NfcSenderUtils.java

package be.digitalia.fosdem.utils;

import java.nio.charset.Charset;

import be.digitalia.fosdem.utils.NfcUtils.CreateNfcAppDataCallback;
import android.annotation.TargetApi;
import android.app.Activity;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.NfcEvent;
import android.nfc.NfcAdapter.CreateNdefMessageCallback;
import android.os.Build;

/**
 * NFC helper methods for Android Beam foreground push. This class wraps API 14+ code.
 * 
 * @author Christophe Beyls
 * 
 */
@TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH)
class NfcSenderUtils {

	public static boolean setAppDataPushMessageCallbackIfAvailable(Activity activity, final CreateNfcAppDataCallback callback) {
		NfcAdapter adapter = NfcAdapter.getDefaultAdapter(activity);
		if (adapter == null) {
			return false;
		}
		final String packageName = activity.getPackageName();
		adapter.setNdefPushMessageCallback(new CreateNdefMessageCallback() {

			@Override
			public NdefMessage createNdefMessage(NfcEvent event) {
				byte[] appData = callback.createNfcAppData();
				if (appData == null) {
					return null;
				}
				NdefRecord[] records = new NdefRecord[] { createMimeRecord("application/" + packageName, appData),
						NdefRecord.createApplicationRecord(packageName) };
				return new NdefMessage(records);
			}

		}, activity);
		return true;
	}

	static NdefRecord createMimeRecord(String mimeType, byte[] payload) {
		byte[] mimeBytes = mimeType.getBytes(Charset.forName("US-ASCII"));
		return new NdefRecord(NdefRecord.TNF_MIME_MEDIA, mimeBytes, new byte[0], payload);
	}
}