. Key-value coding defines generic properties accessor methods—valueForKey: and setValue:forKey:—which identify properties through Key Value Same As Dictionary.

Object for NSUserDefault:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

Save Values In NSUserDefault:

// Saving an Object

[prefs setObject:obj forKey:@"keyObj"];

// saving an NSString
[prefs setObject:@"String" forKey:@"keyString"];

// saving an NSInteger
[prefs setInteger:10 forKey:@"KeyInt"];

// saving a Double
[prefs setDouble:4.112 forKey:@"KeyDouble"];

// saving a Float
[prefs setFloat:1.000045 forKey:@"KeyFloat"];

// This is suggested to synch the NS Object,

[prefs synchronize];

Retrieving Value From NSUserDefault:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an Object
NSObject *myObj = [prefs objectForKey:@"KeyObj"];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyString"];

// getting an NSInteger
NSInteger myInt = [prefs integerForKey:@"keyInt"];

// getting an Float
float myFloat = [prefs floatForKey:@"keyFloat"];

Basically NSUserDefault is used to store value for further use when database is not user or store value for any system crash.

thanks