Have you tried making it non-private? Also, I’m seeing that classes extending Obj-C classes need to ...

# ios

[Jacob Rhoda]

Have you tried making it non-private? Also, I’m seeing that classes extending Obj-C classes need to be final. https://kotlinlang.org/docs/native-objc-interop.html#subclassing-swift-objective-c-classes-and-protocols-from-kotlin

[Giovanni Trenta]

I also have the same error as Carlo, although the func tagReaderSessionDidBecomeActive is called correctly, however the func tagReaderSession(session: NFCTagReaderSession, didDetectTags: List<*>) gives the error “Delegate does not implement -tagReaderSessiondidDetectTags method” .
Could this be a recognized bug?
I read that with swift the delegate implementation code is this “tagReaderSession(_ session: NFCTagReaderSession, didDetect tags: [NFCTag]) ” but in kotlin it is different “tagReaderSession(session: NFCTagReaderSession, didDetectTags: List<*>)”

[Jacob Rhoda]

Ah yeah you might have to change the ObjC name with an annotation. The compiler might be mangling that.

[Jacob Rhoda]

https://kotlinlang.org/docs/native-objc-interop.html#name-translation

[Carlo De Chellis]

Hi, thanks for your time, but:
@ObjCName is not applicable on overrides

[Carlo De Chellis]

ide said

[Jacob Rhoda]

Shoot. Sorry!

[Carlo De Chellis]

any help is appreciated

[Giovanni Trenta]

thanks for the help, any suggestion is welcome, also because I haven’t found any example of using nfc for ios with kotlin multiplatform

[xxfast]

I too encounter the same issue

-[NFCTagReaderSession didDetectTags:connectedTagIndex:]:163 Delegate does not implement -tagReaderSession:didDetectTags: method

But my kotlin delegate looks like

class NFCTagReaderSessionDelegate() : NSObject(), NFCTagReaderSessionDelegateProtocol {
  override fun tagReaderSession(session: NFCTagReaderSession, didDetectTags: List<*>) {
  }
}

[xxfast]

seems to be a compiler issue? 🤔

[xxfast]

Issue is raised here. https://youtrack.jetbrains.com/issue/KT-54114/Kotlin-Multiplatform-iOS-Native-CoreNFC-De[…]e-does-not-implement-tagReaderSessiondidDetectTags-method but was closed for inactivity

[xxfast]

ah so turns out you just need to keep a reference to your delegate

actual class Nfc {
  lateinit var delegate: NFCTagReaderSessionDelegate

  @OptIn(ExperimentalForeignApi::class)
  actual fun ndef(): Flow<NfcDataExchangeFormat> = callbackFlow {
    delegate = NFCTagReaderSessionDelegate(scope = this)
    val session = NFCTagReaderSession(
      pollingOption = NFCPollingISO14443 or NFCPollingISO15693 or NFCPollingISO18092,
      delegate = delegate,
      queue = dispatch_get_main_queue(),
    )
    session.alertMessage = "Hold your iPhone near an NFC tag to pair with the device."
    session.beginSession()
    awaitClose { session.invalidateSession() }
  }
}