NFC技术：读写NFC标签中的文本数据

//向NFC读写数据
public class ReadWriteTextMainActivity extends Activity {
    private TextView mInputText;
    private String mText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_main);

        mInputText = (TextView) findViewById(R.id.textView_inputtext);

    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        // TODO Auto-generated method stub
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1 && resultCode == 1) {
            mText = data.getStringExtra("text");
            mInputText.setText(mText);
        }

    }

    @Override
    protected void onNewIntent(Intent intent) {
        // TODO Auto-generated method stub
        super.onNewIntent(intent);
        // 读NFC文本
        if (mText == null) {
            Intent myIntent = new Intent(this, ShowNFCContentActivity.class);
            myIntent.putExtras(intent);
            myIntent.setAction(NfcAdapter.ACTION_NDEF_DISCOVERED);
            startActivity(myIntent);
        } else {
            // 写入NFC标签
            Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
            NdefMessage ndefMessage = new NdefMessage(
                    new NdefRecord[] { creatTextRecord(mText) });
            writeTag(ndefMessage, tag);

        }
    }

    public NdefRecord creatTextRecord(String text) {

        byte[] langBytes = Locale.CHINA.getLanguage().getBytes(
                Charset.forName("US-ASCII"));
        Charset utfEncoding = Charset.forName("UTF-8");
        byte[] textBytes = text.getBytes(utfEncoding);
        int utfBit = 0;
        char status = (char) (utfBit + langBytes.length);
        byte[] data = new byte[1 + langBytes.length + textBytes.length];
        data[0] = (byte) status;
        System.arraycopy(langBytes, 0, data, 1, langBytes.length);
        System.arraycopy(textBytes, 0, data, 1 + langBytes.length,
                textBytes.length);

        NdefRecord ndefRecord = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
                NdefRecord.RTD_TEXT, new byte[0], data);
        return ndefRecord;

    }

    boolean writeTag(NdefMessage ndefMessage, Tag tag) {
        try {
            Ndef ndef = Ndef.get(tag);
            ndef.connect();
            ndef.writeNdefMessage(ndefMessage);
            return true;

        } catch (Exception e) {
            // TODO: handle exception
        }

        return false;

    }
}

//读取nfc标签
public class ShowNFCContentActivity extends Activity {
    private TextView mTagContent;
    private Tag mDetecTag;
    private String mTagText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.show_nfc_tagcontent);
        mTagContent = (TextView) findViewById(R.id.textView_tag_content);
        mDetecTag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
        Ndef ndef = Ndef.get(mDetecTag);

        mTagText = ndef.getType() + "
 maxsize:" + ndef.getMaxSize()
                + "bytes 
";

        readNFCtag();

        mTagContent.setText(mTagText);

    }

    private void readNFCtag() {
        // TODO Auto-generated method stub
        if (NfcAdapter.ACTION_NDEF_DISCOVERED.equals(getIntent().getAction())) {

            Parcelable[] rawMsg = getIntent().getParcelableArrayExtra(
                    NfcAdapter.EXTRA_NDEF_MESSAGES);
            NdefMessage message[] = null;
            int contenSize = 0;
            if (rawMsg != null) {
                message = new NdefMessage[rawMsg.length];
                for (int i = 0; i < rawMsg.length; i++) {
                    message[i] = (NdefMessage) rawMsg[i];
                    contenSize += message[i].toByteArray().length;

                }
            }
            try {
                if (message != null) {
                    NdefRecord record = message[0].getRecords()[0];
                    TextRecord textRecord = TextRecord.parse(record);
                    mTagText += textRecord.getText() + "

text
"
                            + contenSize + "bytes";

                }
            } catch (Exception e) {
                // TODO: handle exception
            }
        }
    }

}

public class InputTextActivity extends Activity {
    private EditText mTextTag;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.input);
        mTextTag = (EditText) findViewById(R.id.editText1);

    }

    public void click(View view) {
        Intent intent = new Intent();
        intent.putExtra("text", mTextTag.getText().toString());
        setResult(1, intent);
        finish();
    }
}

public class TextRecord {
    private final String mText;

    private TextRecord(String text) {
        // TODO Auto-generated constructor stub

        mText = text;
    }

    public String getText() {
        return mText;
    }

    public static TextRecord parse(NdefRecord ndefRecord) {
        //
        if (ndefRecord.getTnf() != NdefRecord.TNF_WELL_KNOWN) {
            return null;
        }

        if (!Arrays.equals(ndefRecord.getType(), NdefRecord.RTD_TEXT)) {
            return null;
        }

        try {

            byte[] palyload = ndefRecord.getPayload();
            // 根据最高位判断字符编码
            String textEncoding = ((palyload[0] & 0x80) == 0) ? "UTF-8"
                    : "UTF-16";
            // 根据第六位获得语言编码长度
            int languageCodeLength = palyload[0] & 0x3f;
            // 获得语言编码
            String languageCod = new String(palyload, 1, languageCodeLength,
                    "US-ASCII");

            String text = new String(palyload, languageCodeLength + 1,
                    palyload.length - languageCodeLength - 1, textEncoding);

            return new TextRecord(text);

        } catch (Exception e) {
            // TODO: handle exception
            throw new IllegalArgumentException();
        }

    }
}