title: Reading multiple NFC tags simultaneously in Android
body: <p>The new 2.3.3 SDK includes improved NFC support, and I'd like to write an app that relies on this. Ultimately, I'd like to be able to read data from multiple tags that enter the field simultaneously, but Android only seems to trigger on the first one that enters the field - subsequent ones are ignored.</p>
  
  <p>From reading the NFC spec (ISO/IEC 14443-3) for the tags I'm using (Mifare Classic), I should be able to send a 'halt' command to the tag, which will cause it to stop responding, and allow me to read the next tag in the field. Android doesn't support the halt command directly on any of the <code>TagTechnology</code> subclasses, so I tried sending it myself directly using <code>transceive(new byte[] {0x50, 0x00})</code>. This throws an <code>IOException</code>, with the message 'transceive failed'.</p>
  
  <p>Admittedly I'm doing all this from the main thread, which I understand is a bad idea, but I just want to test the concept as easily as possible.</p>
  
  <p>Is it possible to communicate with multiple tags in the field at the same time? What am I doing wrong?</p>