MifareClassic format read/write in android nfc

Data formats supported by Android

Intent filter in Data Format

In the AndroidManifest. xml file Specify the resource file you created in the element:

<喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> VcD4KPHByZSBjbGFzcz0 = "brush: java;">... ...

Nfc_tech_filter.xml file (a Tag is considered to be matched only when all Tags match the nfc chip specified by the tech element in the tech-list element ):

 
  
   
    android.nfc.tech.IsoDep
   
   
    android.nfc.tech.NfcA
   
   
    android.nfc.tech.NfcB
   
   
    android.nfc.tech.NfcF
   
   
    android.nfc.tech.NfcV
   
   
    android.nfc.tech.Ndef
   
   
    android.nfc.tech.NdefFormatable
   
   
    android.nfc.tech.MifareClassic
   
   
    android.nfc.tech.MifareUltralight
   
  
 

You can also create multiple resource files (multiple resource files are in the OR relationship, AND the chips in each resource file are in the AND relationship ):

 
  
   
    android.nfc.tech.NfcA
   
   
    android.nfc.tech.Ndef
   
   
    android.nfc.tech.NdefFormatable
   
  
 

 
  
   
    android.nfc.tech.Ndef
   
   
    android.nfc.tech.NdefFormatable
   
  
 

Or create multiple Element (multiple The relationship between elements is OR, Element Is the AND relationship ):

     
      
       
        android.nfc.tech.NfcA
       
      
      
       
        android.nfc.tech.NfcB
       
      
      
       
        android.nfc.tech.MifareClassic
       
      
     

You can view the data format supported by tags:

Use the Tag. getTechlist () method to obtain the data format supported by the Tag.

Obtain the unique ID of a Tag using the Tag. getId () method.

NfcAdapter = null: indicates that the device does not support NFC hardware.

NfcAdapter. isEnable () method: Determine whether NFC is enabled

To sum up:

A Tag obtains all the Tag types supported by the Tag. getTechlist () method. All resources The chips in are Tag tags. All the subsets that support tags are matched. You can write multiple , Each Is independent, as long as one of All All the chip types in the matching Tag support the chip is considered to be matched. Multiple Yes OR relationship, In Is the AND relationship.

Shape Structure of MifareClassic labels

Data Structure of MifareClassic labels

Note (assuming 1 K space ):

The first sector is generally used by the manufacturer to occupy blocks.

0-15 sectors: One slice corresponds to four blocks, so there are 64 blocks in total, with numbers 0-63 respectively. The first slice corresponds to 0-3 blocks, and the second slice corresponds: 4-7 blocks...

The last block of each slice is used to store the password or control bit. The rest is the data block. One block occupies 16 bytes. keyA occupies 6 bytes, the control bit occupies 4 bytes, and keyB occupies 6 bytes.

Common Methods for MifareClassic

Get (): gets the MifareClassic object based on the Tag object;

Connect (): allows I/O operations on MifareClassic labels;

GetType (): Obtain the specific type of the MifareClassic Tag: TYPE_CLASSIC, TYPE_PLUA, TYPE_PRO, TYPE_UNKNOWN;

GetSectorCount (): obtains the total number of slices of a tag;

GetBlockCount (): obtains the total number of blocks of a tag;

GetSize (): Obtain the tag capacity: SIZE_1K, SIZE_2K, SIZE_4K, SIZE_MINI

AuthenticateSectorWithKeyA (int SectorIndex, byte [] Key): Verify the KeyA password of the current sector. The return value is true or false.

Commonly used KeyA: default factory password: KEY_DEFAULT,

Suppliers of various purposes must cooperate with the MAD: KEY_MIFARE_APPLICATION_DIRECTORY of the technology.

Password formatted as NDEF: KEY_NFC_FORUM

GetBlockCountInSector (int): obtains the number of blocks contained in the current sector;

SectorToBlock (int): The block number of the first block of the current sector;

WriteBlock (int, data): writes data to the current block;

ReadBlock (int): Read the data of the current block.

Close (): IO operations on tags are prohibited to release resources.

Read/write process of MifareClassic labels

Get the Adapter object

Get Tag object

Obtain the MifareClassic object

Read data from data blocks

Connect (), readBlock (), close ()

Get the Adapter object

Get Tag object

Obtain the MifareClassic object

Write Data blocks to tags

Connect (), writeBlock (), close ()

Official documentation:

Working with tag technologies and the ACTION_TECH_DISCOVERED intent

When a device scans a tag that has NDEF data on it, but cocould not be mapped to a MIME or URI, the tag dispatch system tries to start an activity withACTION_TECH_DISCOVEREDIntent.ACTION_TECH_DISCOVEREDIs also used when a tag with non-NDEF data is scanned. having this fallback allows you to work with the data on the tag directly if the tag dispatch system cocould not parse it for you. the basic steps when working with tag technologies are as follows:

1. Filter forACTION_TECH_DISCOVEREDIntent specifying the tag technologies that you want to handle. SeeFiltering for NFC intents for more information. In general, the tag dispatch system tries to startACTION_TECH_DISCOVEREDIntent when an NDEF message cannot be mapped to a MIME type or URI, or if the tag scanned did not contain NDEF data. for more information on how this is determined, see The Tag Dispatch System.
2. When your application es the intent, obtainTagObject from the intent:

   Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

3. Obtain an instance ofTagTechnology, By calling one ofgetFactory methods of the classes inandroid.nfc.techPackage. You can enumerate the supported technologies of the tag by callinggetTechList()Before callinggetFactory method. For example, to obtain an instanceMifareUltralightFromTag, Do the following:

   MifareUltralight.get(intent.getParcelableExtra(NfcAdapter.EXTRA_TAG));

   Reading and writing to tags

   Reading and writing to an NFC tag involves obtaining the tag from the intent and opening communication with the tag. you must define your own protocol stack to read and write data to the tag. keep in mind, however, that you can still read and write NDEF data when working directly with a tag. it is up to you how you want to structure things. the following example shows how to work with a MIFARE Ultralight tag.

   package com.example.android.nfc;import android.nfc.Tag;import android.nfc.tech.MifareUltralight;import android.util.Log;import java.io.IOException;import java.nio.charset.Charset;public class MifareUltralightTagTester {    private static final String TAG = MifareUltralightTagTester.class.getSimpleName();    public void writeTag(Tag tag, String tagText) {        MifareUltralight ultralight = MifareUltralight.get(tag);        try {            ultralight.connect();            ultralight.writePage(4, "abcd".getBytes(Charset.forName("US-ASCII")));            ultralight.writePage(5, "efgh".getBytes(Charset.forName("US-ASCII")));            ultralight.writePage(6, "ijkl".getBytes(Charset.forName("US-ASCII")));            ultralight.writePage(7, "mnop".getBytes(Charset.forName("US-ASCII")));        } catch (IOException e) {            Log.e(TAG, "IOException while closing MifareUltralight...", e);        } finally {            try {                ultralight.close();            } catch (IOException e) {                Log.e(TAG, "IOException while closing MifareUltralight...", e);            }        }    }    public String readTag(Tag tag) {        MifareUltralight mifare = MifareUltralight.get(tag);        try {            mifare.connect();            byte[] payload = mifare.readPages(4);            return new String(payload, Charset.forName("US-ASCII"));        } catch (IOException e) {            Log.e(TAG, "IOException while writing MifareUltralight            message...", e);        } finally {            if (mifare != null) {               try {                   mifare.close();               }               catch (IOException e) {                   Log.e(TAG, "Error closing tag...", e);               }            }        }        return null;    }}

   
   

   
   

   Example program:

   
   MainActivity:

   Package mobile. android. mifareultralight; import java. io. IOException; import java. nio. charset. charset; import android. app. activity; import android. app. pendingIntent; import android. content. intent; import android. nfc. nfcAdapter; import android. nfc. tag; import android. nfc. tech. mifareClassic; import android. OS. bundle; import android. util. log; import android. widget. checkBox; import android. widget. toast; public class MifareultralightMainActivity extends Activity {private CheckBox mWriteData; private NfcAdapter mNfcAdapter; private PendingIntent mPendingIntent; @ Override public void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_mifareultralight); mWriteData = (CheckBox) findViewById (R. id. checkbox_write); mNfcAdapter = mNfcAdapter. getdefaadapter adapter (t His); if (mNfcAdapter = null) {Toast. makeText (this, "the device does not support NFC! ", Toast. LENGTH_LONG). show (); finish (); return;} if (! MNfcAdapter. isEnabled () {Toast. makeText (this, "enable NFC in system settings first! ", Toast. LENGTH_LONG ). show (); finish (); return;} mPendingIntent = PendingIntent. getActivity (this, 0, new Intent (this, getClass (), 0) ;}@ Override public void onResume () {super. onResume (); if (mNfcAdapter! = Null) mNfcAdapter. enableForegroundDispatch (this, mPendingIntent, null, null) ;}@ Override public void onNewIntent (Intent intent) {Tag tag = intent. getParcelableExtra (mNfcAdapter. EXTRA_TAG); String [] techList = tag. getTechList (); boolean haveMifareUltralight = false; for (String tech: techList) {if (tech. indexOf ("MifareClassic")> = 0) {haveMifareUltralight = true; break ;}} if (! HaveMifareUltralight) {Toast. makeText (this, "MifareClassic not supported", Toast. LENGTH_LONG ). show (); return;} if (mWriteData. isChecked () {writeTag (tag);} else {String data = readTag (tag); if (data! = Null) {Log. I (data, "ouput"); Toast. makeText (this, data, Toast. LENGTH_LONG ). show () ;}}@ Override public void onPause () {super. onPause (); if (mNfcAdapter! = Null) mNfcAdapter. disableForegroundDispatch (this);} public void writeTag (Tag tag) {MifareClassic mfc = MifareClassic. get (tag); try {mfc. connect (); boolean auth = false; short sectorAddress = 1; auth = mfc. authenticateSectorWithKeyA (sectorAddress, MifareClassic. KEY_NFC_FORUM); if (auth) {// the last block of the sector is used for KeyA and KeyB cannot be overwritted mfc. writeBlock (4, "13138384" 38000000 ". getBytes (); mfc. writeBlock (5, "1322676888000000 ". getBytes (); mfc. close (); Toast. makeText (this, "Write successful", Toast. LENGTH_SHORT ). show () ;}} catch (IOException e) {// TODO Auto-generated catch block e. printStackTrace ();} finally {try {mfc. close ();} catch (IOException e) {// TODO Auto-generated catch block e. printStackTrace () ;}}// convert the Character Sequence to a hexadecimal String private String bytesToHexString (byte [] Src) {StringBuilder stringBuilder = new StringBuilder ("0x"); if (src = null | src. length <= 0) {return null;} char [] buffer = new char [2]; for (int I = 0; I <src. length; I ++) {buffer [0] = Character. forDigit (src [I] >>> 4) & 0x0F, 16); buffer [1] = Character. forDigit (src [I] & 0x0F, 16); System. out. println (buffer); stringBuilder. append (buffer);} return stringBuilder. toString ();} public Str Ing readTag (Tag tag) {MifareClassic mfc = MifareClassic. get (tag); for (String tech: tag. getTechList () {System. out. println (tech);} boolean auth = false; // read TAG try {String metaInfo = ""; // Enable I/O operations to the tag from this TagTechnology object. mfc. connect (); int type = mfc. getType (); // The type of the obtained TAG int sectorCount = mfc. getSectorCount (); // obtain the number of slice contained in the TAG String typeS = ""; switch (type ){ Case MifareClassic. TYPE_CLASSIC: typeS = "TYPE_CLASSIC"; break; case MifareClassic. TYPE_PLUS: typeS = "TYPE_PLUS"; break; case MifareClassic. TYPE_PRO: typeS = "TYPE_PRO"; break; case MifareClassic. TYPE_UNKNOWN: typeS = "TYPE_UNKNOWN"; break;} metaInfo + = "card type:" + typeS + "\ n total" + sectorCount + "slice \ n total" + mfc. getBlockCount () + "Block \ n storage space:" + mfc. getSize () + "B \ n"; for (int j = 0; j <sectorCount; J ++) {// Authenticate a sector with key. auth = mfc. authenticateSectorWithKeyA (j, MifareClassic. KEY_NFC_FORUM); int bCount; int bIndex; if (auth) {metaInfo + = "Sector" + j + ": Verification Successful \ n "; // read the block bCount = mfc in the slice. getBlockCountInSector (j); bIndex = mfc. sectorToBlock (j); for (int I = 0; I <bCount; I ++) {byte [] data = mfc. readBlock (bIndex); metaInfo + = "Block" + bIndex + ":" + bytesToHexString (d Ata) + "\ n"; bIndex ++ ;}} else {metaInfo + = "Sector" + j + ": Verification Failed \ n" ;}} return metaInfo ;} catch (Exception e) {Toast. makeText (this, e. getMessage (), Toast. LENGTH_LONG ). show (); e. printStackTrace ();} finally {if (mfc! = Null) {try {mfc. close ();} catch (IOException e) {Toast. makeText (this, e. getMessage (), Toast. LENGTH_LONG ). show () ;}} return null ;}}

   
   Configuration file: