Android实现读取NFC卡的编号

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.nfc"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-permission android:name="android.permission.NFC" />
 
    <uses-feature
        android:name="android.hardware.nfc"
        android:required="true" />
 
    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="17" />
 
    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:launchMode="singleTask"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.nfc.MainActivity"
            android:label="@string/app_name" >
            <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.TECH_DISCOVERED" />
            </intent-filter>
 
            <meta-data
                android:name="android.nfc.action.TECH_DISCOVERED"
                android:resource="@xml/nfc_tech_filter" />
 
        </activity>
    </application>
 
</manifest>

<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
    <tech-list>
        <tech>android.nfc.tech.IsoDep</tech>
        <tech>android.nfc.tech.NfcA</tech>        
        <tech>android.nfc.tech.NfcB</tech>
        <tech>android.nfc.tech.NfcF</tech>
        <tech>android.nfc.tech.NfcV</tech>
        <tech>android.nfc.tech.Ndef</tech>
        <tech>android.nfc.tech.NdefFormatable</tech>
        <tech>android.nfc.tech.MifareClassic</tech>
        <tech>android.nfc.tech.MifareUltralight</tech>
    </tech-list>
</resources>

class NFCCard {
 
 private Activity context;
 private PendingIntent pendingIntent;
 private NfcAdapter adapter;
 private IntentFilter[] intentFilters;
 private String[][] techLists;
 private final char[] HEX_EXCHANGE = { '0', '1', '2', '3', '4', '5', '6',
   '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
 
 public NFCCard(Context context) {
  this.context = (Activity) context;
 }
 
 void init() {
 
  adapter = NfcAdapter.getDefaultAdapter(context);
  // 创建一个PendingIntent对象，当Android系统扫描到标签时，则会填充到这个对象。
  pendingIntent = PendingIntent.getActivity(context, 0, new Intent(
    context, context.getClass())
    .addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);
  IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
  try {
   ndef.addDataType("*/*");
  } catch (MalformedMimeTypeException e) {
   throw new RuntimeException("fail", e);
  }
  intentFilters = new IntentFilter[] { ndef, };
  techLists = new String[][] { new String[] { MifareClassic.class
    .getName() } };
 }
 
 public boolean open() {
  // TODO 打开NfcAdapter，已打开则返回true。应在onResume()中调用
  if (adapter != null)
   adapter.enableForegroundDispatch(context, pendingIntent,
     intentFilters, techLists);
  return adapter.isEnabled();
 }
 
 public boolean close() {
  // TODO 关闭NfcAdapter，已关闭则返回true
  if (adapter != null)
   adapter.disableForegroundDispatch(context);
  return !adapter.isEnabled();
 }
 
 public String getId(Intent intent) {
  // TODO　获取NFC卡的编号。应在onNewIntent()中调用
  Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
  return toHexString(tagFromIntent.getId(), 0,
    tagFromIntent.getId().length);
 }
 
 private String toHexString(byte[] d, int s, int n) {
  // TODO 转换为十六进制形式的字符串
  final char[] ret = new char[n * 2];
  final int e = s   n;
  int x = 0;
  for (int i = s; i < e;   i) {
   final byte v = d[i];
   ret[x  ] = HEX_EXCHANGE[0x0F & (v >> 4)];
   ret[x  ] = HEX_EXCHANGE[0x0F & v];
  }
  return new String(ret);
 }