未在 Android 中读取 Nfc 4K 卡详细信息

Question

我想读取 NFC 4K 卡详细信息，它不读取数据，这是我使用的代码，

AndroidManifest.xml

<uses-permission android:name="android.permission.NFC" />
<uses-feature  android:name="android.hardware.nfc" android:required="true" />

        <intent-filter>
            <action android:name="android.nfc.action.NDEF_DISCOVERED" />
            <action android:name="android.nfc.action.TECH_DISCOVERED" />
            <action android:name="android.nfc.action.TAG_DISCOVERED" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="text/plain" />
        </intent-filter>
        <meta-data android:name="android.nfc.action.TECH_DISCOVERED" android:resource="@xml/nfc_tech_filter" />
    </activity>

nfc_tech_filter.xml

<?xml version="1.0" encoding="utf-8"?>
<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>

MainActivity.java

public class MainActivity extends Activity implements NfcAdapter.ReaderCallback {
public static final String TAG = " --NFC-- " + MainActivity.class.getSimpleName();

private NfcAdapter nfcAdapter;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    nfcAdapter = NfcAdapter.getDefaultAdapter(this);
    if (nfcAdapter == null) {
        showToast("No NFC found...");
    } else {
        showToast("NFC Enables Device...");
        enableReaderMode();
    }
}

@Override
public void onResume() {
    super.onResume();
    showToast("On Resume...");
    enableReaderMode();

}

@Override
protected void onPause() {
    super.onPause();
    showToast("On Pause...");
    disableReaderMode();
}


private void showToast(String message) {
    Log.d(TAG, message);
    try {
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
    } catch (Exception e) {
        showToast("Show Toast Exception : " + message);
    }
}


private void enableReaderMode() {
    showToast("Enabling reader mode...");
    Activity activity = MainActivity.this;
    nfcAdapter = NfcAdapter.getDefaultAdapter(activity);
    if (nfcAdapter != null) {
        nfcAdapter.enableReaderMode(activity, this,  Integer.MAX_VALUE, null);
    }
}

private void disableReaderMode() {
    showToast("Disabling reader mode...");
    Activity activity = MainActivity.this;
    nfcAdapter = NfcAdapter.getDefaultAdapter(activity);
    if (nfcAdapter != null) 
        nfcAdapter.disableReaderMode(activity);
}


@Override
public void onTagDiscovered(Tag tag) {
    Log.d(TAG, "New tag discovered...");
}
@Override
protected void onNewIntent(Intent intent) {
    Log.d(TAG, "New Intent...");
    super.onNewIntent(intent);
}

}

Answer 1

您没有在 onNewIntent() 中处理您的意图数据。每当您扫描 NFC 卡时，都会调用 onNewIntent()。 像下面的例子：

@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
Log.d(TAG, "New Intent...");
handleIntent(intent);
}


private void handleIntent(Intent intent) {
val bundle = intent.extras
    if (bundle != null) {
        
Log.e(TAG,intent.getParcelableExtra(NfcAdapter.EXTRA_TAG))
    }
}

已编辑

添加适配器后需要从 onResume() 调用该方法。

private fun setupForegroundDispatch(activity : Activity, adapter 
    : NfcAdapter) {
    val intent = Intent(activity.applicationContext, 
    activity.javaClass)
    intent.flags = Intent.FLAG_ACTIVITY_SINGLE_TOP
    val pendingIntent = 
    PendingIntent.getActivity(activity.applicationContext, 0, 
    intent, 0)
    //        val filters = arrayOfNulls<IntentFilter>(1)
    //        val techList = arrayOf<Array<String>>()
    val ndef = IntentFilter(NfcAdapter.ACTION_TECH_DISCOVERED)
    val filters = arrayOf(ndef)
    //        val techList = arrayOf<Array<String>>()
    val techList = arrayOf(arrayOf(NfcV::class.java.name))

    // Notice that this is the same filter as in our manifest.
    filters[0] = IntentFilter()
    filters[0].addAction(NfcAdapter.ACTION_NDEF_DISCOVERED)
    filters[0].addCategory(Intent.CATEGORY_DEFAULT)
    try {
        filters[0].addDataType(MIME_TEXT_PLAIN)
    }
    catch (e : IntentFilter.MalformedMimeTypeException) {
        throw RuntimeException("Check your mime type.")
    }
    adapter.enableForegroundDispatch(activity, pendingIntent, 
   filters, techList)
}

如下：

private void enableReaderMode() {
showToast("Enabling reader mode...");
Activity activity = MainActivity.this;
nfcAdapter = NfcAdapter.getDefaultAdapter(activity);
if (nfcAdapter != null) {
    nfcAdapter.enableReaderMode(activity, this,  
 Integer.MAX_VALUE, null);
 setupForegroundDispatch(this,nfcAdapter);
}
}

Follow this tutorial for more info

Answer 2

当您使用enableReaderMode 时，您不需要onNewIntent 方法。

清单中的intent-filter 和 nfc_tech_filter.xml 也可能不需要（如果您不希望应用程序在未运行的情况下由 NFC 标签启动，则不需要它们，那么您将处理 NFC Intent在onCreate)

你没有做的是正确设置enableReaderMode。

@Override
    protected void onResume() {
        super.onResume();

        if(nfcAdapter!= null && nfcAdapter.isEnabled) {
            Bundle options = new Bundle();
            options.putInt(NfcAdapter.EXTRA_READER_PRESENCE_CHECK_DELAY, 250);

            nfcAdapter.enableReaderMode(this,
                    this,
                    NfcAdapter.FLAG_READER_NFC_A |
                            NfcAdapter.FLAG_READER_NFC_B |
                            NfcAdapter.FLAG_READER_NFC_F |
                            NfcAdapter.FLAG_READER_NFC_V |
                            NfcAdapter.FLAG_READER_NFC_BARCODE |
                            NfcAdapter.FLAG_READER_NO_PLATFORM_SOUNDS,
                    options);
        }

    }

如果您想生成自己的阅读通知而不是操作系统执行此操作，则关闭 NfcAdapter.FLAG_READER_NO_PLATFORM_SOUNDS 是可选的。

请注意，在写入 NFC 标签时，enableReaderMode 的较新 NFC API 为您提供了比旧 enableForegroundDispatch 更多的控制权，并且比 enableForegroundDispatch 更可靠，并且它没有 @ 的一些负面影响987654331@，所以我建议始终使用enableReaderMode，除非你想支持真正旧的 API

另请注意，不建议使用 Mifare 4K 卡，因为它们是专有格式，并非所有 Android 硬件都支持（无论您使用哪种 API）