read NFC Message - Android Network

Description

read NFC Message

Demo Code

//package com.java2s;

import java.io.UnsupportedEncodingException;

import java.util.Arrays;

import android.content.Intent;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.MifareUltralight;

import android.os.Parcelable;

public class Main {
    public final static String[] tagInfo = new String[] { "request",
            "ssid", "password" };

    public static String[] readMessage(Intent intent) {

        NdefMessage nMsg = readMsgFromTag(intent);

        return parseNdefMsg(nMsg);
    }/*from  w w w . j  av  a  2s.c o m*/

    private static NdefMessage readMsgFromTag(Intent intent) {

        System.out.println("reading msg from tag");
        Parcelable[] rawMsgs = intent
                .getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
        NdefMessage[] msgs;

        if (rawMsgs != null) {
            msgs = new NdefMessage[rawMsgs.length];
            for (int i = 0; i < rawMsgs.length; i++) {
                msgs[i] = (NdefMessage) rawMsgs[i];
            }

        } else {
            // Unknown tag type
            byte[] empty = new byte[0];
            byte[] id = intent.getByteArrayExtra(NfcAdapter.EXTRA_ID);
            Parcelable tag = intent
                    .getParcelableExtra(NfcAdapter.EXTRA_TAG);
            byte[] payload = dumpTagData(tag).getBytes();
            NdefRecord record = new NdefRecord(NdefRecord.TNF_UNKNOWN,
                    empty, id, payload);
            NdefMessage msg = new NdefMessage(new NdefRecord[] { record });
            msgs = new NdefMessage[] { msg };

        }

        return msgs[0];
    }

    private static String[] parseNdefMsg(NdefMessage nMsg) {

        NdefRecord[] records = nMsg.getRecords();

        String[] text = new String[tagInfo.length];

        int i = 0;

        for (final NdefRecord record : records) {
            //parse...

            if (record.getTnf() == NdefRecord.TNF_WELL_KNOWN
                    && Arrays.equals(record.getType(), NdefRecord.RTD_TEXT)) {

                try {

                    if (i >= tagInfo.length)
                        break;

                    byte[] payload = record.getPayload();

                    String textEncoding = ((payload[0] & 0200) == 0) ? "UTF-8"
                            : "UTF-16";
                    int languageCodeLength = payload[0] & 0077;
                    String languageCode = new String(payload, 1,
                            languageCodeLength, "US-ASCII");

                    text[i] = new String(payload, languageCodeLength + 1,
                            payload.length - languageCodeLength - 1,
                            textEncoding);

                    i++;

                } catch (UnsupportedEncodingException e) {
                    // should never happen unless we get a malformed tag.
                    throw new IllegalArgumentException(e);

                }

            }

        }

        return text;
    }

    private static String dumpTagData(Parcelable p) {
        StringBuilder sb = new StringBuilder();
        Tag tag = (Tag) p;
        byte[] id = tag.getId();
        sb.append("Tag ID (hex): ").append(getHex(id)).append("\n");
        sb.append("Tag ID (dec): ").append(getDec(id)).append("\n");
        sb.append("ID (reversed): ").append(getReversed(id)).append("\n");

        String prefix = "android.nfc.tech.";
        sb.append("Technologies: ");
        for (String tech : tag.getTechList()) {
            sb.append(tech.substring(prefix.length()));
            sb.append(", ");
        }
        sb.delete(sb.length() - 2, sb.length());
        for (String tech : tag.getTechList()) {
            if (tech.equals(MifareClassic.class.getName())) {
                sb.append('\n');
                MifareClassic mifareTag = MifareClassic.get(tag);
                String type = "Unknown";
                switch (mifareTag.getType()) {
                case MifareClassic.TYPE_CLASSIC:
                    type = "Classic";
                    break;
                case MifareClassic.TYPE_PLUS:
                    type = "Plus";
                    break;
                case MifareClassic.TYPE_PRO:
                    type = "Pro";
                    break;
                }
                sb.append("Mifare Classic type: ");
                sb.append(type);
                sb.append('\n');

                sb.append("Mifare size: ");
                sb.append(mifareTag.getSize() + " bytes");
                sb.append('\n');

                sb.append("Mifare sectors: ");
                sb.append(mifareTag.getSectorCount());
                sb.append('\n');

                sb.append("Mifare blocks: ");
                sb.append(mifareTag.getBlockCount());
            }

            if (tech.equals(MifareUltralight.class.getName())) {
                sb.append('\n');
                MifareUltralight mifareUlTag = MifareUltralight.get(tag);
                String type = "Unknown";
                switch (mifareUlTag.getType()) {
                case MifareUltralight.TYPE_ULTRALIGHT:
                    type = "Ultralight";
                    break;
                case MifareUltralight.TYPE_ULTRALIGHT_C:
                    type = "Ultralight C";
                    break;
                }
                sb.append("Mifare Ultralight type: ");
                sb.append(type);
            }
        }

        return sb.toString();
    }

    private static String getHex(byte[] bytes) {
        StringBuilder sb = new StringBuilder();
        for (int i = bytes.length - 1; i >= 0; --i) {
            int b = bytes[i] & 0xff;
            if (b < 0x10)
                sb.append('0');
            sb.append(Integer.toHexString(b));
            if (i > 0) {
                sb.append(" ");
            }
        }
        return sb.toString();
    }

    private static long getDec(byte[] bytes) {
        long result = 0;
        long factor = 1;
        for (int i = 0; i < bytes.length; ++i) {
            long value = bytes[i] & 0xffl;
            result += value * factor;
            factor *= 256l;
        }
        return result;
    }

    private static long getReversed(byte[] bytes) {
        long result = 0;
        long factor = 1;
        for (int i = bytes.length - 1; i >= 0; --i) {
            long value = bytes[i] & 0xffl;
            result += value * factor;
            factor *= 256l;
        }
        return result;
    }
}

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