android nfc P2P模式

demo下载地址http://download.csdn.net/detail/u012303938/9311167（打开手机自带的NFC 与BEAM，两个手机相碰即可传递数据）

主要代码如下：

package com.example.nfcp2p;import java.nio.charset.Charset;import java.util.Arrays;import java.util.Locale;import android.support.v7.app.ActionBarActivity;import android.app.PendingIntent;import android.content.Intent;import android.nfc.NdefMessage;import android.nfc.NdefRecord;import android.nfc.NfcAdapter;import android.nfc.NfcAdapter.CreateNdefMessageCallback;import android.nfc.NfcEvent;import android.os.Bundle;import android.os.Parcelable;import android.view.Menu;import android.view.MenuItem;import android.widget.TextView;public class MainActivity extends ActionBarActivity implements CreateNdefMessageCallback{    NfcAdapter nfcAdapter;    PendingIntent intent;    TextView tv_text;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        tv_text=(TextView) findViewById(R.id.tv_text);        nfcAdapter=NfcAdapter.getDefaultAdapter(this);        nfcAdapter.setNdefPushMessageCallback(this, this, this);        intent=PendingIntent.getActivity(this, 0, new Intent(this,getClass()), 0);    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);        return true;    }    @Override    protected void onNewIntent(Intent intent) {    // TODO Auto-generated method stub    super.onNewIntent(intent);    setIntent(intent);    if(intent.getAction().equals(NfcAdapter.ACTION_NDEF_DISCOVERED)){    Parcelable[] parcelables=intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);    String str=readRtdText(parcelables);    tv_text.setText(str);    }    }        public String readRtdText(Parcelable[] parcelables){    NdefMessage [] ndefMessages=new NdefMessage[parcelables.length];    String text="";    for(int i=0;i<parcelables.length;i++){    ndefMessages[i]=(NdefMessage) parcelables[i];            NdefRecord[]ndefRecords=ndefMessages[i].getRecords();    for(int j=0;j<ndefRecords.length;j++){    if(ndefRecords[j].getTnf()==NdefRecord.TNF_WELL_KNOWN){    if(Arrays.equals(ndefRecords[j].getType(), NdefRecord.RTD_TEXT)){    byte[] payload=ndefRecords[j].getPayload();    byte status=payload[0];    String utftype=(status&0200)==0?"UTF-8":"UTF-16";    int length=status&0077;    //RTD_TEXT由{UTF状态（0为UTF8,1<<7为UTF16）+语言编码长度}(只占一个byte)+{语言编码}+{内容}        String localdata=new String(payload, 1, length, Charset.forName("UTF-8"));        String textdata=new String(payload, 1+length, payload.length        -(1+length), Charset.forName("UTF-8"));                 text+="语言"+localdata+"内容"+textdata;    }else{    text="不是RTD_TEXT";    }    }else{    text+="不是TNF_WELL_KNOWN+"+ndefRecords[j].getTnf();    }    }    }    return text;    }    @Override    protected void onResume() {    // TODO Auto-generated method stub    super.onResume();    nfcAdapter.enableForegroundDispatch(this, intent, null, null);    }    @Override    protected void onPause() {    // TODO Auto-generated method stub    super.onPause();    nfcAdapter.disableForegroundDispatch(this);    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int id = item.getItemId();        if (id == R.id.action_settings) {            return true;        }        return super.onOptionsItemSelected(item);    }@Overridepublic NdefMessage createNdefMessage(NfcEvent event) {// TODO Auto-generated method stubNdefMessage message=getRtdText("手机号:[phone]", true, false);return message;}public NdefMessage getRtdText(String text,boolean utfEncode,boolean AAR){Locale locale=new Locale("en", "US-ASCII");byte []localedatas=locale.getLanguage().getBytes(Charset.forName("UTF-8"));Charset charset=utfEncode?Charset.forName("UTF-8"):Charset.forName("UTF-16");int utfbit=utfEncode?0:1<<7;char stauschar=(char)(utfbit+localedatas.length);byte [] textdatas=text.getBytes(charset);byte[] payload=new byte[1+localedatas.length+textdatas.length];payload[0]=(byte)stauschar;System.arraycopy(localedatas, 0, payload, 1, localedatas.length);System.arraycopy(textdatas, 0, payload, localedatas.length+1, payload.length-(localedatas.length+1));NdefRecord ndefRecord=new NdefRecord(NdefRecord.TNF_WELL_KNOWN,NdefRecord.RTD_TEXT, new byte[0], payload);if(AAR){NdefMessage ndefMessage=new NdefMessage(new NdefRecord[]{ndefRecord,NdefRecord.createApplicationRecord("com.example.nfcp2p")});return ndefMessage;}else{NdefMessage ndefMessage=new NdefMessage(new NdefRecord[]{ndefRecord});return ndefMessage;}}}