由于Android具有良好的開源優(yōu)勢(shì)，可進(jìn)行深度定制開發(fā)。安卓系統(tǒng)市場(chǎng)應(yīng)用比windows晚，雖然支持的應(yīng)用不如windows系統(tǒng)多，但由于系統(tǒng)的免費(fèi)開放性，眾多軟件廠商經(jīng)過近幾年的開發(fā)，已經(jīng)有越來越多的應(yīng)用加入進(jìn)來，目前支持辦公、教學(xué)、娛樂已經(jīng)完全沒有問題。因此，越來越多的行業(yè)接受并認(rèn)可基于Android操作系統(tǒng)的設(shè)備。

目前市面上大多數(shù)工業(yè)控制設(shè)備開始采用Android系統(tǒng)了，然而這部分設(shè)備并沒有搭載原生的NFC功能。隨著近年來，NFC功能需求的興起，很多行業(yè)需要一直可以支持Android系統(tǒng)的可接入Android設(shè)備并進(jìn)行二次開發(fā)的NFC讀寫器。因此，L3-U這款NFC讀寫器 應(yīng)運(yùn)而生。作為一款采用USB免驅(qū)的NFC讀寫器，支持在windows、Android、linux等操作系統(tǒng)，免費(fèi)提供基于上述各種系統(tǒng)的SDK，方便客戶進(jìn)行功能擴(kuò)展和二次開發(fā)。

L3-U這款USB免驅(qū)動(dòng)NFC讀寫器已經(jīng)設(shè)計(jì)好了USB 驅(qū)動(dòng)，用戶在基于Android系統(tǒng)的設(shè)備上只有能獲取USB HOST權(quán)限或者采用OTG傳輸就可以使用，無需安裝額外驅(qū)動(dòng)。如果你其它非標(biāo)準(zhǔn)的Android設(shè)備，需要提供設(shè)備我們進(jìn)行編譯驅(qū)動(dòng)。以下為標(biāo)準(zhǔn)的具有USB HOST權(quán)限的設(shè)備接入NFC讀寫器的過程。供大家在進(jìn)行NFC讀寫器二次開發(fā)過程中參考！

1、在項(xiàng)目中對(duì)AndroidManifest.xml文件進(jìn)行配置，獲取相關(guān)權(quán)限。

     <uses-permission android:name="android.permission.NFC" />
    <uses-feature
        android:name="android.hardware.nfc"
        android:required="true" />    
    <uses-sdk
        android:minSdkVersion="12"
        android:targetSdkVersion="17" />
              <intent-filter>
                <action android:name="android.nfc.action.NDEF_DISCOVERED" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:mimeType="text/*" />
            </intent-filter>                       
            <intent-filter>
                <action android:name="android.nfc.action.TECH_DISCOVERED" />
            </intent-filter>
            <meta-data
                android:name="android.nfc.action.TECH_DISCOVERED"
                android:resource="@xml/nfc_tech_filter" />           

2、建立一個(gè)Activity頁(yè)面，用于實(shí)現(xiàn)NFC讀寫的功能。NFC讀寫功能實(shí)現(xiàn)的代碼如下：

package cc.lotusnfc;
import java.io.IOException;
import java.nio.charset.Charset;
import java.sql.Date;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import cc.lotusnfc.R;
import android.nfc.FormatException;
import android.nfc.NdefMessage;
import android.nfc.NdefRecord;
import android.nfc.NfcAdapter;
import android.nfc.NfcManager;
import android.nfc.Tag;
import android.nfc.tech.MifareClassic;
import android.nfc.tech.Ndef;
import android.nfc.tech.NfcA;
import android.os.Bundle;
import android.os.Parcelable;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
	private TextView resultText;
	private PendingIntent pendingIntent;
	private IntentFilter[] mFilters;
	private String[][] mTechLists;
	private Button mJumpTagBtn;
	private boolean isFirst = true;
	private NfcAdapter m_NfcAdpater;
	private EditText m_edtLog;
	private Intent m_NfcIntent  = null;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// 獲取nfc適配器，判斷設(shè)備是否支持NFC功能
		m_NfcAdpater = NfcAdapter.getDefaultAdapter(this);
		if (m_NfcAdpater == null) {
			Toast.makeText(this, "Not Found NfcAdapter!", Toast.LENGTH_SHORT)
					.show();
			//finish();
			//return;
		} else if (!m_NfcAdpater.isEnabled()) {
			Toast.makeText(this, "Please Enabled NfcAdapter",
					Toast.LENGTH_SHORT).show();
			//finish();
			//return;
		}
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		m_edtLog = (EditText) findViewById(R.id.edtLog);
		m_edtLog.setText("");
		pendingIntent = PendingIntent.getActivity(this, 0, new Intent(this,
				getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
		IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
		ndef.addCategory("*/*");
		mFilters = new IntentFilter[] { ndef };// 過濾器
		mTechLists = new String[][] {
				new String[] { MifareClassic.class.getName() },
				new String[] { NfcA.class.getName() } };// 允許掃描的標(biāo)簽類型
	}
	@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;
	}
	@SuppressLint("NewApi")
	@Override
	protected void onResume() {
		// TODO Auto-generated method stub
		super.onResume();
		m_NfcAdpater.enableForegroundDispatch(this, pendingIntent, mFilters,
				mTechLists);
	}
	private NdefMessage createMessage(String text) {
		NdefRecord[] record = new NdefRecord[1];
		String lang = "en";
		byte[] langBytes = lang.getBytes(Charset.forName("US-ASCII"));
		byte[] textBytes = text.getBytes(Charset.forName("UTF-8"));
		char status = (char) (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);
		record[0] = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
				NdefRecord.RTD_TEXT, new byte[0], data);
		return new NdefMessage(record);
	}
	@Override
	protected void onNewIntent(Intent intent) {
		// TODO Auto-generated method stub
		super.onNewIntent(intent);
		m_NfcIntent = intent;
		String strWriteText = "春眠不覺曉";
		if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(intent.getAction())) {
			Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
			Ndef ndef = Ndef.get(tagFromIntent);
			if (ndef != null) {
				NdefMessage ndefMessage = createMessage(strWriteText);
				try {
					ndef.connect();
					// READ
					NdefMessage msg = ndef.getNdefMessage();
					if(null == msg) return;
					NdefRecord[] records = msg.getRecords();
					// NdefMessage nmsg = (NdefMessage) msgs[0];
					NdefRecord record = records[0];
					String resultStr = "";
					if (record.getTnf() == NdefRecord.TNF_WELL_KNOWN) {
						if (Arrays
								.equals(record.getType(), NdefRecord.RTD_TEXT)) {
							byte[] payload = record.getPayload();
							if (payload == null)
								return;
							try {
								String textEString = ((payload[0] & 0x80) == 0) ? "UTF-8"
										: "UTF-16";
								int languageCodeLength = payload[0] & 0x3f;
								resultStr = new String(payload,
										languageCodeLength + 1, payload.length
												- languageCodeLength - 1,
										textEString);
								AddLog("Read:" + resultStr);
							} catch (Exception e) {
								e.printStackTrace();
							}
						}
					}
					// WRITE
					ndef.writeNdefMessage(ndefMessage);
					AddLog("WRITE:" + strWriteText);
					ndef.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
					AddLog("IOException" );
				} catch (FormatException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
					AddLog("FormatException" );
				}
			}
		}
	}
	private void AddLog(String strLog) {
		SimpleDateFormat formatter = new SimpleDateFormat("HH:mm:ss");
		Date curDate = new Date(System.currentTimeMillis());// 獲取當(dāng)前時(shí)間
		String strDate = formatter.format(curDate);
		if (null == m_edtLog)
			return;
		String strLogs = m_edtLog.getText().toString().trim();
		if (strLogs.equals("")) {
			strLogs = strDate + " " + strLog;
		} else {
			strLogs += "\r\n" + strDate + " " + strLog;
		}
		m_edtLog.setText(strLogs);
	}
	public void OnClearLogListener(View arg0) {
		if (null == m_edtLog)
			return;
		m_edtLog.setText("");
	}
	public void OnSetNfcListener(View arg0) {
		startActivityForResult(new Intent(
				android.provider.Settings.ACTION_WIRELESS_SETTINGS), 0);		
	}
	
	public void OnTestListener(View arg0) {
		String strWriteText = "春眠不覺曉";
		if(null == m_NfcIntent) return;
		if (NfcAdapter.ACTION_TECH_DISCOVERED.equals(m_NfcIntent.getAction())) {
			Tag tagFromIntent = m_NfcIntent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
			Ndef ndef = Ndef.get(tagFromIntent);
			if (ndef != null) {
				NdefMessage ndefMessage = createMessage(strWriteText);
				try {
					ndef.connect();
					// READ
					NdefMessage msg = ndef.getNdefMessage();
					NdefRecord[] records = msg.getRecords();
					// NdefMessage nmsg = (NdefMessage) msgs[0];
					NdefRecord record = records[0];
					String resultStr = "";
					if (record.getTnf() == NdefRecord.TNF_WELL_KNOWN) {
						if (Arrays
								.equals(record.getType(), NdefRecord.RTD_TEXT)) {
							byte[] payload = record.getPayload();
							if (payload == null)
								return;
							try {
								String textEString = ((payload[0] & 0x80) == 0) ? "UTF-8"
										: "UTF-16";
								int languageCodeLength = payload[0] & 0x3f;
								resultStr = new String(payload,
										languageCodeLength + 1, payload.length
												- languageCodeLength - 1,
										textEString);
								AddLog("Read:" + resultStr);
							} catch (Exception e) {
								e.printStackTrace();
							}
						}
					}
					// WRITE
					ndef.writeNdefMessage(ndefMessage);
					AddLog("WRITE:" + strWriteText);
					ndef.close();
				} catch (IOException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (FormatException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
}

以為內(nèi)容是在Android設(shè)備上接入L3-U 免驅(qū)NFC讀寫器的范例，讀寫NFC標(biāo)簽需要安裝NDEF格式進(jìn)行處理，這部分后面單獨(dú)列出來分享給大家。