Android NFC development practices

Beam examples provided in Android 4.0 SDK are indeed a good template for NFC development. For the NDEF message processing process that understands NFC, see the following code.

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. getdefaadapter adapter (this); // instantiate an NFC Device

If (mNfcAdapter = null ){

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

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

}

　　

MNfcAdapter. setNdefPushMessageCallback (this, this); // registers the NDEF callback message

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 );

}

}

}