Using [UIColor colorWithRed:green:blue:alpha:] doesn't work with UITableView seperatorColor?

Question

I'm trying to configure a dark gray seperator color. Why does the following do nothing?

self.tableView.seperatorStyle = UITableViewCellSeperatorStyleSingleLine;
self.tableView.seperatorColor = [UIColor colorWithRed: 127 green:127 blue:127 alpha:1];

returns a table with no seperators at all.

As soon as I use [UIColor blackColor] then I get seperators just fine. What's the deal?

Answer 1

You need to divide by 255.0

Because I hardly ever use values between 1.0 and 0.0, I created a very simple UIColor category that does the messy looking division by itself: (from http://github.com/Jon889/JPGeneral)

//.h file
@interface UIColor (JPExtras)
+ (UIColor *)colorWithR:(CGFloat)red G:(CGFloat)green B:(CGFloat)blue A:(CGFloat)alpha;
@end

//.m file
@implementation UIColor (JPExtras)
+ (UIColor *)colorWithR:(CGFloat)red G:(CGFloat)green B:(CGFloat)blue A:(CGFloat)alpha {
    return [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:alpha];
}
@end

So you can just do(If you import the category I linked to above):

[UIColor colorWithR:127 G:127: B:127 A:1];

Answer 2

Because your UIColor method requires a float from 0-1, not 0-255. You need to divide all your RGB values by 255.0, as follows:

self.tableView.seperatorColor = [UIColor colorWithRed:127.0f/255.0f green:127.0f/255.0f blue:127.0f/255.0f alpha:1.0f];

Answer 3

You have to divide your values with 255, because the range is 0-1. Take 127/255 = 0.49f and type in that instead. It's there, it's just white :)

edit: cause of comments, I added some code as to how I solve it:

-(float)getRGBValue:(int) rgbValue{  
    return rgbValue/255.0;
]

Answer 4

There are two new methods in UIColor that accept integer values from 0 to 255:

UIColor(red: Int, green: Int, blue: Int)

and

UIColor(alpha: Float, red: Int, green: Int, blue: Int)

It's not in the documentation but I've used it and it works like a charm.