Why doesn't NSUserDefault work with my dictionary object? [duplicate] - objective-c

Question

This question already has answers here:
How to store custom objects in NSUserDefaults
(7 answers)
Closed 9 years ago.
I created an object for a make believe user that stores the username and password, I then put the object in a dictionary. Now I'm trying to store the dictionary using NSUserDefault but its not letting me. I understand its best not to use NSUserDefault to store user data but this is just beginner stuff I'm trying to learn.
/**interface file **/
#import "newUser.h"
#interface BWViewController : UIViewController
{
IBOutlet UITextField *userNameField;
IBOutlet UITextField *passwordField;
IBOutlet UILabel * loginStatus;
}
#property (nonatomic, copy) NSDictionary * aUser;
-(IBAction)signUpButton;
#end
/**implementation file**/
#interface BWViewController ()
#end
#implementation BWViewController
#synthesize aUser;
- (void)viewDidLoad
{
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
-(IBAction) signUpButton
{
newUser * firstUser = [[newUser alloc] init];
firstUser.userName = userNameField.text;
firstUser.password = passwordField.text;
NSLog(#"%#", firstUser.userName); /**for testing**/
NSLog(#"%#", firstUser.password); /**for testing**/
aUser = [[NSDictionary alloc] initWithObjects:[NSArray arrayWithObjects:firstUser, nil] forKeys:[NSArray arrayWithObjects:userNameField.text, nil]];
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:aUser forKey:userNameField.text];
[defaults synchronize];
loginStatus.text = #"Thanks for signing up!";
}

Answer 1

The better way to do that is store two user defaults one for username and one for password:
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:firstUser.userName forKey:#"USERNAME"];
[defaults setObject:firstUser.password forKey:#"PASSWORD"];
[defaults synchronize];
It doesn't work because you want to store nsdictionary with nsarray with custom object (firstUser) but NSUserDefaults doesn't allow you to store custom object.
Hope this help
//Extended
By saveForKey: and newUseFromKey: I mean something like that:
+(void)saveForKey:(NSString*)key
{
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:self.userName forKey:[NSString stringWithFormat:#"%#_USERNAME", key]];
[defaults setObject:self.password forKey:[NSString stringWithFormat:#"%#_PASSWORD", key]];
//.... other properties
[defaults synchronize];
}
+(newUser)newUseFromKey:(NSString*)key
{
newUser * user = [[newUser alloc] init];
NSUserDefaults * defaults = [NSUserDefaults standardUserDefaults];
user.userName = [defaults objectForKey:[NSString stringWithFormat:#"%#_USERNAME", key]];
user.password = [defaults objectForKey:[NSString stringWithFormat:#"%#_PASSWORD", key]];
//.... other properties
return user;
}
It's good solution if you don't store too many newUser object and if they don't have too many properties.
The best option is put all of your object to array/dictionary (It's up to you, there is no best option between this two) and save it to file. Just remember that if you want to save custom object to file system you have to implement NSCoding protocol.