OnNewIntent

I am learning how to use Xamarin with NFC. In the sample I have (https://github.com/xamarin/monodroid-samples/tree/master/NfcSample) it works fine. However, this is a single activity app. My application is a multiple activity app. Also, the same sets the EnableForegroundDispatch on the press of a button. I set it during onResume.

OnNewIntent never gets called. I am new to Xamarin and Android, so this is above my head. I've read some things about SingleTop, but I can't wrap my head around it. Does it have something to do with the activity being reused? If so, how do I fix it? Any help is greatly appreciated. Here is the code:

protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.NFC);

            // Get a reference to the default NFC adapter for this device. This adapter is how an Android application will interact with the actual hardware.
            _nfcAdapter = NfcAdapter.GetDefaultAdapter(this);
        }

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

                if (tag == null)
                {
                    return;
                }

                // This object is used to get information about the NFC tag as well as perform operations on it.
                var ndef = Ndef.Get(tag); 
                if (ndef != null) {
                    ndef.Connect ();

                    //Read Tag - convert from byte array to string
                    NdefRecord[] recs = ndef.NdefMessage.GetRecords ();
                    //byte[] type = recs[0].GetType();
                    byte[] value = recs [0].GetPayload ();
                    var str = System.Text.Encoding.Default.GetString (value);
                    Log.Debug ("Tag Value", str);
                    Toast.MakeText (this, str, ToastLength.Short).Show ();
                    this.Finish();
                }
            }
        }

protected override void OnResume()
        {
            base.OnResume ();
            EnableWriteMode();
        }

        protected override void OnPause()
        {
            base.OnPause();
            // App is paused, so no need to keep an eye out for NFC tags.
            if (_nfcAdapter != null)
                _nfcAdapter.DisableForegroundDispatch(this);
        }



        /// <summary>
        /// Identify to Android that this activity wants to be notified when 
        /// an NFC tag is discovered. 
        /// </summary>
        private void EnableWriteMode()
        {
            _inWriteMode = true;

            // Create an intent filter for when an NFC tag is discovered.  When
            // the NFC tag is discovered, Android will u
            var tagDetected = new IntentFilter(NfcAdapter.ActionTagDiscovered);
            var filters = new[] { tagDetected };

            // When an NFC tag is detected, Android will use the PendingIntent to come back to this activity.
            // The OnNewIntent method will invoked by Android.
            var intent = new Intent(this, GetType()).AddFlags(ActivityFlags.SingleTop);
            var pendingIntent = PendingIntent.GetActivity(this, 0, intent, 0);

            if (_nfcAdapter == null) {
                var alert = new AlertDialog.Builder (this).Create ();
                alert.SetMessage ("NFC is not supported on this device.");
                alert.SetTitle ("NFC Unavailable");
                alert.SetButton ("OK", delegate {
                    //_writeTagButton.Enabled = false;
                    //_textView.Text = "NFC is not supported on this device.";
                });
                alert.Show ();
            } else
                _nfcAdapter.EnableForegroundDispatch(this, pendingIntent, filters, null);
        }