Reading multiple NFC tags simultaneously in Android

What you want is unfortunately not possible at the moment, unless you do some pretty advanced hackery, which is almost never a good idea :)

Probably you could halt the card if you send the right bytes in the transceive(), as you're trying to do now. But since the halt (or rather, the HLTA which you're trying to send) is an ISO14443-3A command, this will not work through the MifareClassic interface - which uses an "encrypted" pipe. Directly transmitting over the NfcA interface unfortunately doesn't work with the current stack either.

Even if you could get the card to halt, this will not automatically cause the NFC chip in the phone to resume polling for new tags - since you are "going around" the stack.

Depending on my short experience you can not work with multiple tags.If two tags are in the field you do not receive an ID from the tag, it's binary zero.So my guess is that, at this point, you can only access one tag and no more than one can be in the field.

Have you had success sending other commands using transceive such as read block (0x30, 0x(block)) or authenticate sector commands? Just thinking you might want to be sure you're using transceive correctly in the first place.