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Simple example MIDlet that can write image to RFID tag and read it from it. Writing is done using TargetListener and NDEFTagConnection. Reading using NDEFRecordListener. Image ised in this example: Media:smiley.png

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
 
import javax.microedition.contactless.ContactlessException;
import javax.microedition.contactless.DiscoveryManager;
import javax.microedition.contactless.TargetListener;
import javax.microedition.contactless.TargetProperties;
import javax.microedition.contactless.TargetType;
import javax.microedition.contactless.ndef.NDEFMessage;
import javax.microedition.contactless.ndef.NDEFRecord;
import javax.microedition.contactless.ndef.NDEFRecordListener;
import javax.microedition.contactless.ndef.NDEFRecordType;
import javax.microedition.contactless.ndef.NDEFTagConnection;
import javax.microedition.io.Connector;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Image;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
 
/*
 * Simple example that can write image to RFID tag and read it from it.
 * Writing is done using TargetListener and NDEFTagConnection.
 * Reading using NDEFRecordListener.
 */
public class ImageWrite extends MIDlet implements TargetListener,
        NDEFRecordListener, CommandListener {
 
    private DiscoveryManager dm;
 
    private Form form;
 
    // Read and write commands to set mode of the application
    private Command readCommand;
 
    private Command writeCommand;
 
    // Boolean telling in which mode the application is
    private boolean read = true;
 
    protected void startApp() throws MIDletStateChangeException {
        dm = DiscoveryManager.getInstance();
 
        try {
            // Register NDEF tag to target listener..
            dm.addTargetListener(this, TargetType.NDEF_TAG);
            // ..and png image mime type to NDEF record listener.
            dm.addNDEFRecordListener(this, new NDEFRecordType(
                    NDEFRecordType.MIME, "image/png"));
        } catch (IllegalStateException e) {
            form.append(e.toString());
        } catch (ContactlessException e) {
            form.append(e.toString());
        }
        form = new Form("Form");
        readCommand = new Command("Read", Command.OK, 1);
        writeCommand = new Command("Write", Command.OK, 1);
        form.addCommand(writeCommand);
        form.setCommandListener(this);
        Display.getDisplay(this).setCurrent(form);
    }
 
    protected void pauseApp() {
    }
 
    protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
    }
 
    // NDEF tag detected
    public void targetDetected(TargetProperties[] properties) {
        // If application is not in read mode - write image to tag
        if (!read) {
            NDEFTagConnection conn = null;
            try {
                // Open connection to NDEF tag
                conn = (NDEFTagConnection) Connector.open(properties[0]
                        .getUrl());
 
                // Read image from phone to ByteArrayOutputStream
                InputStream is = getClass().getResourceAsStream("smiley.png");
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                int c;
                while ((c = is.read()) != -1) {
                    baos.write(c);
                }
 
                // Create NDEF Record to be added to NDEF Message
                NDEFRecord recordToWrite = new NDEFRecord(new NDEFRecordType(
                        NDEFRecordType.MIME, "image/png"), null, baos
                        .toByteArray());
 
                // Create NDEF Message and add created record in it.
                NDEFMessage write_container = new NDEFMessage();
                write_container.appendRecord(recordToWrite);
 
                // Write NDEF Message to tag
                conn.writeNDEF(write_container);
 
                form.append("Image witten");
 
            } catch (IOException e) {
                form.append(e.toString());
            } catch (Exception e) {
                form.append(e.toString());
            } finally {
                try {
                    if (conn != null) {
                        conn.close();
                    }
                } catch (IOException e) {
                    form.append(e.toString());
                }
            }
        }
    }
 
    // proper NDEF message detected
    public void recordDetected(NDEFMessage mes) {
        // If application is in read mode - show image from tag
        if (read) {
            // Get png image record from NDEF message
            NDEFRecord rec[] = mes.getRecord(new NDEFRecordType(
                    NDEFRecordType.MIME, "image/png"));
 
            // Create Image from payload data from record - which is the image
            // as byte array.
            Image img = Image.createImage(rec[0].getPayload(), 0, (int) rec[0]
                    .getPayloadLength());
            form.append(img);
        }
    }
 
    // Change application mode from reading to writing and vice versa
    public void commandAction(Command c, Displayable d) {
        if (read) {
            read = false;
            form.removeCommand(writeCommand);
            form.addCommand(readCommand);
        } else {
            read = true;
            form.removeCommand(readCommand);
            form.addCommand(writeCommand);
        }
    }
}