问题
As known, it is not possible to include the interface header file from a file in the -Header.h. My actual problem is that I have the definition of a class one protocol of which is a Swift one:
@protocol arrivingDelegate;
@interface palettaTraffic : NSObject<MKMapViewDelegate, arrivingDelegate> {
}
If I import the *-Swift.h file I get into the ugly cycle when the file is included in another one that is included in the header file.
This is what happens when I use the @protocol directive: it is a warning, but quite a disturbing one.
This is how the swift protocol is defined:
@objc public protocol arrivingDelegate {
func submitManualBusLine(busStripe:StripeProtocol)
}
I also found a similar post: Swift protocol in Objective-C class
But none of the suggestions seem to apply.
回答1:
If I import the *-Swift.h file I get into the ugly cycle when the file is included in another one that is included in the header file.
Okay, but that is what you have to do. I don't see you doing it the screen shot above, which is why your protocol is not being seen.
The solution to the "ugly cycle" should be just a matter of tweaking the order in which things are imported in your various Objective-C files.
回答2:
Adopting swift protocols in Objective-c is a tricky process. I fixed the issue by porting the adopting class to Swift too.
回答3:
What I tend to do in my projects is putting the protocol conformance of the ObjC class in a Swift file, to avoid this error. Usually the file where the protocol is defined.
extension PalettaTraffic: ArrivingDelegate {}
Why? We're migrating our codebase from ObjC to Swift, but we cannot migrate every class at the same time. Because of this we have a large 'seem' between Swift & ObjC where Swift types need ObjC and vice versa. For me, this is the solution that causes the least amount of work right away.
来源：https://stackoverflow.com/questions/31629825/short-circuit-when-using-a-swift-protocol