Writing NFC tags

We can use NFC tags for many things, such as storing tiny amounts of data, typically ranging from a few bytes to a few megabytes, or using it to interact with other devices.

How to do it...

If we want to write to a tag, we need to obtain the tag and create a message to write:

1. In order to write to a Tag instance, we need to start listening for NFC tags:

   var adapter = NfcAdapter.GetDefaultAdapter(this);
   if (adapter != null && adapter.IsEnabled) {
     var tagDetected = new IntentFilter(
       NfcAdapter.ActionTagDiscovered);
     var pendingIntent = PendingIntent.GetActivity(
       this, 0, new Intent(this, GetType()), 0);
     adapter.EnableForegroundDispatch(
       this, pendingIntent, new[]{ tagDetected }, null);
   }

2. Once the listener has started, we can wait for the tag to be discovered and passed to the OnNewIntent() method:

   protected override void OnNewIntent(Intent intent) {
     var tag = intent.GetParcelableExtra(
       NfcAdapter.ExtraTag) as Tag;
   }

3. Once we have obtained the Tag instance...