Categories: Code Examples | Java | NFC

This page was last modified 13:20, 3 January 2008.

From Forum Nokia Wiki

Example of registering and launching midlet using NFC push registry and getting event of the tag that launched the midlet. Note that push registration can also be done in jad file.

package com.nokia.nfc.sample.app;
 
import javax.microedition.contactless.ContactlessException;
import javax.microedition.contactless.DiscoveryManager;
import javax.microedition.contactless.ndef.NDEFMessage;
import javax.microedition.contactless.ndef.NDEFRecordListener;
import javax.microedition.contactless.ndef.NDEFRecordType;
import javax.microedition.io.PushRegistry;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
 
/*
 * Example of launching midlet using push registry
 * and getting event of the tag that launched the midlet.
 */
public class PushAndDetectExample extends MIDlet implements NDEFRecordListener {
 
    private Form form;
    private TextField pushTextField;
    private DiscoveryManager dm;
 
    protected void startApp() throws MIDletStateChangeException {
 
        // Create UI
        form = new Form("Form");
        pushTextField = new TextField("Pushregistration", "", 255,
                TextField.UNEDITABLE);
        form.append(pushTextField);
        Display.getDisplay(this).setCurrent(form);
 
        // Register target to discovery
        dm = DiscoveryManager.getInstance();
        try {
            dm.addNDEFRecordListener(this, new NDEFRecordType(
                    NDEFRecordType.EXTERNAL_RTD,
                    "urn:nfc:ext:yourcompany.com:pushdetectexample"));
        } catch (ContactlessException e) {
            // Catch ContactlessException
        }
 
        try {
            // Make list of connections that are already registered
            String[] regConns = PushRegistry.listConnections(false);
 
            // Boolean to tell if wanted TargetType is already registered
            boolean registered = false;
 
            // Go trough list to see if wanted TargetType is already registered
            for (int i = 0; i < regConns.length; i++) {
                if (regConns[i]
                        .equals("ndef:external_rtd?name=urn:nfc:ext:yourcompany.com:pushdetectexample")) {
                    registered = true;
                }
            }
            // If TargetType is not registered - register it
            if (!registered) {
                // Register this MIDlet to be launched when any tag with right
                // TargetType is touched
                PushRegistry
                        .registerConnection(
                                "ndef:external_rtd?name=urn:nfc:ext:yourcompany.com:pushdetectexample",
                                "com.nokia.nfc.sample.app.PushAndDetectExample", "*");
                pushTextField.setString("Succeeded");
            } else {
                // If target was alredy regisered write that on screen
                pushTextField.setString("Connection already registered");
            }
        } catch (Exception e) {
            // In case of exception write message on screen
            pushTextField.setString("Exception: " + e.getMessage());
        }
    }
 
    protected void pauseApp() {
        // TODO Auto-generated method stub
    }
 
    protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
        // TODO Auto-generated method stub
    }
 
    public void recordDetected(NDEFMessage ndefMessage) {
        // Write notification on the form when NDEF message is detected
        form.append("Record detected\n");
    }
}