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：

 

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

然后调用这个方法来设置颜色就ok了：

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