我最近发现了在 Swift 中创建等效 NS_OPTIONS 的方法，但是我无法在 Objective-C/Swift 项目中从 Objective-C 代码中使用它们。

这是我做的一个示例项目:

ObjcObject.h & ObjcObject.m

typedef NS_OPTIONS(NSUInteger, MyObjcOption)
{
    MyOptionNone = 0,
    MyObjcOptionCase01  = 1 << 0,
    MyObjcOptionCase02  = 1 << 1,
    MyObjcOptionCaseAll = MyObjcOptionCase01 | MyObjcOptionCase02
};

@interface ObjcObject : NSObject

+ (void)printMyObjcOption:(MyObjcOption)option;

@end

@implementation ObjcObject

+ (void)printMyObjcOption:(MyObjcOption)option
{
    if (option == 0)
        NSLog(@"None");

    if (option & MyObjcOptionCase01)
        NSLog(@"MyObjcOptionCase01");

    if (option & MyObjcOptionCase02)
        NSLog(@"MyObjcOptionCase02");
}

@end

SwiftObject.swift

struct MySwiftOption: RawOptionSetType, BooleanType {
    private var value: UInt = 0
    var rawValue: UInt { return self.value }

    init(_ value: UInt)         { self.value = value }
    init(rawValue value: UInt)  { self.value = value }
    init(nilLiteral: ())        { self.value = 0 }

    var boolValue: Bool { return value != 0 }

    static var allZeros: MySwiftOption  { return self(0) }
    static var None: MySwiftOption      { return self(0) }
    static var All: MySwiftOption       { return self.Case01 | self.Case02 }

    static var Case01: MySwiftOption    { return self(1 << 0) }
    static var Case02: MySwiftOption    { return self(1 << 1) }
}

public class SwiftObject: NSObject {
    class func printMySwiftOption(option: MySwiftOption) {
        if option.rawValue == 0 {
            println("None")
        }

        if option & MySwiftOption.Case01 {
            println(".Case01")
        }

        if option & MySwiftOption.Case02 {
            println(".Case02")
        }
    }

    class func sayHello() {
        println("Hello")
    }
}

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    MyObjcOption objcOption = MyObjcOptionCase02;
    [ObjcObject printMyObjcOption:objcOption];

    [SwiftObject sayHello];
//    MySwiftOption swiftOption = MySwiftOptionCase02; // Error: Use of undeclared identifier 'MySwiftOption'
//    [SwiftObject printMySwiftOption:swiftOption];

    return YES;
}

在 Objective-C 代码中，我总是收到错误 Use of undeclared identifier 'MySwiftOption'。

这是一个已知问题吗？有解决方法吗？

最佳答案

您不能将结构从 Swift 公开给 ObjectiveC。实际上，查看 -Swift.h 文件，看看您可以从 Objective 访问什么。你不会在那里找到 MySwiftOptions。

You’ll have access to anything within a class or protocol that’s marked with the @objc attribute as long as it’s compatible with Objective-C. This excludes Swift-only features such as those listed here:

Generics Tuples,

Enumerations defined in Swift,

Structures defined in Swift,

Top-level functions defined in Swift,

Global variables defined in Swift,

Typealiases defined in Swift,

Swift-style variadics Nested types,

Curried functions

我，例如，每天都生活在这些限制之中。

Using Swift with Cocoa and Objective-C at Apple.

关于ios - RawOptionSetType 兼容 Objective-C 吗？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30701812/