How to use NSDefault

Primitive Object
// Get
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString* userId = [defaults objectForKey:@"UserId"];
[defaults synchronize];

// Set
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:userId forKey:@"UserId"];
[defaults synchronize];

// Clear

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

[defaults removeObjectForKey:@"UserId"];

[defaults synchronize];

Custom Object

// Get

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

NSData *formData = [defaults objectForKey:@"CustomObject"];

MyCustomData *data=[NSKeyedUnarchiver unarchiveObjectWithData:data];

[defaults synchronize];

// Set

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

NSData *data = [NSKeyedArchiver archivedDataWithRootObject:myCustomObject];

[defaults setObject:data forKey:@"CustomObject"];

[defaults synchronize];

// Clear

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

[defaults removeObjectForKey:@"CustomObject"];

[defaults synchronize];