NFC broadcastreceiver problem

Question

I want my app to listen to nfc tags only when is activated. For this I tried to register an nfc listener as following, without any success.

IntentFilter filter          


        

Answer 1

Try to use Foreground Dispatch System.

To enable it, on the activity's onCreate method, you should prepare some stuffs:

PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
                getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);

after that, create the IntentFilters (in my example, all actions are handled using Intent Filters):

    IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
    try {
        ndef.addDataType("*/*");
    } catch (MalformedMimeTypeException e) {
        throw new RuntimeException("fail", e);
    }

    IntentFilter tech = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
    try {
        tech.addDataType("*/*");
    } catch (MalformedMimeTypeException e) {
        throw new RuntimeException("fail", e);
    }

    IntentFilter[] intentFiltersArray = new IntentFilter[] { tag, ndef, tech };

after that, you'll need a String array to contain supported technologies:

    String[][] techList = new String[][] { new String[] { NfcA.class.getName(),
            NfcB.class.getName(), NfcF.class.getName(),
            NfcV.class.getName(), IsoDep.class.getName(),
            MifareClassic.class.getName(),
            MifareUltralight.class.getName(), Ndef.class.getName() } };

in the onResume method, you should enable the foreground dispatch method:

NfcAdapter nfcAdapter = NfcAdapter.getDefaultAdapter(this);
nfcAdapter.enableForegroundDispatch(this, pendingIntent, intentFiltersArray, techList);

and disable in onPause:

@Override
protected void onPause() {
    super.onPause();
    nfcAdapter.disableForegroundDispatch(this);
}

By this way, you have successfully initialized the needed mechanism. To handle a received Intent you should override the onNewIntent(Intent intent) method.

@Override
public void onNewIntent(Intent intent) {
    String action = intent.getAction();

    if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
        // reag TagTechnology object...
    } else if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)) {
        // read NDEF message...
    } else if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(action)) {

    }
}

Note: if you want to handle the intents by only foreground dispatching, do not enable Intent Dispatch System in your manifest file, just give the right permissions to your application there.

I hope that helps.