Swift 由十六进制转为RGB的颜色设置

如果美工给你的颜色值或者后台取到的颜色值为十六进制时，如：

#3492e9

UIColor中没有直接以十六进制色值数为参数的方法，如下可以转为RGB，alpha也可以设定：

 1 func colorConversion (Color_Value:NSString, alpha: CGFloat)->UIColor{
 2         var  Str :NSString = Color_Value.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
 3         if Color_Value.hasPrefix("#"){
 4             Str=(Color_Value as NSString).substringFromIndex(1)
 5         }
 6         let redStr = (Str as NSString ).substringToIndex(2)
 7         let greenStr = ((Str as NSString).substringFromIndex(2) as NSString).substringToIndex(2)
 8         let blueStr = ((Str as NSString).substringFromIndex(4) as NSString).substringToIndex(2)
 9         var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0;
10         NSScanner(string:redStr).scanHexInt(&r)
11         NSScanner(string: greenStr).scanHexInt(&g)
12         NSScanner(string: blueStr).scanHexInt(&b)
13         return UIColor(red: CGFloat(r)/255.0, green: CGFloat(g)/255.0, blue: CGFloat(b)/255.0, alpha: alpha)
14     }

然后调用这个方法来设置颜色就ok了：

self.backgroundColor = colorConversion("#3492e9", alpha: 1.0)