在android上的nfc标签中写文本的问题

Question

我试图通过android在NTAG213芯片上写NFC标签，使用的终端是nexus 7，它给我的错误是：

  

11-29 13：45：14.651：E / NFC（5184）：NFC服务死亡11-29 13：45：14.651：E / NFC（5184）：android.os.DeadObjectException 11-29 13:45： 14.651：E / NFC（5184）：在android.os.BinderProxy.transactNative（Native Method）11-29 13：45：14.651：E / NFC（5184）：在android.os.BinderProxy.transact（Binder.java： 496）11-29 13：45：14.651：E / NFC（5184）：在android.nfc.INfcTag $ Stub $ Proxy.formatNdef（INfcTag.java:513)11-29 13：45：14.651：E / NFC（ 5184）：在android.nfc.tech.NdefFormatable.format（NdefFormatable.java:126)11-29 13：45：14.651：E / NFC（5184）：at android.nfc.tech.NdefFormatable.format（NdefFormatable.java ：94）11-29 13：45：14.651：E / NFC（5184）：at com.framentos.hellonfc.MainActivity.write（MainActivity.java:106）

我的java代码是：

    public class MainActivity extends Activity{

NfcAdapter adapter;
PendingIntent pendingIntent;
IntentFilter writeTagFilters[];
boolean writeMode;
Tag mytag;
Context ctx;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ctx=this;
    Button btnWrite = (Button) findViewById(R.id.button);
    final TextView message = (TextView)findViewById(R.id.edit_message);

    btnWrite.setOnClickListener(new View.OnClickListener()
    {
        @Override
        public void onClick(View v) {
            try {
                if(mytag==null){
                    Toast.makeText(ctx, ctx.getString(R.string.error_detected), Toast.LENGTH_LONG ).show();
                }else{
                    write(message.getText().toString(),mytag);
                    Toast.makeText(ctx, ctx.getString(R.string.ok_writing), Toast.LENGTH_LONG ).show();
                }
            } catch (IOException e) {
                Toast.makeText(ctx, ctx.getString(R.string.error_writing), Toast.LENGTH_LONG ).show();
                e.printStackTrace();
            } catch (FormatException e) {
                Toast.makeText(ctx, ctx.getString(R.string.error_writing) , Toast.LENGTH_LONG ).show();
                e.printStackTrace();
            }
        }
    });

    adapter = NfcAdapter.getDefaultAdapter(this);
    pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
    IntentFilter tagDetected = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
    tagDetected.addCategory(Intent.CATEGORY_DEFAULT);
    writeTagFilters = new IntentFilter[] { tagDetected };

}



private void write(String text, Tag tag) throws IOException, FormatException {

    NdefRecord[] records = { createRecord(text) };
    NdefMessage  message = new NdefMessage(records);
    // Get an instance of Ndef for the tag.
     int size = message.toByteArray().length;
    Ndef ndef = Ndef.get(tag);
    if (ndef != null)
    {
         ndef.connect();
         if (ndef.isWritable() && ndef.getMaxSize() > size)
     {
         ndef.writeNdefMessage(message);
         //Miscellaneous.logEvent("i", "NFC", "Done writing tag.", 2);
         //return true;

     }
         ndef.close();
 }
 else
 {
     NdefFormatable format = NdefFormatable.get(tag);
     if (format != null)
     {
         try
         {
             format.connect();
             format.format(message);
             format.close();
             //Miscellaneous.logEvent("i", "NFC", "Done writing tag.", 2);
             //return true;
         }
         catch(IOException e)
         {
             //Miscellaneous.logEvent("e", "NFC", "Error writing tag: " + Log.getStackTraceString(e), 2);
         }
     }
 }


}



private NdefRecord createRecord(String text) throws UnsupportedEncodingException {
    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);

    NdefRecord recordNFC = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,  NdefRecord.RTD_TEXT,  new byte[0], payload);

    return recordNFC;
}


@Override
protected void onNewIntent(Intent intent){
    if(NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())){
        mytag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);    
        Toast.makeText(this, this.getString(R.string.ok_detection) + mytag.toString(), Toast.LENGTH_LONG ).show();
    }
}

@Override
public void onPause(){
    super.onPause();
    WriteModeOff();
}

@Override
public void onResume(){
    super.onResume();
    WriteModeOn();
}

private void WriteModeOn(){
    writeMode = true;
    adapter.enableForegroundDispatch(this, pendingIntent, writeTagFilters, null);
}

private void WriteModeOff(){
    writeMode = false;
    adapter.disableForegroundDispatch(this);
}

}

和我androidmanifest.xml是：

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.framentos.hellonfc"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="14" />

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name="com.framentos.hellonfc.MainActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                    <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>
            <intent-filter>
                <action android:name="android.nfc.action.NDEF_DISCOVERED"/>
                <category android:name="android.intent.category.DEFAULT"/>
                <data android:mimeType="text/plain"/>
        </intent-filter>
        </activity>

    </application>
    <uses-permission android:name="android.permission.NFC" />

</manifest>

有人能帮助我吗？谢谢。