Question

如何从NFC标签中读取和显示NDEF消息？请帮我。任何人都可以提供示例源代码来读取Nfc标签吗？

Answer 1

1）Android上NFC的一般描述是here
2）NFCDemo是here
3）非常好的信息也是here
4）“Zigurd Mednieks”中的“Programming Android”一书中有一章关于NFC
BR
斯登

Answer 2

我们有两个阅读nfc卡的选项。

从缓存中读取

   Ndef ndef = Ndef.get(tag);
    if (ndef == null) {
        // NDEF is not supported by this Tag. 
        return null;
    }

    NdefMessage ndefMessage = ndef.getCachedNdefMessage();

    if (ndefMessage == null) {
        mTextView.setText("The tag is empty !");
        return null;
    }

    NdefRecord[] records = ndefMessage.getRecords();
    for (NdefRecord ndefRecord : records) {
        if (ndefRecord.getTnf() == NdefRecord.TNF_WELL_KNOWN && Arrays.equals(ndefRecord.getType(), NdefRecord.RTD_TEXT)) {
            try {
                return readText(ndefRecord);
            } catch (UnsupportedEncodingException e) {
                Log.e(TAG, "Unsupported Encoding", e);
            }
        }
    }

使用

public void readFromTag(Intent intent){

    Ndef ndef = Ndef.get(detectedTag);


    try{
        ndef.connect();

        txtType.setText(ndef.getType().toString());
        txtSize.setText(String.valueOf(ndef.getMaxSize()));
        txtWrite.setText(ndef.isWritable() ? "True" : "False");
        Parcelable[] messages = intent.getParcelableArrayExtra(NfcAdapter.EXTRA_NDEF_MESSAGES);

        if (messages != null) {
            NdefMessage[] ndefMessages = new NdefMessage[messages.length];
            for (int i = 0; i < messages.length; i++) {
                ndefMessages[i] = (NdefMessage) messages[i];
            }
            NdefRecord record = ndefMessages[0].getRecords()[0];

            byte[] payload = record.getPayload();
            String text = new String(payload);
            txtRead.setText(text);


            ndef.close();

        }
    }
    catch (Exception e) {
        Toast.makeText(getApplicationContext(), "Cannot Read From Tag.", Toast.LENGTH_LONG).show();
    }
}

如何在android中读取Nfc标签？

2 个答案: