对于android4.1-4.3以下nfc对卡片的读取就是以下代码：

NfcAdapter mAdapter = NfcAdapter.getDefaultAdapter(this);

public void registerReceiver() {

if (mAdapter != null) {

mFilters = new IntentFilter[]{

new IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED),

new IntentFilter(NfcAdapter.ACTION_NDEF_DISCOVERED),

new IntentFilter(NfcAdapter.ACTION_TAG_DISCOVERED)};

mPendingIntent = PendingIntent.getActivity(this, 0,

new Intent(this, this.getClass()).addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP), 0);

try {

mAdapter.enableForegroundDispatch(this, mPendingIntent, mFilters, null);

} catch (Exception e) {

}

}

}

public void unregisterReceiver() {

if (mAdapter != null) {

try {

mAdapter.disableForegroundDispatch(this);

} catch (Exception e) {

}

}

}

然后触发的代码在

protected void onNewIntent(Intent intent) {

Tag tagFromIntent = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);

IsoDep isoDep = IsoDep.get(tagFromIntent);

}

在 AndroidManifest.xml 的相应的activity加上

android:launchMode="singleTask"

而上面适用于android4.4以下的方法在android4.4也是可以运行，

不过会出现有些卡能读写，有些卡无限重连，有些卡两条指令之间不能超过300ms

对于android4.4以上nfc对卡片的读取就是以下代码：api19

public static int READER_FLAGS = NfcAdapter.FLAG_READER_NFC_A | NfcAdapter.FLAG_READER_SKIP_NDEF_CHECK;

private void enableReaderMode() {

Activity activity = getActivity();

NfcAdapter nfc = NfcAdapter.getDefaultAdapter(activity);

Bundle options = new Bundle();

options.putInt(NfcAdapter.EXTRA_READER_PRESENCE_CHECK_DELAY, 5000);//延迟对卡片的检测

if (nfc != null) {

nfc.enableReaderMode(activity, mCardReader, READER_FLAGS, options);

}

}

private void disableReaderMode() {

Activity activity = getActivity();

NfcAdapter nfc = NfcAdapter.getDefaultAdapter(activity);

if (nfc != null) {

nfc.disableReaderMode(activity);

}

}

在onTagDiscovered编写具体的卡片操作

@Override

public void onTagDiscovered(Tag tag) {

IsoDep isoDep = IsoDep.get(tag);

}