Cannot get NFC write work on NativeScript 7 or 8

Question

I forked the plugin nativescript-nfc and implemented the NFC write feature for iOS, it works well when using NativeScript 6. But if I upgrade the plugin to 7 or 8, the writing doesn't work, NFCNDEFTag.prototype.queryNDEFStatusWithCompletionHandler is always undefined.

The implementation of writing NFC is shown below.

readerSessionDidDetectTags(
    session: NFCNDEFReaderSession,
    tags: NSArray<NFCNDEFTag> | NFCNDEFTag[]
  ): void {
    const tag = tags[0];
    session.connectToTagCompletionHandler(tag, (error: NSError) => {
      console.log("connectToTagCompletionHandler");

      if (error) {
        console.log(error);
        session.invalidateSessionWithErrorMessage("Error connecting to tag.");
        this.errorCallback(error);
        return;
      }

      const ndefTag: NFCNDEFTag = new interop.Reference<NFCNDEFTag>(
        interop.types.id,
        tag
      ).value;

      try {
        NFCNDEFTag.prototype.queryNDEFStatusWithCompletionHandler.call(
          ndefTag,
          (status: NFCNDEFStatus, number: number, error: NSError) => {
            console.log("queryNDEFStatusWithCompletionHandler");

            if (status == NFCNDEFStatus.NotSupported) {
              var errMessage = "Tag is not NDEF compliant.";
              session.invalidateSessionWithErrorMessage(errMessage);
            } else if (status === NFCNDEFStatus.ReadOnly) {
              var errMessage = "Tag is read only.";
              session.invalidateSessionWithErrorMessage(errMessage);
            } else if (status === NFCNDEFStatus.ReadWrite) {
              const ndefMessage = this._owner.get().message;
              NFCNDEFTag.prototype.writeNDEFCompletionHandler.call(
                ndefTag,
                ndefMessage,
                (error: NSError) => {
                  if (error) {
                    console.log(error);
                    session.invalidateSessionWithErrorMessage("Write failed.");
                    this.errorCallback(error);
                  } else {
                    if (
                      ndefMessage.records[0].typeNameFormat ==
                      NFCTypeNameFormat.Empty
                    ) {
                      session.alertMessage = "Erased data from NFC tag.";
                    } else {
                      if (this.options.writeHint) {
                        session.alertMessage = this.options.writeHint;
                      }
                      this.resultCallback(NfcHelper.ndefToJson(ndefMessage));
                    }
                    session.invalidateSession();
                  }
                }
              );
            }
          }
        );
      } catch (e) {
        session.alertMessage = "error";
      }
    });
  }

I'm not sure if I implement it in the correct way for NativeScript 7 or 8, but at least it works on 6, I actually don't believe it's a bug in the NativeScript across both 7 and 8. We used to live with 6 for a long time just for using this plugin, but really need to upgrade to 7 or 8 for the sake of other features.

Any help, suggestion or comment would be highly appreciated!

Below is the repo and branches for different NativeScript versions.

Repo: https://github.com/nordsense/nativescript-nfc

Branch feature/upgrade-nativescript: This is NativeScript 8, only read works

Branch nordsense: This is NativeScript 6 and both read and write work

You can use the demo project to test, set ndef listener is for read and write Text is for write

It looks like that plugin is already compatible with 7+. When you say upgrade the plugin to 7/8 what are you changing? Also, what JavaScript versions are you targeting. If you are using TypeScript targeting es2015+, are you using `ts-patch`? — RcoderNY, Sep 29 '21 at 10:47
@RcoderNY Thanks for your reply, I edited the question so now you can see the whole source code. The original plugin supports 7+ without writing feature, I implemented the write part based on version 4.1 which is NS 6. When upgrading to 7/8, I basically rebased from version 5.0 and added my implementation. I added `@NativeClass` and also use `ts-patch` — Han, Sep 30 '21 at 13:30

score 0 · Accepted Answer · answered Oct 26 '21 at 07:51

I managed to get it working on NS 8. Referring to the below code snippet, if NFCNDEFTag.prototype is accessed before line 2, like the code in line 1 or by using console.dir(NFCNDEFTag.prototype), line 3 will dump the correct data that belongs to the correct protocol NFCNDEFTag, the remaining code also works well ; if commenting out line 1, line 3 will dump incorrect data which belongs to some other protocols/objects like NSKeyValueCoding and UIAccessibilityAction. I still don't know why this happens, feel like a NativeScript issue, I filed an issue here https://github.com/NativeScript/NativeScript/issues/9609

I rebuilt the plugin and published the package here https://github.com/cloudhx/nativescript-plugins

readerSessionDidDetectTags(session: NFCNDEFReaderSession, tags: NSArray<NFCNDEFTag> | NFCNDEFTag[]): void {
    const prototype = NFCNDEFTag.prototype; // Line 1
    const tag = (<NSArray<NFCNDEFTag>>tags).firstObject; // Line 2
    console.dir(NFCNDEFTag.prototype); // Line 3

    session.connectToTagCompletionHandler(tag, (error: NSError) => {
      console.log('connectToTagCompletionHandler');

      if (error) {
        console.log(error);
        session.invalidateSessionWithErrorMessage('Unable to connect to tag.');
        this.errorCallback(error);
        return;
      }

      const ndefTag: NFCNDEFTag = new interop.Reference<NFCNDEFTag>(interop.types.id, tag).value;

      try {
        NFCNDEFTag.prototype.queryNDEFStatusWithCompletionHandler.call(ndefTag, (status: NFCNDEFStatus, number: number, error: NSError) => {
          console.log('queryNDEFStatusWithCompletionHandler');
// Code omitted for brevity

Cannot get NFC write work on NativeScript 7 or 8

1 Answers1