如何在另一个Swift类中访问常量值

Question

how to get constant #define value in swift class. I have created constant.h class in my project, here I created the screen width and hight two constants values.

Constant.h

#define SCREEN_WIDTH_SWIFT          UIScreen.main.bounds.size.width
#define SCREEN_HEIGHT_SWIFT         UIScreen.main.bounds.size.height

Now i want to asses SCREEN_HEIGHT_SWIFT in ViewController.swift class

NSFontAttributeName : UIFont(name: "GillSans-Light" , size: MS_SCREEN_HEIGHT_SWIFT/40.5)!,NSForegroundColorAttributeName : UIColor.white

Answer 1

#define creates a C style compiler macro, not a constant. Swift doesn't support C compiler macros. You will need to use an actual constant.

Answer 2

Hi instead of using #define use let and assign the values with a = :

let SCREEN_WIDTH_SWIFT = UIScreen.main.bounds.size.width
let SCREEN_HEIGHT_SWIFT = UIScreen.main.bounds.size.height

Answer 3

Simply create separate class to maintain your all constants. Lets say AppConstats is your class. Then create your constants like this:

static let SCREEN_WIDTH = UIScreen.main.bounds.size.width

Now wherever you want to access your constant, simply use like this:

AppConstats.SCREEN_WIDTH