Global constants file in Swift
I am abit late to the party.
No matter here's how i manage the constants file so that it makes more sense to developers while writing code in swift.
FOR URL:
//URLConstants.swift
struct APPURL {
private struct Domains {
static let Dev = "http://test-dev.cloudapp.net"
static let UAT = "http://test-UAT.com"
static let Local = "192.145.1.1"
static let QA = "testAddress.qa.com"
}
private struct Routes {
static let Api = "/api/mobile"
}
private static let Domain = Domains.Dev
private static let Route = Routes.Api
private static let BaseURL = Domain + Route
static var FacebookLogin: String {
return BaseURL + "/auth/facebook"
}
}
For CUSTOMFONTS:
//FontsConstants.swift
struct FontNames {
static let LatoName = "Lato"
struct Lato {
static let LatoBold = "Lato-Bold"
static let LatoMedium = "Lato-Medium"
static let LatoRegular = "Lato-Regular"
static let LatoExtraBold = "Lato-ExtraBold"
}
}
FOR ALL THE KEYS USED IN APP
//KeyConstants.swift
struct Key {
static let DeviceType = "iOS"
struct Beacon{
static let ONEXUUID = "xxxx-xxxx-xxxx-xxxx"
}
struct UserDefaults {
static let k_App_Running_FirstTime = "userRunningAppFirstTime"
}
struct Headers {
static let Authorization = "Authorization"
static let ContentType = "Content-Type"
}
struct Google{
static let placesKey = "some key here"//for photos
static let serverKey = "some key here"
}
struct ErrorMessage{
static let listNotFound = "ERROR_LIST_NOT_FOUND"
static let validationError = "ERROR_VALIDATION"
}
}
FOR COLOR CONSTANTS:
//ColorConstants.swift
struct AppColor {
private struct Alphas {
static let Opaque = CGFloat(1)
static let SemiOpaque = CGFloat(0.8)
static let SemiTransparent = CGFloat(0.5)
static let Transparent = CGFloat(0.3)
}
static let appPrimaryColor = UIColor.white.withAlphaComponent(Alphas.SemiOpaque)
static let appSecondaryColor = UIColor.blue.withAlphaComponent(Alphas.Opaque)
struct TextColors {
static let Error = AppColor.appSecondaryColor
static let Success = UIColor(red: 0.1303, green: 0.9915, blue: 0.0233, alpha: Alphas.Opaque)
}
struct TabBarColors{
static let Selected = UIColor.white
static let NotSelected = UIColor.black
}
struct OverlayColor {
static let SemiTransparentBlack = UIColor.black.withAlphaComponent(Alphas.Transparent)
static let SemiOpaque = UIColor.black.withAlphaComponent(Alphas.SemiOpaque)
static let demoOverlay = UIColor.black.withAlphaComponent(0.6)
}
}
You can wrap these all files in a common group named Constants in your Xcode Project.
And for more watch this video
Although I prefer @Francescu's way (using a struct with static properties), you can also define global constants and variables:
let someNotification = "TEST"
Note however that differently from local variables/constants and class/struct properties, globals are implicitly lazy, which means they are initialized when they are accessed for the first time.
Suggested reading: Global and Local Variables, and also Global variables in Swift are not variables
Structs as namespace
IMO the best way to deal with that type of constants is to create a Struct.
struct Constants {
static let someNotification = "TEST"
}
Then, for example, call it like this in your code:
print(Constants.someNotification)
Nesting
If you want a better organization I advise you to use segmented sub structs
struct K {
struct NotificationKey {
static let Welcome = "kWelcomeNotif"
}
struct Path {
static let Documents = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
static let Tmp = NSTemporaryDirectory()
}
}
Then you can just use for instance K.Path.Tmp
Real world example
This is just a technical solution, the actual implementation in my code looks more like:
struct GraphicColors {
static let grayDark = UIColor(0.2)
static let grayUltraDark = UIColor(0.1)
static let brown = UIColor(rgb: 126, 99, 89)
// etc.
}
and
enum Env: String {
case debug
case testFlight
case appStore
}
struct App {
struct Folders {
static let documents: NSString = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString
static let temporary: NSString = NSTemporaryDirectory() as NSString
}
static let version: String = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as! String
static let build: String = Bundle.main.object(forInfoDictionaryKey: "CFBundleVersion") as! String
// This is private because the use of 'appConfiguration' is preferred.
private static let isTestFlight = Bundle.main.appStoreReceiptURL?.lastPathComponent == "sandboxReceipt"
// This can be used to add debug statements.
static var isDebug: Bool {
#if DEBUG
return true
#else
return false
#endif
}
static var env: Env {
if isDebug {
return .debug
} else if isTestFlight {
return .testFlight
} else {
return .appStore
}
}
}