Can not find Swift Protocol declaration in Obj-C class

Question

I have created on Class in Swift and that class and its protocol I am using in Obj-C enabled project but I am getting below error while compiling my project.

cannot find protocol declaration for 'SpeechRecognizerDelegate'; did you mean 'SFSpeechRecognizerDelegate'?

Can anyone guide me on this how can I use Swift class protocol in my Obj-C class.

Here is my Swift code:

protocol SpeechRecognizerDelegate : class  {
    func speechRecognitionFinished(_ transcription:String)
    func speechRecognitionError(_ error:Error)
}


class SpeechRecognizer: NSObject, SFSpeechRecognizerDelegate {
    open weak var delegate: SpeechRecognizerDelegate?

}

Protocol use in Obj-C:

#import "ARBot-Swift.h"

@interface ChatScreenViewController : JSQMessagesViewController <SpeechRecognizerDelegate>

Let me know if required more info.

Thanks in Advance.

Answer 1

Define your Swift protocol like this inside your Swift file.

@objc protocol SpeechRecognizerDelegate: class{
  func speechRecognitionFinished(_ transcription:String)
  func speechRecognitionError(_ error:Error)
}

Create a Swift Module inside your project setting then use it. You can find here complete blog for the mix language coding.

Then use Protocol inside Objective C class,

We required to add protocol inside Objective C file -

#import "ARBot-Swift.h"

@interface ChatScreenViewController : JSQMessagesViewController <SpeechRecognizerDelegate>

---

Then you need to conform to the protocol methods -

- (void)viewDidLoad {
    [super viewDidLoad];
    SpeechRecognizer * speechRecognizer = [[SpeechRecognizer alloc] init];
    speechRecognizer.delegate = self;
}


#pragma mark - Delegate Methods
-(void)speechRecognitionFinished:(NSString *) transcription{
   //Do something here
}

-(void)speechRecognitionError:(NSError *) error{
   //Do something here
}