android - 如何通过nfc将简单的字符串从android发送到android？

Question

我想通过 NFC 从一个 android 设备向另一个设备发送一个简单的字符串（文本/纯文本）。我能够以简单的字符串格式发送消息，并读取 NXP 和其他提供商已经制作的一些应用程序。我在 NDEFMessage 中发送字符串。

public class MainActivity extends Activity 
{
    private NfcAdapter mAdapter;
    private PendingIntent mPendingIntent;
    private IntentFilter[] mFilters;
    private String[][] mTechLists;
    private TextView mText,txtRead;
    private int mCount = 0;
    Tag detectedTag;
    ReadWrite rd;

    @Override
    public void onCreate(Bundle savedState) {
    super.onCreate(savedState);

    setContentView(R.layout.activity_main);
    mText = (TextView) findViewById(R.id.text);
    txtRead = (TextView) findViewById(R.id.txtRead);
    mText.setText("Scan a tag");

    rd=new ReadWrite();
    mAdapter = NfcAdapter.getDefaultAdapter(this);
    detectedTag =getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);

    // Create a generic PendingIntent that will be deliver to this activity. The NFC stack
    // will fill in the intent with the details of the discovered tag before delivering to
    // this activity.

    mPendingIntent = PendingIntent.getActivity(this, 0,
            new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);

    // Setup an intent filter for all MIME based dispatches
    IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
    try {
        ndef.addDataType("text/plain");

    } 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(),
            MifareUltralight.class.getName(),Ndef.class.getName()} };

    //onNewIntent(getIntent());

}

@Override
public void onResume() {
    super.onResume();
    if (mAdapter != null) mAdapter.enableForegroundDispatch(this, mPendingIntent, mFilters,
            mTechLists);

}

@Override
public void onNewIntent(Intent intent) {
    txtRead.setText("in on NewIntent");

    if(getIntent().getAction().equalsIgnoreCase(NfcAdapter.ACTION_NDEF_DISCOVERED) || 
            getIntent().getAction().equalsIgnoreCase(NfcAdapter.ACTION_TAG_DISCOVERED)){
        txtRead.setText("inside if  condition in on NewIntent");

        detectedTag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

        //String str=rd.readTag(detectedTag);
        //txtRead.setText(str);

        readFromTag(getIntent());
    }

    Log.i("Foreground dispatch", "Discovered tag with intent: " + intent);
    mText.setText("Discovered tag " + ++mCount + " with intent: " + intent);
}

@Override
public void onPause() {
    super.onPause();
    if (mAdapter != null) mAdapter.disableForegroundDispatch(this);
}



public void readFromTag(Intent intent){
    txtRead.setText("-1-1-1-1");

    Ndef ndef = Ndef.get(detectedTag);  

    if(ndef==null){

        txtRead.setText("ndef is null");
    }

    try{
        txtRead.setText("0000"+"\\n");
        ndef.connect();
        txtRead.setText("11111");
        Parcelable[] messages = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);
        txtRead.setText("2222");
        if (messages != null) {
            txtRead.setText("3333");
            NdefMessage[] ndefMessages = new NdefMessage[messages.length];
            txtRead.setText("4444444");
            for (int i = 0; i < messages.length; i++) {
                ndefMessages[i] = (NdefMessage) messages[i];
            }
            txtRead.setText("555555");
            NdefRecord record = ndefMessages[0].getRecords()[0];
            txtRead.setText("6666666");
            byte[] payload = record.getPayload();
            txtRead.setText("777777");

            String text = new String(payload);
            txtRead.setText("888888");
            txtRead.setText("");

            txtRead.setText(text);
            ndef.close();

        }
    }
    catch (Exception e) {
        //txtRead.setText(e.getMessage());
        Toast.makeText(getApplicationContext(), e.getMessage(), Toast.LENGTH_LONG).show();
    }

}

}