Define a global color

Question

I want to define a global colour that I can reuse for a downstate for various custom ui cells

Not sure if this is the correct way to do this but..

I've defined a Class called lightGreyUIColor which has this .h file -

#import <UIKit/UIKit.h>

@interface lightGreyUIColor : UIColor
+ (UIColor*)lightGreyBGColor;

@end

and this . m file -

#import "lightGreyUIColor.h"

@implementation lightGreyUIColor

+ (UIColor*)lightGreyBGColor {
return [UIColor colorWithRed:241.0/255.0 green:241/255.0 blue:241/255.0 alpha:1];
}

@end

I have included the lightGreyUIColor.h file in the implementation file for the tableview and tried to reference it as folows -

        cell.backgroundColor = [UIColor lightGreyBGColor];

Which just produces a no known class or method error for lightgreyBGColor, where am I going wrong and is there a better way to implement a global style than this?

Answer 1

You should create a category, not a subclass. This will extend the UIColor class, and add your colors to it.

.h

#import <UIKit/UIKit.h>

@interface UIColor (CustomColors)

+ (UIColor *)myColorLightGreyBGColor;

@end

.m

#import "UIColor+CustomColors.h"

@implementation UIColor (CustomColors)



+ (UIColor *)myColorLightGreyBGColor {

    static UIColor *lightGreyBGColor;

    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        lightGreyBGColor = [UIColor colorWithRed:241.0 / 255.0 
                                           green:241.0 / 255.0
                                            blue:241.0 / 255.0 
                                           alpha:1.0];
    });

    return lightGreyBGColor;
}

@end

By defining your colors this way, and #importing the category, you can apply this custom color the way you were already trying to.

Answer 2

How about a macro?

#define DEFAULT_COLOR_BLUE [UIColor colorWithRed:.196 green:0.3098 blue:0.52 alpha:1.0]

Put it in your appname_Prefix.pch file or more likely a header file included in your prefix file

And it will be like:

cell.backgroundColor = DEFAULT_COLOR_BLUE;