单色的Hex中的UIColor

Question

如何从Monotouch中的十六进制值获取UIColor？

Answer 1

我找到了针对Objective C的一些解决方案，没有专门针对Monotouch的解决方案我最终开发了一种基于最流行的IOS解决方案的扩展方法：

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)
            );
        }
    }

并像这样使用它：

new UIColor().FromHex(0x4F6176);

更新，似乎关闭Monotouch 5.4 UIColor没有无参数构造函数，所以像这样使用它：

 UIColor.Clear.FromHex(0xD12229);

Answer 2

这里允许你使用css中的字符串：

UIColor textColorNormal = UIColor.Clear.FromHexString("#f4f28d", 1.0f);

这是班级：

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 3

如果您使用的是Xamarin.Forms，可能这对您有所帮助：

using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

...
Color.FromHex("#00FF00").ToUIColor();

Answer 4

作为选项，例如

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);
    }

xamarin.ios uicolor colorhelper