Objective-C save NSColor in NSUserDefaults

How do you save the color of the dot so that when the app is opened and closed the dot is the color it was last set to by the user?

Could someone explain to me how to use NSUserDefaults and in which methods to declare NSUserDefaults.

So far i have this:

NSData *data = [NSArchiver archivedDataWithRootObject:color];
[[NSUserDefaults standardUserDefaults] setObject:data forKey:@"MyColor"];

N开发者_如何学编程SData *data = [[NSUserDefaults standardUserDefaults] objectForKey:@"MyColor"];
NSColor *color = [NSUnarchiver unarchiveObjectWithData:data];

Link for tutorial I followed: http://www.mactech.com/articles/mactech/Vol.25/25.04/2504RoadtoCode/index.html

This is what I use:

- (NSColor *)colorForKey:(NSString *)key
{
    NSData  *data;
    NSColor *color;

    data = [[NSUserDefaults standardUserDefaults] objectForKey:key];
    color= [NSUnarchiver unarchiveObjectWithData:data];
    if( ! [color isKindOfClass:[NSColor class]] )
    {
        color = nil;
    }

    return color;
    }

- (void)setColor:(NSColor *)color forKey:(NSString *)key
{
    NSData *data = [NSArchiver archivedDataWithRootObject:color];
    [[NSUserDefaults standardUserDefaults] setObject:data forKey:key];

    [BFChatWindow refresh];
}