在Objc中定义的枚举>在Swift中声明>在Objc中使用

Question

I have a situation. I would appreciated if anyone has a solution for this

• I have an objC enum say Abc
• I declare this in a swift class, say, MySwiftClass.swift as var abc : Abc!
• I have created an instance of MySwiftClass ( mySwiftClass ) in another ObjC class (myObjC.m file)
• In myObjC.m, I'm trying to access enum Abc as mySwiftClass.abc .

This is throwing an error - “Property 'abc' not found on object of type MySwiftClass *”. Basically the enum is not added as property in the “ProjectName-Swift.h” file.

What I believe is happening is that when I'm declaring the ObjC enum in Swift class, it is getting converted to a swift enum and hence I'm not able to access it in ObjC file.

Note: Marking the Swift class as @objc did not work.

Answer 1

Numeric Swift optionals cannot be represented in Objective-C, and thus will not be exposed to Objective-C. Declare abc to not be optional and it should be available from Objective-C.

Consider this Objective-C enumeration:

typedef NS_ENUM(NSInteger, Foo) {
    FooBar,
    FooBaz,
    FooQux
};

Then consider this Swift 3 class:

class SomeObject: NSObject {
    var foo1: Foo  = .bar          // this is exposed to Objective-C
    var foo2: Foo! = .bar          // this is not
}

The non-optional, foo1 , will be exposed to Objective-C, whereas the optional, foo2 , will not.