ios - 如何从 Objective C 项目 App Delegate 调用 Swift？

Question

此代码来自 Swift 项目 App 委托(delegate)。它用于帮助使用可发布的 key 配置 Stripe。

//Appdelegate.swift
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: 
[UIApplicationLaunchOptionsKey: Any]?) -> Bool 
{
//The code helps configure Stripe with a publishable key.
STPPaymentConfiguration.shared().publishableKey = Constants.publishableKey
...
}

将 Swift 行添加到 Objective C App Delegate 后构建应用程序时显示两个错误

//AppDelegate.h
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions
{
STPPaymentConfiguration.shared().publishableKey = Constants.publishableKey

Property 'shared' not found on object of type 'STPPaymentConfiguration'
Use of undeclared identifier 'Constants'

这是在 @objc 之前编译时出现的类似错误。已添加到演示 Swift 函数 MockApiClient。它应该添加到其他地方吗？我试过添加 @objc到这里的答案中提到的枚举无济于事。

//Constants.swift 
//This is the file the original Swift app delegate accesses
import Foundation

  enum Constants {
  static let publishableKey = "pk_live_..."
  static let baseURLString = "http://54.33.123.227:1234"
  static let defaultCurrency = "usd"
  static let defaultDescription = "Receipt" //change to describe actual app & charge
  }

采取的步骤:

打开 Objective C 项目并创建一个桥接头

在仍然在 Obj C 项目中时在 Swift 中创建了一个演示类，以确保可以使用它，在这种情况下，在加载 View 时从 Objective C 文件中打印。具体派生自一个 NSObject。将覆盖添加到初始化程序并使用 @objc字首。

//  MockApiClient.swift
import Foundation
class MockApiClient: NSObject
{
override init()
{
print("Initializer called in Mock API client")
}
@objc func executeRequest()
{
print("The execute request has been called in the Mock API Client")
}
}

//ViewController.h
//Prints the Swift request written in the MockApiClient the the view loads

@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
MockApiClient *client = [MockApiClient new];
[client executeRequest];
}

已复制#import "ViewController.h"导入自动生成的project-Bridging-Header.h文件以将其中的Objective C公开给swift

将必要的 Swift 文件添加到 Objective C 项目，以便 Constants.publishablekey来自 Constants.swift 的数据能够被找到的

如何将此 Swift App 委托(delegate)代码添加到 Objective C 项目的 App 委托(delegate)中？
编辑:添加 @objc 时出错到 enum Constants.swift 中的声明

Answer 1

Edit: error when adding @objc to the enum declaration in Constants.swift

用作命名空间的 Swift 枚举不能暴露给 Objective-C。
您可能需要使用 class使其适用于 Swift 和 Objective-C:

@objcMembers
class Constants: NSObject {
    static let publishableKey = "pk_live_..."
    static let baseURLString = "http://54.33.123.227:1234"
    static let defaultCurrency = "usd"
    static let defaultDescription = "Receipt" //change to describe actual app & charge
    
    private override init() {}
}