如何使用Android的enableReaderMode API將NDEF記錄寫入NFC標籤？

How to Write NDEF Records to NFC Tag Using the enableReaderMode API

Introduction

Writing NDEF records to NFC tags requires a different approach in Android to ensure reliability and avoid failed writes. The older Intent-based system often led to issues due to interrupted reads and silent errors.

Using the enableReaderMode API

The newer enableReaderMode API provides a more robust approach. It disables system notifications, allowing your app to control the timing of sounds and handle the read/write process efficiently. By doing so, you can minimize failed writes and data corruption.

Example Code

The following Java code snippet demonstrates how to use the enableReaderMode API:

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();
            options.putInt(NfcAdapter.EXTRA_READER_PRESENCE_CHECK_DELAY, 250);

            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);
    }

    @Override
    public void onTagDiscovered(Tag tag) {
        Ndef mNdef = Ndef.get(tag);

        if (mNdef!= null) {
            NdefRecord mRecord = NdefRecord.createTextRecord("en", "English String");

            NdefMessage mMsg = new NdefMessage(mRecord);

            try {
                mNdef.connect();
                mNdef.writeNdefMessage(mMsg);

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

                Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
                Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification);
                r.play();

            } catch (Exception e) {
                // Handle errors
            } finally {
                try {
                    mNdef.close();
                } catch (IOException e) {
                    // Handle I/O failure or cancelled operation
                }
            }
        }
    }
}

Additional Notes

• You can read the cached NDEF message by using mNdef.getCachedNdefMessage().
• To avoid silent errors, you should handle all exceptions during read/write operations.
• For Android 12L and above, a SecurityException can be thrown if the Tag object becomes stale.

以上是如何使用Android的enableReaderMode API將NDEF記錄寫入NFC標籤？的詳細內容。更多資訊請關注PHP中文網其他相關文章！