Mifare Classic 1k卡写入失败，并出现错误java.ioexception收发在Android Nexus S中失败

Question

when i am trying to write a data in Mifare classic 1k card, on Nexus S with android 2.3.3 API level 10, I am having this error. transceive failed. my code is

private View.OnClickListener write_butClickListener =new View.OnClickListener() {

    @Override
    public void onClick(View v) {


        IntentFilter ndef=new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED );
        try{
            ndef.addDataType("*/*");
        }catch(MalformedMimeTypeException e){
            throw new RuntimeException("fail",e);
        }

        mFilters=new IntentFilter[]{ndef,};
        // Setup a tech list for all NfcF tags
        mTechLists = new String[][] { new String[] { MifareClassic.class
                .getName() } };

        Intent intent=getIntent();
        String action=intent.getAction();
        if(NfcAdapter.ACTION_TECH_DISCOVERED.equals(action) ){
        String msg="Discovered Tag with Intent " + intent;
        status_Data.setText(msg);
        Tag tagFromintent=intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

        MifareClassic mfc=MifareClassic.get(tagFromintent);
        byte[] data;
        try{
            mfc.connect();
            boolean auth = false;
            String cardData = null;
            status_Data.setText("Authenticating the Tag..");

            auth = mfc.authenticateSectorWithKeyA(1,
                    MifareClassic.KEY_DEFAULT);
            if (auth){
                status_Data.setText("Authenticated");

                 String text       = "Hello, World!";
                    String lang       = "en";
                    byte[] textBytes  = text.getBytes();
                    byte[] langBytes  = lang.getBytes("US-ASCII");
                    int    langLength = langBytes.length;
                    int    textLength = textBytes.length;
                    byte[] payload    = new byte[1 + langLength + textLength];

                    // set status byte (see NDEF spec for actual bits)
                    payload[0] = (byte) langLength;

                    // copy langbytes and textbytes into payload
                    System.arraycopy(langBytes, 0, payload, 1,              langLength);
                    System.arraycopy(textBytes, 0, payload, 1 + langLength, textLength);
                    if (!mfc.isConnected()) mfc.connect();

                                    mfc.writeBlock(1, payload);
                                    mfc.close();
                showMessage("written");
            }else{
                showMessage("Authetication Failed");
                status_Data.setText("");
            }

        }
        catch(IOException e){
            status_Data.setText(e.toString());

        }



        }else{
            showMessage("Nothing to read");
        }
    }
};

any pointers

Answer 1

It seems like you're trying to directly write NDEF data onto the low-level blocks of the mifare card.

This won't work for two reasons:

1. Before you write to mifare blocks you have to authenticate yourself for write access using the authenticateSectorWithKeyA or authenticateSectorWithKeyB function. The keys for NDEF formatted mifare cards are available in the MifareClassic class.

2. You cannot directly write NDEF data onto the card and expect that other applications are able to interpret the data. NDEF is a user format. The data that gets written to the card contains extra data such as application directories, size information etc.

I suggest that you use the NDEF write functions of the generic Tag interface. These will do all the extra formatting for you.

If you want to experiment with low-level writing to the card I suggest that you first download the mifare datasheet and read what sectors and blocks are. Also it is important that you understand the authentication and security concept of the chip. Otherwise it is all to easy to accidentally overwrite the authentication blocks and destroy the tag.