UIColor from Hex in Monotouch - uikit

Question

How to get a UIColor from an hex value in Monotouch?

Answer 1

I found some solutions for Objective C and none specifically for Monotouch I ended up developing an extension method based on the most popular solution for IOS:
public static class UIColorExtensions
{
public static UIColor FromHex(this UIColor color,int hexValue)
{
return UIColor.FromRGB(
(((float)((hexValue & 0xFF0000) >> 16))/255.0f),
(((float)((hexValue & 0xFF00) >> 8))/255.0f),
(((float)(hexValue & 0xFF))/255.0f)
);
}
}
and use it like this:
new UIColor().FromHex(0x4F6176);
Update, it seems that as off Monotouch 5.4 UIColor does not have a parameterless constructor so use it like this:
UIColor.Clear.FromHex(0xD12229);

Answer 2

Maybe this helps you, if you are using Xamarin.Forms:
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
...
Color.FromHex("#00FF00").ToUIColor();

Answer 3

Here one that lets you use a string like in css:
UIColor textColorNormal = UIColor.Clear.FromHexString("#f4f28d", 1.0f);
And here is the class:
using System;
using System.Drawing;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using System.Globalization;
namespace YourApp
{
public static class UIColorExtensions
{
public static UIColor FromHexString (this UIColor color, string hexValue, float alpha = 1.0f)
{
var colorString = hexValue.Replace ("#", "");
if (alpha > 1.0f) {
alpha = 1.0f;
} else if (alpha < 0.0f) {
alpha = 0.0f;
}
float red, green, blue;
switch (colorString.Length)
{
case 3 : // #RGB
{
red = Convert.ToInt32(string.Format("{0}{0}", colorString.Substring(0, 1)), 16) / 255f;
green = Convert.ToInt32(string.Format("{0}{0}", colorString.Substring(1, 1)), 16) / 255f;
blue = Convert.ToInt32(string.Format("{0}{0}", colorString.Substring(2, 1)), 16) / 255f;
return UIColor.FromRGBA(red, green, blue, alpha);
}
case 6 : // #RRGGBB
{
red = Convert.ToInt32(colorString.Substring(0, 2), 16) / 255f;
green = Convert.ToInt32(colorString.Substring(2, 2), 16) / 255f;
blue = Convert.ToInt32(colorString.Substring(4, 2), 16) / 255f;
return UIColor.FromRGBA(red, green, blue, alpha);
}
default :
throw new ArgumentOutOfRangeException(string.Format("Invalid color value {0} is invalid. It should be a hex value of the form #RBG, #RRGGBB", hexValue));
}
}
}
}

Answer 4

As an option, for example
public static UIColor FromHEX(string hex)
{
int r = 0, g = 0, b = 0, a = 0;
if (hex.Contains("#"))
hex = hex.Replace("#", "");
switch (hex.Length)
{
case 2:
r = int.Parse(hex, System.Globalization.NumberStyles.AllowHexSpecifier);
g = int.Parse(hex, System.Globalization.NumberStyles.AllowHexSpecifier);
b = int.Parse(hex, System.Globalization.NumberStyles.AllowHexSpecifier);
a = 255;
break;
case 3:
r = int.Parse(hex.Substring(0, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
g = int.Parse(hex.Substring(1, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
b = int.Parse(hex.Substring(2, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
a = 255;
break;
case 4:
r = int.Parse(hex.Substring(0, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
g = int.Parse(hex.Substring(1, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
b = int.Parse(hex.Substring(2, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
a = int.Parse(hex.Substring(3, 1), System.Globalization.NumberStyles.AllowHexSpecifier);
break;
case 6:
r = int.Parse(hex.Substring(0, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
g = int.Parse(hex.Substring(2, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
b = int.Parse(hex.Substring(4, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
a = 255;
break;
case 8:
r = int.Parse(hex.Substring(0, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
g = int.Parse(hex.Substring(2, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
b = int.Parse(hex.Substring(4, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
a = int.Parse(hex.Substring(6, 2), System.Globalization.NumberStyles.AllowHexSpecifier);
break;
}
return UIColor.FromRGBA(r, g, b, a);
}
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