/*
* Potentially useful links
* https://stackoverflow.com/questions/36270238/android-nfc-ndef-writendefmessage-throws-ioexception-and-erases-tag-data
* https://stackoverflow.com/questions/40288795/android-nfca-connect-nfca-transceive-nfca-settimeout-and-nfca-getmaxtran
* https://stackoverflow.com/questions/29718618/get-the-data-payload-of-a-tag
* https://stackoverflow.com/questions/42819027/nfca-transceive-commands-documentation-nfc-a-iso-14443-3a*
*/
public void Callback(object obj)
{
if (obj is Intent intent)
{
Logging.Log(LogType.Information, $"Callback object is of type 'Intent'");
Tag rawTag = intent.GetParcelableExtra(NfcAdapter.ExtraTag) as Tag;
NfcA tag = NfcA.Get(rawTag);
tag.Connect();
byte[] result = tag.Transceive(CommandFactory.Instance().GetByteCommand(NfcByteCommand.Select));
if (!(result[0] == (byte)0x90 && result[1] == (byte)0x00))
{
throw new IOException("could not select applet");
}
result = tag.Transceive(CommandFactory.Instance().GetByteCommand(NfcByteCommand.GetString));
int len = result.Length;
if (!(result[len - 2] == (byte)0x90 && result[len - 1] == (byte)0x00))
{
throw new RuntimeException("could not retrieve msisdn");
}
byte[] data = new byte[len - 2];
Array.Copy(result, data, len - 2);
var str = Encoding.Default.GetString(data).Trim();
tag.Close();
}
}
public byte[] NfcA_WritePage(NfcA nfca, byte Page)
{
return(nfca.Transceive(new byte[2] {
NfcA_Write_Key, Page
}));
}