java.lang.StringIndexOutOfBoundsException when writing to a tag

[AntSwift]

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Hi,

Using the example app, without changes, I am hitting a StringIndexOutOfBoundsException exception when attempting to write to a tag. The message has a single record text/plain - Test.

Here is the stack trace:

W/Binder (24507): Caught a RuntimeException from the binder stub implementation. W/Binder (24507): java.lang.StringIndexOutOfBoundsException: length=36; regionStart=1; regionLength=55 W/Binder (24507): at java.lang.StringFactory.newStringFromBytes(StringFactory.java:79) W/Binder (24507): at me.andisemler.nfc_in_flutter.NfcInFlutterPlugin.formatNDEFMessageToResult(NfcInFlutterPlugin.java:389) W/Binder (24507): at me.andisemler.nfc_in_flutter.NfcInFlutterPlugin.onTagDiscovered(NfcInFlutterPlugin.java:206) W/Binder (24507): at android.nfc.NfcActivityManager.onTagDiscovered(NfcActivityManager.java:447) W/Binder (24507): at android.nfc.IAppCallback$Stub.onTransact(IAppCallback.java:128) W/Binder (24507): at android.os.Binder.execTransactInternal(Binder.java:1021) W/Binder (24507): at android.os.Binder.execTransact(Binder.java:994)

The current content of the tag is text/plain - 03ead229-6cf3-4a2e-bc1f-b8b930f6a2b8 - this was written to the tag via a different means and I wish to overwrite it.

I should add that reading the tag has the same result.

I need to do some more debugging but perhaps onTagDiscovered shouldn't assume the tag will contain correct data. Alternatively, perform any writes first in onTagDiscovered, before attempting to parse the contents.

[semlette]

I am not able to reproduce this.

I have tried

• writing an NDEF message containing a record with type text/plain and content Test
• reading an NDEF message containing a record with type text/plain and content 03ead229-6cf3-4a2e-bc1f-b8b930f6a2b8.

Neither caused an exception during my testing.

Are you using the example app? If not, would you mind showing the Dart code that writes to the tag?

[AntSwift]

Hi, I'm not at the desk right now but to add more info, the tag was written with a different app.

The tags current content will be missing any language bit and language code which is being parsed (and failing) by the library causing the error.

I am using the example app as it is in the repo.

Ant

[semlette]

The language code should only be checked if the record has a type of T along with a TNF of WELL_KNOWN. If the record does not meet both criteria it will not check the language code or URL prefix if it was type U.

Even reading or writing a non-conforming NDEF message similar to your current one does not cause an exception on my end.