你如何在Android上阅读NFC标签的唯一ID？

Question

Tag myTag = (Tag) intent.getParcelableExtra(NfcAdapter.EXTRA_TAG);
Log.i("tag ID", myTag.getId().toString());

这给了我一个像"[B @ 40521c40"这样的ID,但这个ID会改变每次读取.

任何帮助将不胜感激.

谢谢.

Answer 1

你仍然需要将字节转换为字符串:

private String bytesToHexString(byte[] src) {
    StringBuilder stringBuilder = new StringBuilder("0x");
    if (src == null || src.length <= 0) {
        return null;
    }

    char[] buffer = new char[2];
    for (int i = 0; i < src.length; i++) {
        buffer[0] = Character.forDigit((src[i] >>> 4) & 0x0F, 16);  
        buffer[1] = Character.forDigit(src[i] & 0x0F, 16);  
        System.out.println(buffer);
        stringBuilder.append(buffer);
    }

    return stringBuilder.toString();
}

Answer 2

我遇到了类似的问题,可以解决它.问题是转换为字符串.

myTag.getId()返回字节数组.您应该将这些字节转换为十六进制字符串 我使用了stackoverflow.com中的以下函数

    final protected static char[] hexArray = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
public static String bytesToHex(byte[] bytes) {
    char[] hexChars = new char[bytes.length * 2];
    int v;
    for ( int j = 0; j < bytes.length; j++ ) {
        v = bytes[j] & 0xFF;
        hexChars[j * 2] = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    return new String(hexChars);
}