在我的Objective-C项目中，我经常使用一个全局常量文件来存储像通知名称和NSUserDefaults键这样的东西。它看起来是这样的:
@interface GlobalConstants : NSObject
extern NSString *someNotification;
@end
@implementation GlobalConstants
NSString *someNotification = @"aaaaNotification";
@end
我如何在Swift中做完全相同的事情?
当前回答
Constant.swift
import Foundation
let kBaseURL = NSURL(string: "http://www.example.com/")
ViewController.swift
var manager = AFHTTPRequestOperationManager(baseURL: kBaseURL)
其他回答
也可以使用无大小写枚举。
优点-它们不能被实例化。
enum API {
enum Endpoint {
static let url1 = "url1"
static let url2 = "url2"
}
enum BaseURL {
static let dev = "dev"
static let prod = "prod"
}
}
颜色
extension UIColor {
static var greenLaPalma: UIColor {
return UIColor(red:0.28, green:0.56, blue:0.22, alpha:1.00)
}
}
字体
enum CustomFontType: String {
case avenirNextRegular = "AvenirNext-Regular",
avenirDemiBold = "AvenirNext-DemiBold"
}
extension UIFont {
static func getFont(with type: CustomFontType, size: CGFloat) -> UIFont {
let font = UIFont(name: type.rawValue, size: size)!
return font
}
}
对于其他-一切都与接受的答案相同。
结构作为命名空间
在我看来，处理这类常量的最好方法是创建一个Struct。
struct Constants {
static let someNotification = "TEST"
}
然后，例如，在你的代码中这样调用它:
print(Constants.someNotification)
嵌套
如果你想要一个更好的组织，我建议你使用分段子结构
struct K {
struct NotificationKey {
static let Welcome = "kWelcomeNotif"
}
struct Path {
static let Documents = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
static let Tmp = NSTemporaryDirectory()
}
}
然后您可以使用实例K.Path.Tmp
现实世界的例子
这只是一个技术解决方案，在我的代码中的实际实现看起来更像:
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
}
}
}
为了在我的应用程序中有全局常量，这是我在一个单独的Swift文件中所做的:
import Foundation
struct Config {
static let baseURL = "https://api.com"
static APIKeys {
static let token = "token"
static let user = "user"
}
struct Notifications {
static let awareUser = "aware_user"
}
}
它很容易使用，并且可以像这样调用任何地方:
print(Config.Notifications.awareUser)
向苹果学习是最好的方法。
例如，苹果的键盘通知:
extension UIResponder {
public class let keyboardWillShowNotification: NSNotification.Name
public class let keyboardDidShowNotification: NSNotification.Name
public class let keyboardWillHideNotification: NSNotification.Name
public class let keyboardDidHideNotification: NSNotification.Name
}
现在我向苹果学习:
extension User {
/// user did login notification
static let userDidLogInNotification = Notification.Name(rawValue: "User.userDidLogInNotification")
}
更重要的是，NSAttributedString.Key.foregroundColor:
extension NSAttributedString {
public struct Key : Hashable, Equatable, RawRepresentable {
public init(_ rawValue: String)
public init(rawValue: String)
}
}
extension NSAttributedString.Key {
/************************ Attributes ************************/
@available(iOS 6.0, *)
public static let foregroundColor: NSAttributedString.Key // UIColor, default blackColor
}
现在我向苹果学习:
extension UIFont {
struct Name {
}
}
extension UIFont.Name {
static let SFProText_Heavy = "SFProText-Heavy"
static let SFProText_LightItalic = "SFProText-LightItalic"
static let SFProText_HeavyItalic = "SFProText-HeavyItalic"
}
用法:
let font = UIFont.init(name: UIFont.Name.SFProText_Heavy, size: 20)
向苹果学习是每个人都可以做的事情，可以很容易地提高你的代码质量。
