Android开发实现NFC刷卡读取的两种方式

<!--权限要加，这是一个普通权限，不需要动态申请，但是在小米手机里需要动态申请-->
     <uses-permission android:name="android.permission.NFC" />
   
     <uses-feature
        android:name="android.hardware.nfc"
        android:required="false" />
 
     <application> 
        ...   
        <activity
            android:name=".NfcActivity"
            android:launchMode="singleTask"
            android:screenOrientation="portrait"
            android:theme="@android:style/Theme.Translucent">
            <!--透明主题，把刷卡变成一个无感知的过程-->
            <intent-filter>
                <action android:name="android.nfc.action.NDEF_DISCOVERED" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.nfc.action.TAG_DISCOVERED" />
 
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.nfc.action.TECH_DISCOVERED" />
                <!--使用这个过滤器 这里其实还要用 meta-data 配置一下标签过滤，-->
                <!--我项目中是 NDEF_DISCOVERED 这个TECH_DISCOVERED形同虚设-->
            </intent-filter>
            <meta-data
                android:name="android.nfc.action.TECH_DISCOVERED"
                android:resource="@xml/nfc_tech" />
        </activity>
</application> 

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:android="http://schemas.android.com/apk/res/android">
 
    <tech-list>
        <tech>android.nfc.tech.Ndef</tech>
        <tech>android.nfc.tech.NfcA</tech>
    </tech-list>
 
    <tech-list>
        <tech>android.nfc.tech.NfcB</tech>
    </tech-list>
    <tech-list>
        <tech>android.nfc.tech.NfcF</tech>
    </tech-list>
</resources>

public class NfcActivity extends Activity {
 
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nfc);
        initData();
    }
 
    
    private void initData() {
        NfcAdapter adapter = NfcAdapter.getDefaultAdapter(this);
        if (null == adapter) {
            Toast.makeText(this, "不支持NFC功能", Toast.LENGTH_SHORT).show();
        } else if (!adapter.isEnabled()) {
            Intent intent = new Intent(Settings.ACTION_NFC_SETTINGS);
            // 根据包名打开对应的设置界面
            startActivity(intent);
        }
 
        //我项目中是拿了NFC卡的tag中的id数据，这根据具体情况来；
        // 可以在NfcAdapter源码中查看，具体能拿到哪些数据
        Tag tag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
        String id = bytesToHex(tag.getId());
 
        //TODO 目前我这边项目中，拿到数据后，通过EventBus分发到对应的activity，当然也能使用其他分发响应方式，
 
        //关闭动画，毕竟对用户来说，刷卡应当是一个无感知的过程
        overridePendingTransition(0, 0);
        finish();
    }
 
    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        initData();
    }
 
    
    private static String bytesToTenNum(byte[] class="lazy" data-src) {
        StringBuilder stringBuilder = new StringBuilder();
        if (class="lazy" data-src == null || class="lazy" data-src.length <= 0) {
            return null;
        }
        char[] buffer = new char[2];
        for (int i = 0; i < class="lazy" data-src.length; i++) {
            buffer[1] = Character.toUpperCase(Character.forDigit(
                    (class="lazy" data-src[i] >>> 4) & 0x0F, 16));
            buffer[0] = Character.toUpperCase(Character.forDigit(class="lazy" data-src[i] & 0x0F,
                    16));
            stringBuilder.append(buffer);
        }
        stringBuilder.reverse();
        BigInteger bigi = new BigInteger(stringBuilder.toString(), 16);
        return bigi.toString();
    }
 
    
    private static String bytesToHex(byte[] class="lazy" data-src){
        StringBuffer sb = new StringBuffer();
        if (class="lazy" data-src == null || class="lazy" data-src.length <= 0) {
            return null;
        }
        String sTemp;
        for (int i = 0; i < class="lazy" data-src.length; i++) {
            sTemp = Integer.toHexString(0xFF & class="lazy" data-src[i]);
            if (sTemp.length() < 2){
                sb.append(0);
            }
            sb.append(sTemp.toUpperCase());
        }
        return sb.toString();
    }
}

public class NfcTestActivity extends AppCompatActivity {
 
    NfcAdapter mNfcAdapter;
    PendingIntent pIntent;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nfc_test);
        initNfc();
        Log.i("FlashTestNFC", "onCreate");
    }
 
    @Override
    protected void onStop() {
        super.onStop();
        Log.i("FlashTestNFC", "onStop");
    }
 
    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i("FlashTestNFC", "onDestroy");
    }
 
    
    private void initNfc(){
        mNfcAdapter = NfcAdapter.getDefaultAdapter(this);
        pIntent = PendingIntent.getActivity(this, 0,
                //在Manifest里或者这里设置当前activity启动模式，否则每次向阳NFC事件，activity会重复创建
                // 当然也要按照具体情况来，你设置成singleTask也不是不行，
                new Intent(this, getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP),
                0);
    }
 
    @Override
    protected void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        //这里必须setIntent，set  NFC事件响应后的intent才能拿到数据
        setIntent(intent);
        Log.i("FlashTestNFC", "onNewIntent");
        Tag tag = getIntent().getParcelableExtra(NfcAdapter.EXTRA_TAG);
 
        //TODO 获取数据进行下一步处理
 
        Log.i("FlashTestNFC--Tag", bytesToHex(tag.getId()));
    }
 
    @Override
    protected void onResume() {
        super.onResume();
        Log.i("FlashTestNFC", "onResume");
        if (mNfcAdapter != null) {
            //添加intent-filter
            IntentFilter ndef = new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED);
            IntentFilter tag = new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED);
            IntentFilter tech = new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED);
            IntentFilter[] filters = new IntentFilter[]{ndef, tag, tech};
 
            //添加 ACTION_TECH_DISCOVERED 情况下所能读取的NFC格式，这里列的比较全，实际我这里是没有用到的，因为测试的卡是NDEF的
            String[][] techList = new String[][]{
                    new String[]{
                            "android.nfc.tech.Ndef",
                            "android.nfc.tech.NfcA",
                            "android.nfc.tech.NfcB",
                            "android.nfc.tech.NfcF",
                            "android.nfc.tech.NfcV",
                            "android.nfc.tech.NdefFormatable",
                            "android.nfc.tech.MifareClassic",
                            "android.nfc.tech.MifareUltralight",
                            "android.nfc.tech.NfcBarcode"
                    }
            };
            mNfcAdapter.enableForegroundDispatch(this, pIntent, filters, techList);
        }
    }
 
    @Override
    protected void onPause() {
        super.onPause();
        Log.i("FlashTestNFC", "onPause");
        if (mNfcAdapter != null) {
            mNfcAdapter.disableForegroundDispatch(this);
        }
    }
 
    
    private static String bytesToHex(byte[] class="lazy" data-src){
        StringBuffer sb = new StringBuffer();
        if (class="lazy" data-src == null || class="lazy" data-src.length <= 0) {
            return null;
        }
        String sTemp;
        for (int i = 0; i < class="lazy" data-src.length; i++) {
            sTemp = Integer.toHexString(0xFF & class="lazy" data-src[i]);
            if (sTemp.length() < 2){
                sb.append(0);
            }
            sb.append(sTemp.toUpperCase());
        }
        return sb.toString();
    }
}