How to save custom color to UserDefaults - uicolor

Question

I am trying to use some non-standard colors (i.e. not UIColor blueColor, but a darker blue color, a darker green, red...etc...) and when I try to save the user selected UIColor object to UserDefaults, it is failing. Below is the code I am using to create the custom colors, followed by the code to save the UIColor objects to the UserDefaults.
Any help would be appreciated.
Thanks!
// create the custom color
UIColor *selectedColor = [UIColor colorWithRed:0.0 green:0.5 blue:0.0 alpha:1.0];
// save the color to user defaults
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
// archive it into a data object
/*** Fails on this next line ***/
NSData *dataColor = [NSKeyedArchiver archivedDataWithRootObject: selectedColor];
// write the data into the user defaults
[prefs setObject: dataColor forKey:colorKey];
[prefs synchronize];

Answer 1

The problem here is that UIColor is not "key-coding" compliant (I am not sure about the correct term), you should have an error like this:
*** -[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value
It cannot be saved into NSUSerDefaults, you need to saved them using a NSKeyArchiver or convert the color values in to something key-code compliant. For example I have followed the NSStringFromCGRect approach using categories. This is my code:
UIColorAdditions.h
#import <Foundation/Foundation.h>
#interface UIColor (UIColorAdditions)
+ (NSString *)stringFromUIColor:(UIColor *)color;
#end
#interface NSString (UIColorAdditions)
+ (UIColor *)colorFromNSString:(NSString *)string;
#end
UIColorAdditions.m
#import "UIColorAdditions.h"
#implementation UIColor (UIColorAdditions)
+ (NSString *)stringFromUIColor:(UIColor *)color {
return [NSString stringWithFormat:#"%#", color ];
}
#end
#implementation NSString (UIColorAdditions)
+ (UIColor*)colorFromNSString:(NSString *)string {
// The string should be something like "UIDeviceRGBColorSpace 0.5 0 0.25 1
NSArray *values = [string componentsSeparatedByString:#" "];
CGFloat red = [[values objectAtIndex:1] floatValue];
CGFloat green = [[values objectAtIndex:2] floatValue];
CGFloat blue = [[values objectAtIndex:3] floatValue];
CGFloat alpha = [[values objectAtIndex:4] floatValue];
UIColor *color = [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
return color;
}
#end
An example of use:
NSString *strColor = [UIColor stringFromUIColor:[UIColor colorWithRed:0.5 green:0 blue:0.25 alpha:1.0]];
[[NSUserDefaults standardUserDefaults] setObject:strColor forKey:kViewBgColorKey];
There are multiple solutions, (better ones), I just posted mine.