NfcUtils.java

package br.gov.serpro.nfc.util;

import java.io.IOException;

import android.content.Intent;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.Ndef;
import android.nfc.tech.NdefFormatable;
import android.os.Parcelable;

final public class NfcUtils {

	public static NdefMessage getAsNdef(String msg) {
		byte[] textBytes = msg.getBytes();
		NdefRecord textRecord = new NdefRecord(NdefRecord.TNF_MIME_MEDIA, "application/vnd.serpro.nfcevents".getBytes(), new byte[] {}, textBytes);
		return new NdefMessage(new NdefRecord[] { textRecord });
	}

	public static boolean writeTag(NdefMessage message, Tag tag) {
		int size = message.toByteArray().length;
		try {
			Ndef ndef = Ndef.get(tag);
			if (ndef != null) {
				ndef.connect();
				if (!ndef.isWritable()) {
					return false;
				}
				if (ndef.getMaxSize() < size) {
					return false;
				}
				ndef.writeNdefMessage(message);
				return true;
			} else {
				NdefFormatable format = NdefFormatable.get(tag);
				if (format != null) {
					try {
						format.connect();
						format.format(message);
						return true;
					} catch (IOException e) {
						return false;
					}
				} else {
					return false;
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
			return false;
		}
	}

	public static NdefMessage[] getNdefMessages(Intent intent) {
		NdefMessage[] msgs = null;
		String action = intent.getAction();
		if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action) || NfcAdapter.ACTION_NDEF_DISCOVERED.equals(action)) {
			Parcelable[] rawMsgs = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
			if (rawMsgs != null) {
				msgs = new NdefMessage[rawMsgs.length];
				for (int i = 0; i < rawMsgs.length; i++) {
					msgs[i] = (NdefMessage) rawMsgs[i];
				}
			} else {
				byte[] empty = new byte[] {};
				NdefRecord record = new NdefRecord(NdefRecord.TNF_UNKNOWN, empty, empty, empty);
				NdefMessage msg = new NdefMessage(new NdefRecord[] { record });
				msgs = new NdefMessage[] { msg };
			}
		}
		return msgs;
	}
}