我正在尝试在 Android 手机（Nexus 4）上实现不同的 NfcV 命令。目前，我正在使用这些标签。根据数据表，它们应该支持“安静”命令。
不幸的是，我无法让下面的源代码正常工作。我希望“保持安静”命令之后的“库存”和“读取单个块”命令会失败，因为这两个命令都没有被寻址，处于安静状态的标签应该忽略。但我仍然从标签中得到包含 UID 或有效负载的正确答案。
此外，我通过执行“保持安静”命令得到“标签丢失”异常。但是，根据 ISO 15693-3，标签不应对此命令做出响应，这无论如何都可能导致此异常。
不过，我猜这段代码中的“保持安静”命令有问题，但我不知道是什么。
任何帮助表示赞赏。
源代码：
NfcV nfcv = NfcV.get(mtag);
try{
nfcv.connect(); //Connect
} catch(IOException e){
mUIDs = mUIDs + "\nConnection Error 1";
}
byte[] response1 = {(byte) 0x00};
try{
byte[] UIDreq1 = InventoryRequest(); //Inventory Request
response1 = nfcv.transceive(UIDreq1);
} catch(IOException e){
mUIDs = mUIDs + "\nInventory Error 1";
}
mUIDs = mUIDs +"\n" + bytesToHex(response1);
byte[] UID = response2UID(response1);
mUIDs = mUIDs + "\n" + bytesToHex(UID);
try{
byte[] command = ReadSingleBlockUnadressed((byte) 0x04); //Reading Single Block
byte[] data = nfcv.transceive(command);
mUIDs = mUIDs +"\n"+bytesToHex(data);
}catch(IOException e){
Log.e("Reading Single Block", e.getMessage());
mUIDs = mUIDs + "\nReading Error";
}
try{
try{
byte[] command = StayQuiet(UID); //Stay Quiet, SHOULD FAIL
nfcv.transceive(command);
}catch(TagLostException e){
Log.e("Stay Quiet", e.getMessage());
mUIDs = mUIDs + "\nTag was lost.";
}
}catch(IOException x){
mUIDs = mUIDs + "\nStay Quiet Error";
}
try{
byte[] command = ReadSingleBlockUnadressed((byte) 0x04); //Reading Single Block
byte[] data = nfcv.transceive(command);
mUIDs = mUIDs +"\n"+bytesToHex(data);
}catch(IOException e){
Log.e("Reading Single Block", e.getMessage());
mUIDs = mUIDs + "\nReading Error";
}
try{
byte[] UIDreq2 = InventoryRequest(); //Inventory Request, SHOULD FAIL
byte[] response2 = nfcv.transceive(UIDreq2);
mUIDs = mUIDs +"\n" + bytesToHex(response2);
} catch(IOException e){
mUIDs = mUIDs + "\nInventory Error 2";
}
try{
nfcv.close(); //Disconnect
} catch(IOException x){
mUIDs = mUIDs + "\nDisconnection Error 1";
}
mTagTextView.setText(mUIDs);
具有以下功能：
final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();
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);
}
private byte[] response2UID(byte[] response){
byte[] UID = new byte[response.length-2];
for(int i = 2; i < response.length; i++){
UID[i-2]=response[i];
}
return UID;
}
private byte[] ReadSingleBlockUnadressed(byte blocknumber){
return new byte[] {(byte) 0x00, (byte) 0x20, blocknumber};
}
private byte[] StayQuiet(byte[] UID){
byte[] beQuiet = new byte[] {(byte) 0x04, (byte) 0x02};
byte[] command = combine(beQuiet, UID);
return command;
}
private byte[] InventoryRequest(){
return new byte[] { (byte) 0x24, (byte) 0x01, (byte) 0x00};
}