Objective C defining UIColor constants

Question

Hi,

I have a iPhone application with a few custom-defined colors for my theme. Since these colors will be fixed for my UI, I would like to define the colors in a class to be included (Constants.h and Constants.m). How do I do that? (Simply defining them does not work because UIColors are mutable, and would cause errors - Initalizer not constant).

/* Constants.h */
extern UIColor *test;

/* Constants.m */
UIColor *test = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1.0];

Thanks!

Answer 1

A UIColor is not mutable. I usually do this with colors, fonts and images. You could easily modify it to use singletons or have a static initializer.

@interface UIColor (MyProject)

+(UIColor *) colorForSomePurpose;

@end

@implementation UIColor (MyProject)

+(UIColor *) colorForSomePurpose { return [UIColor colorWithRed:0.6 green:0.8 blue:1.0 alpha:1.0]; }

@end

Answer 2

Often people put global constants into singleton objects - or as drawnonward noted, you can make them accessible via a class method of some class.

Answer 3

Use the AppController to make the colors accessible globally, rather than a static variable. That way it makes sense from an architecture standpoint, and also if you wanted to hypothetically change color schemes, even while running, this would just be a method or two on the AppController