Xiaomi Mobile with Android 12, and trying to use NFC-Tags to automate certain things when putting the phone near the tag, in the usual way.
Although I am using K-9 as a mail client, and have set K-9 in the system settings as the preferred mail app, the android nfc service offers the gmail app only to send mail, if a mailto-URL is set as one of the commands on an NFC tag.
Now I am trying to figure out whether Android’s NFC-service ignores the preferred app setting, or whether responding to mailto:-URLs requires a special setting, which is not set by K-9.
There is definitely a problem with K-9 and the registration of URLs. Although I can – sometimes – open K-9 from the browser when opening an url with a mailto: URL, K-9 does not get listed by Android’s RFID reader, while other apps like gmail, BlueMail, Aqua Mail (even if not configured at all and never used) are: