如何使用Nexus 5读取Mifare Ultralight 16位UID

Question

我对Android的NFC很陌生。我需要大量Java代码示例或好的教程，以了解如何使用Nexus 5读取Mifare Ultralight 16位UID

我只知道如何从这里读取Mifare classic卡的标签UID，获得MifareClassic的7位数UID，但没有Mifare Ultralight的示例。

这是获取Mifare Classic UID的另一个示例。Mifare Ultralight需要更改哪些内容以使其读数符合Mifare Ultralight？而且我不理解ByteArrayToHexString（）中执行的操作

byte[] nfcUID = null;
        if (intent != null && (nfcUID = intent.getByteArrayExtra(NfcAdapter.EXTRA_ID)) != null) {

            uid = ByteArrayToHexString(nfcUID);

private String ByteArrayToHexString(byte[] inarray) { // converts byte arrays to string
        int i, j, in;
        String[] hex = {
                "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F"
        };
    String out = "";

    for (j = 0; j < inarray.length; ++j) {
        in = inarray[j] & 0xff;
        i = (in >> 4) & 0x0f;
        out += hex[i];
        i = in & 0x0f;
        out += hex[i];
    }
    return out;
}

非常感谢！

Answer 1

首先，MIFARE Classic标记通常有一个4字节的UID（也称为nUID）。较新的MIFARE Classic标记还具有7字节的UID。MIFARE Ultralight标签始终具有7字节的UID。

此UID是您将从

byte[] uid = intent.getByteArrayExtra(NfcAdapter.EXTRA_ID);

或来自

Tag tag = intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
byte[] uid = tag.getId();

null

public static String convertByteArrayToHexString (byte[] b) {
    if (b != null) {
        StringBuilder s = new StringBuilder(2 * b.length);
        for (int i = 0; i < b.length; ++i) {
            final String t = Integer.toHexString(b[i]);
            final int l = t.length();
            if (l > 2) {
                s.append(t.substring(l - 2));
            } else {
                if (l == 1) {
                    s.append("0");
                }
                s.append(t);
            }
        }
        return s.toString();
    } else {
        return "";
    }
}

public static String convertByteArrayToDecString (byte[] b) {
    if (b != null) {
        BigInteger n = new BigInteger(1, b);
        return n.toString();
    } else {
        return "";
    }
}