Android NFC开发实战_安卓软件开发

　　对于Android 4.0 SDK中提供的Beam例子，对于NFC开发来说的确是一个不错的模板。对于了解NFC的NDEF消息处理过程不妨看下面的代码。

　　public class Beam extends Activity implements CreateNdefMessageCallback,

　　OnNdefPushCompleteCallback {

　　NfcAdapter mNfcAdapter;

　　TextView mInfoText;

　　private static final int MESSAGE_SENT = 1;

　　@Override

　　public void onCreate(Bundle savedInstanceState) {

　　super.onCreate(savedInstanceState);

　　setContentView(R.layout.main);

　　mInfoText = (TextView) findViewById(R.id.textView);

　　mNfcAdapter = NfcAdapter.getDefaultAdapter(this); //实例化NFC设备

　　if (mNfcAdapter == null) {

　　mInfoText = (TextView) findViewById(R.id.textView);

　　mInfoText.setText("NFC is not available on this device.");

　　}

　　mNfcAdapter.setNdefPushMessageCallback(this, this); //注册NDEF回调消息

　　mNfcAdapter.setOnNdefPushCompleteCallback(this, this);

　　}

　　@Override

　　public NdefMessage createNdefMessage(NfcEvent event) {

　　Time time = new Time();

　　time.setToNow();

　　String text = ("Beam me up!nn" +

　　"Beam Time: " + time.format("%H:%M:%S"));

　　NdefMessage msg = new NdefMessage(

　　new NdefRecord[] { createMimeRecord(

　　"application/com.example.android.beam", text.getBytes())

　　});

　　return msg;

　　}

　　@Override

　　public void onNdefPushComplete(NfcEvent arg0) {

　　// A handler is needed to send messages to the activity when this

　　// callback occurs, because it happens from a binder thread

　　mHandler.obtainMessage(MESSAGE_SENT).sendToTarget();

　　}

　　private final Handler mHandler = new Handler() {

　　@Override

　　public void handleMessage(Message msg) {

　　switch (msg.what) {

　　case MESSAGE_SENT:

　　Toast.makeText(getApplicationContext(), "Message sent!", Toast.LENGTH_LONG).show();

　　break;

　　}

　　}

　　};

　　@Override

　　public void onResume() {

　　super.onResume();

　　if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {

　　processIntent(getIntent());

　　}

　　}

　　@Override

　　public void onNewIntent(Intent intent) {

　　// onResume gets called after this to handle the intent

　　setIntent(intent);

　　}

　　/**

　　* Parses the NDEF Message from the intent and prints to the TextView

　　*/

　　void processIntent(Intent intent) {

　　Parcelable[] rawMsgs = intent.getParcelableArrayExtra(

　　NfcAdapter.EXTRA_NDEF_MESSAGES);

　　// only one message sent during the beam

　　NdefMessage msg = (NdefMessage) rawMsgs[0];

　　// record 0 contains the MIME type, record 1 is the AAR, if present

　　mInfoText.setText(new String(msg.getRecords()[0].getPayload()));

　　}

　　/**

　　* Creates a custom MIME type encapsulated in an NDEF record

　　*

　　* @param mimeType

　　*/

　　public NdefRecord createMimeRecord(String mimeType, byte[] payload) {

　　byte[] mimeBytes = mimeType.getBytes(Charset.forName("US-ASCII"));

　　NdefRecord mimeRecord = new NdefRecord(

　　NdefRecord.TNF_MIME_MEDIA, mimeBytes, new byte[0], payload);

　　return mimeRecord;

　　}

　　@Override

　　public boolean onCreateOptionsMenu(Menu menu) {

　　// If NFC is not available, we won't be needing this menu

　　if (mNfcAdapter == null) {

　　return super.onCreateOptionsMenu(menu);

　　}

　　MenuInflater inflater = getMenuInflater();

　　inflater.inflate(R.menu.options, menu);

　　return true;

　　}

　　@Override

　　public boolean onOptionsItemSelected(MenuItem item) {

　　switch (item.getItemId()) {

　　case R.id.menu_settings:

　　Intent intent = new Intent(Settings.ACTION_NFCSHARING_SETTINGS);

　　startActivity(intent);

　　return true;

　　default:

　　return super.onOptionsItemSelected(item);

　　}

　　}

　　}