java - 如何将 NDEF 记录写入 NFC 标签？

Question

如何将 NDEF 消息写入 NFC 标签？
我必须更改 list 文件吗？
到目前为止，我有生成 NDEF 消息的代码:

    public NdefRecord createTextRecord(String payload, Locale locale, boolean encodeInUtf8) {
    byte[] langBytes = locale.getLanguage().getBytes(Charset.forName("US-ASCII"));
    Charset utfEncoding = encodeInUtf8 ? Charset.forName("UTF-8") : Charset.forName("UTF-16");
    byte[] textBytes = payload.getBytes(utfEncoding);
    int utfBit = encodeInUtf8 ? 0 : (1 << 7);
    char status = (char) (utfBit + 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);
    NdefRecord record = new NdefRecord(NdefRecord.TNF_WELL_KNOWN,
            NdefRecord.RTD_TEXT, new byte[0], data);
    return record;
}

如何发现 TAG？
有人可以帮我吗？

Answer 1

我会忽略谷歌文档所说的阅读 https://developer.android.com/guide/topics/connectivity/nfc/nfc并在 https://developer.android.com/guide/topics/connectivity/nfc/advanced-nfc#read-write 进行读/写因为这为写入标签提供了非常糟糕的用户体验，并且由于用户行为导致许多失败的写入。
要使用 Android 可靠地写入 NFC，您应该使用更新更好的 enableReaderMode API https://developer.android.com/reference/android/nfc/NfcAdapter
使用这个较新的 API 可以减少失败的写入和损坏的卡，因为您可以控制通知声音何时发生。与老Intent基于系统的系统应用程序暂停您的应用程序，然后读取卡片并发出通知声音，然后用户在您的应用程序恢复之前采取卡片方式并有机会处理卡片数据并写入卡片。
使用较新的 enableReaderMode API你关闭系统通知声音，你的应用程序永远不会暂停读取NFC卡，然后你可以读取和写入卡，然后当你成功写入卡​​时，你可以自己发出通知声音。
因为任何错误都是无声的，所以用户将继续尝试出示卡片，直到成功通知。不需要在每次出示单张卡片或出示不同卡片时都写入相同消息的附加逻辑。
一些示例代码(改编自我的应用程序进行 NFC 低级读写(不是 Ndef Tag 技术))

public class NFCActivity extends AppCompatActivity implements NfcAdapter.ReaderCallback{

private NfcAdapter mNfcAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_nfc);

        mNfcAdapter = NfcAdapter.getDefaultAdapter(this);

        // Rest of Activity setup
     }

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

        if(mNfcAdapter!= null) {
            Bundle options = new Bundle();
            // Work around for some broken Nfc firmware implementations that poll the card too fast
            options.putInt(NfcAdapter.EXTRA_READER_PRESENCE_CHECK_DELAY, 250);

            // Enable ReaderMode for all types of card and disable platform sounds
            mNfcAdapter.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);
        }

    }

    @Override
    protected void onPause() {
        super.onPause();
        if(mNfcAdapter!= null)
            mNfcAdapter.disableReaderMode(this);
    }
    
   // This method is run in another thread when a card is discovered
   // !!!! This method cannot cannot direct interact with the UI Thread
   // Use `runOnUiThread` method to change the UI from this method
   public void onTagDiscovered(Tag tag) {

      // Read and or write to Tag here to the appropriate Tag Technology type class
      // in this example the card should be an Ndef Technology Type 
      Ndef mNdef = Ndef.get(tag);

      // Check that it is an Ndef capable card
      if (mNdef!= null) {

      // If we want to read
      // As we did not turn on the NfcAdapter.FLAG_READER_SKIP_NDEF_CHECK
      // We can get the cached Ndef message the system read for us.

      NdefMessage mNdefMessage = mNdef.getCachedNdefMessage();


      // Or if we want to write a Ndef message

      // Create a Ndef Record
      NdefRecord mRecord = NdefRecord.createTextRecord("en","English String");

      // Add to a NdefMessage
      NdefMessage mMsg = new NdefMessage(mRecord);
      
      // Catch errors
      try {
          mNdef.connect();
          mNdef.writeNdefMessage(mMsg);

          // Success if got to here
          runOnUiThread(() -> {
             Toast.makeText(getApplicationContext(),
               "Write to NFC Success",
               Toast.LENGTH_SHORT).show();
          });

          // Make a Sound
          try {
              Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
              Ringtone r = RingtoneManager.getRingtone(getApplicationContext(),
                  notification);
              r.play();
              } catch (Exception e) {
                 // Some error playing sound
              }
          
      } catch (FormatException e) {
        // if the NDEF Message to write is malformed
      } catch (TagLostException e) {
        // Tag went out of range before operations were complete
      } catch (IOException e){
        // if there is an I/O failure, or the operation is cancelled
      } finally {
        // Be nice and try and close the tag to
        // Disable I/O operations to the tag from this TagTechnology object, and release resources. 
         try {
                mNdef.close();
             } catch (IOException e) {
               // if there is an I/O failure, or the operation is cancelled
             }
      }

   }

}