iOS 十六进制转RGB

+ (UIColor *)colorWithRGBHex:(UInt32)hex
{
    return [UIColor colorWithRGBHex:hex alpha:1.0f];
}

+ (UIColor *)colorWithRGBHex:(UInt32)hex alpha:(CGFloat)alpha
{
    int r = (hex >> 16) & 0xFF;
    int g = (hex >> 8) & 0xFF;
    int b = (hex) & 0xFF;

    return [UIColor colorWithRed:r / 255.0f green:g / 255.0f blue:b / 255.0f alpha:alpha];
}