USB免驅NFC讀寫器 Android系統中NFC讀寫范例
- 2019-07-04 14:10:00
- 諾塔斯智能科技 原創
- 4651
由于Android具有良好的開源優勢，可進行深度定制開發。安卓系統市場應用比windows晚，雖然支持的應用不如windows系統多，但由于系統的免費開放性，眾多軟件廠商經過近幾年的開發，已經有越來越多的應用加入進來，目前支持辦公、教學、娛樂已經完全沒有問題。因此，越來越多的行業接受并認可基于Android操作系統的設備。
目前市面上大多數工業控制設備開始采用Android系統了，然而這部分設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，很多行業需要一直可以支持Android系統的可接入Android設備并進行二次開發的NFC讀寫器。因此，L3-U這款NFC讀寫器 應運而生。作為一款采用USB免驅的NFC讀寫器，支持在windows、Android、linux等操作系統，免費提供基于上述各種系統的SDK，方便客戶進行功能擴展和二次開發。
L3-U這款USB免驅動NFC讀寫器已經設計好了USB 驅動，用戶在基于Android系統的設備上只有能獲取USB HOST權限或者采用OTG傳輸就可以使用，無需安裝額外驅動。如果你其它非標準的Android設備，需要提供設備我們進行編譯驅動。以下為標準的具有USB HOST權限的設備接入NFC讀寫器的過程。供大家在進行NFC讀寫器二次開發過程中參考！
1、在項目中對AndroidManifest.xml文件進行配置，獲取相關權限。
<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Activity頁面，用于實現NFC讀寫的功能。NFC讀寫功能實現的代碼如下：
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());// 獲取當前時間
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();
}
}
}
}
}
以為內容是在Android設備上接入L3-U 免驅NFC讀寫器的范例，讀寫NFC標簽需要安裝NDEF格式進行處理，這部分后面單獨列出來分享給大家。
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