Question

我在Android上使用NFC时遇到问题。我想把一些数据发送到M1卡。我可以使用transceive()方法发送命令。但是transceive()方法有一个byte[]参数，一个字节是8位。我想将0b1000000（短帧）发送到我的M1卡。如何发送到M1卡？

 /**
 * Send raw NfcA data to a tag and receive the response.
 *
 * <p>This is equivalent to connecting to this tag via {@link NfcA}
 * and calling {@link NfcA#transceive}. Note that all MIFARE Classic
 * tags are based on {@link NfcA} technology.
 *
 * <p>Use {@link #getMaxTransceiveLength} to retrieve the maximum number of bytes
 * that can be sent with {@link #transceive}.
 *
 * <p>This is an I/O operation and will block until complete. It must
 * not be called from the main application thread. A blocked call will be canceled with
 * {@link IOException} if {@link #close} is called from another thread.
 *
 * <p class="note">Requires the {@link android.Manifest.permission#NFC} permission.
 *
 * @see NfcA#transceive
 */
public byte[] transceive(byte[] data) throws IOException {
    return transceive(data, true);
}

我的代码是：

 /**
 * Write a block of 16 byte data to tag.
 * @param sectorIndex The sector to where the data should be written
 * @param blockIndex The block to where the data should be written
 * @param data 16 byte of data.
 * @param key The MIFARE Classic key for the given sector.
 * @param useAsKeyB If true, key will be treated as key B
 * for authentication.
 * @return The return codes are:<br />
 * <ul>
 * <li>0 - Everything went fine.</li>
 * <li>1 - Sector index is out of range.</li>
 * <li>2 - Block index is out of range.</li>
 * <li>3 - Data are not 16 bytes.</li>
 * <li>4 - Authentication went wrong.</li>
 * <li>-1 - Error while writing to tag.</li>
 * </ul>
 * @see #authenticate(int, byte[], boolean)
 */
public int writeBlock(int sectorIndex, int blockIndex, byte[] data,
        byte[] key, boolean useAsKeyB) {
    if (getSectorCount()-1 < sectorIndex) {
        return 1;
    }
    if (mMFC.getBlockCountInSector(sectorIndex)-1 < blockIndex) {
        return 2;
    }
    if (data.length != 16) {
        return 3;
    }
    int block = mMFC.sectorToBlock(sectorIndex) + blockIndex;

    // write chinese card
    if (block == 0) {
        // Write block.
        try {
            mMFC.transceive(new byte[]{(byte)0x50, (byte)0x00, (byte)0x57, (byte)0xCD});
            mMFC.transceive(new byte[]{(byte)0x40}); // TODO: here need send 0b1000000(7 bit) , not 0b01000000(8 bit)
            mMFC.transceive(new byte[]{(byte)0x43});
            mMFC.writeBlock(block, data);
        } catch (IOException e) {
            Log.e(LOG_TAG, "Error while writing block to tag.", e);
            return -1;
        }
        return 0;
    }

    if (!authenticate(sectorIndex, key, useAsKeyB)) {
        return 4;
    }
    // Write block.
    try {
        mMFC.writeBlock(block, data);
    } catch (IOException e) {
        Log.e(LOG_TAG, "Error while writing block to tag.", e);
        return -1;
    }
    return 0;
}

Answer 1

您尝试做的事情在Android上根本无法实现。 Android NFC API不提供任何直接发送短帧（ISO / IEC 14443-3类型A中定义的7位帧）的方法。

实际上，transceive()的{{1}}方法不仅发送作为参数传递的字节数组。相反，它还会导致CRC校验和自动附加到帧。因此，您只能使用NfcA方法交换普通帧（如ISO / IEC 14443-3 A类中所定义）。

由于您使用的是MIFARE Classic（或者更确切地说是一些UID可更改的克隆），因此您将在支持MIFARE Classic的Android设备（即具有NXP制造的NFC芯片组的设备）上遇到更多限制：如果检测到标签为MIFARE Classic，NFC控制器将切换到一种特殊模式，它可以解释MIFARE Classic命令的高级版本，并自动将它们转换为低级（可能是加密的）版本。这是必要的，因为MIFARE Classic不完全遵循ISO / IEC 14443-3类型A的成帧规则。不幸的是，这通常也会阻止您将任何原始帧直接发送到这些标签。< / p>

如何在Android上通过NFC向M1卡发送7位命令？

1 个答案: