swift中的枚举：
enum CompassPoint {
case North
case South
case East
case West
}
swift中的宏定义：
public let ScreenWidth = UIScreen.mainScreen().bounds.size.width
public let ScreenHeight = UIScreen.mainScreen().bounds.size.height
public let MainBounds = UIScreen.mainScreen().bounds
public let globalTabbarHeight = 49
public let globalNavigationBarHeight = 64
注：public可加可不加
如果有参数：
func RGBCOLOR(r:CGFloat,_ g:CGFloat,_ b:CGFloat) -> UIColor
{
return UIColor(red: (r)/255.0, green: (g)/255.0, blue: (b)/255.0, alpha: 1.0)
}
