protected override void OnNewIntent(Intent intent)
{
if (_inWriteMode)
{
_inWriteMode = false;
var tag = intent.GetParcelableExtra(NfcAdapter.ExtraTag) as Tag;
if (tag == null)
{
return;
}
// These next few lines will create a payload (consisting of a string)
// and a mimetype. NFC record are arrays of bytes.
var message = _inputText.Text += " " + DateTime.Now.ToString("HH:mm:ss dd/M/yyyy");
_outputText.Text = message;
var payload = Encoding.ASCII.GetBytes(message);
var mimeBytes = Encoding.ASCII.GetBytes(ViewIsolationType);
var isolationRecord = new NdefRecord(NdefRecord.TnfMimeMedia, mimeBytes, new byte[0], payload);
var ndefMessage = new NdefMessage(new[] { isolationRecord });
TryAndFormatTagWithMessage(tag, ndefMessage);
if (!TryAndWriteToTag(tag, ndefMessage))
{
// Maybe the write couldn't happen because the tag wasn't formatted?
TryAndFormatTagWithMessage(tag, ndefMessage);
}
}
}
/// <summary>
/// This method is called when an NFC tag is discovered by the application.
/// </summary>
/// <param name="intent"></param>
protected override void OnNewIntent(Intent intent)
{
if (_inWriteMode)
{
_inWriteMode = false;
var tag = intent.GetParcelableExtra(NfcAdapter.ExtraTag) as Tag;
if (tag == null)
{
return;
}
// These next few lines will create a payload (consisting of a string)
// and a mimetype. NFC record are arrays of bytes.
var payload = Encoding.ASCII.GetBytes(GetRandomHominid());
var mimeBytes = Encoding.ASCII.GetBytes(ViewApeMimeType);
var apeRecord = new NdefRecord(NdefRecord.TnfMimeMedia, mimeBytes, new byte[0], payload);
var ndefMessage = new NdefMessage(new[] { apeRecord });
if (!TryAndWriteToTag(tag, ndefMessage))
{
// Maybe the write couldn't happen because the tag wasn't formatted?
TryAndFormatTagWithMessage(tag, ndefMessage);
}
}
}
public NdefMessage CreateNdefMessage (NfcEvent evt)
{
DateTime time = DateTime.Now;
var text = ("Beam me up!\n\n" +
"Beam Time: " + time.ToString ("HH:mm:ss"));
NdefMessage msg = new NdefMessage (
new NdefRecord[] { CreateMimeRecord (
"application/com.example.android.beam", Encoding.UTF8.GetBytes (text))
/**
* The Android Application Record (AAR) is commented out. When a device
* receives a push with an AAR in it, the application specified in the AAR
* is guaranteed to run. The AAR overrides the tag dispatch system.
* You can add it back in to guarantee that this
* activity starts when receiving a beamed message. For now, this code
* uses the tag dispatch system.
*/
//,NdefRecord.CreateApplicationRecord("com.example.android.beam")
});
return msg;
}
private bool TryAndFormatTagWithMessage(Tag tag, NdefMessage ndefMessage)
{
var format = NdefFormatable.Get(tag);
if (format == null)
{
_alertMessage.Text = "Tag does not appear to support NDEF format.";
}
else
{
try
{
format.Connect();
format.Format(ndefMessage);
_alertMessage.Text = "Tag successfully written.";
return true;
}
catch (IOException ioex)
{
_alertMessage.Text = "There was an error trying to format the tag: "+ioex.Message;
}
}
return false;
}
public void WriteTag (NdefLibrary.Ndef.NdefMessage message)
{
if (droidTag == null)
{
throw new Exception("Tag Error: No Tag to write, register to NewTag event before calling WriteTag()");
}
Ndef ndef = GetNdef (droidTag);
if (ndef == null)
{
throw new Exception("Tag Error: NDEF not supported");
}
try
{
ndef.Connect();
RaiseTagConnected (nfcTag);
}
catch
{
throw new Exception("Tag Error: No Tag nearby");
}
if(!ndef.IsWritable)
{
ndef.Close ();
throw new Exception("Tag Error: Tag is write locked");
}
int size = message.ToByteArray ().Length;
if(ndef.MaxSize < size)
{
ndef.Close ();
throw new Exception("Tag Error: Tag is too small");
}
try
{
List<Android.Nfc.NdefRecord> records = new List<Android.Nfc.NdefRecord>();
for(int i = 0; i< message.Count;i++)
{
if(message[i].CheckIfValid())
records.Add(new Android.Nfc.NdefRecord(Android.Nfc.NdefRecord.TnfWellKnown,message[i].Type,message[i].Id,message[i].Payload));
else
{
throw new Exception("NDEFRecord number " + i + "is not valid");
}
};
Android.Nfc.NdefMessage msg = new Android.Nfc.NdefMessage(records.ToArray());
ndef.WriteNdefMessage(msg);
}
catch (TagLostException tle)
{
throw new Exception("Tag Lost Error: " + tle.Message);
}
catch (IOException ioe)
{
throw new Exception("Tag IO Error: " + ioe.ToString());
}
catch (Android.Nfc.FormatException fe)
{
throw new Exception("Tag Format Error: " + fe.Message);
}
catch (Exception e)
{
throw new Exception("Tag Error: " + e.ToString());
}
finally
{
ndef.Close ();
RaiseTagTagDisconnected (nfcTag);
}
}
private bool TryAndWriteToTag(Tag tag, NdefMessage ndefMessage)
{
// This object is used to get information about the NFC tag as
// well as perform operations on it.
var ndef = Ndef.Get(tag);
if (ndef != null)
{
ndef.Connect();
// Once written to, a tag can be marked as read-only - check for this.
if (!ndef.IsWritable)
{
_alertMessage.Text = "Tag is read-only.";
}
// NFC tags can only store a small amount of data, this depends on the type of tag its.
var size = ndefMessage.ToByteArray().Length;
if (ndef.MaxSize < size)
{
_alertMessage.Text = "Tag doesn't have enough space.";
}
ndef.WriteNdefMessage(ndefMessage);
_alertMessage.Text = "Succesfully wrote tag.";
return true;
}
return false;
}
/// <summary>
///
/// </summary>
/// <param name="tag"></param>
/// <param name="ndefMessage"></param>
/// <returns></returns>
private bool TryAndFormatTagWithMessage(Tag tag, NdefMessage ndefMessage)
{
var format = NdefFormatable.Get(tag);
if (format == null)
{
DisplayMessage("Tag does not appear to support NDEF format.");
}
else
{
try
{
format.Connect();
format.Format(ndefMessage);
DisplayMessage("Tag successfully written.");
return true;
}
catch (IOException ioex)
{
var msg = "There was an error trying to format the tag.";
DisplayMessage(msg);
Log.Error(Tag, ioex, msg);
}
}
return false;
}
public void WriteTag(NdefLibrary.Ndef.NdefMessage message)
{
if (droidTag == null)
{
throw new Exception("Tag Error: No Tag to write, register to NewTag event before calling WriteTag()");
}
Ndef ndef = GetNdef(droidTag);
if (ndef == null)
{
throw new Exception("Tag Error: NDEF not supported");
}
try
{
ndef.Connect();
RaiseTagConnected(nfcTag);
}
catch
{
throw new Exception("Tag Error: No Tag nearby");
}
if (!ndef.IsWritable)
{
ndef.Close();
throw new Exception("Tag Error: Tag is write locked");
}
int size = message.ToByteArray().Length;
if (ndef.MaxSize < size)
{
ndef.Close();
throw new Exception("Tag Error: Tag is too small");
}
try
{
List <Android.Nfc.NdefRecord> records = new List <Android.Nfc.NdefRecord>();
for (int i = 0; i < message.Count; i++)
{
if (message[i].CheckIfValid())
{
records.Add(new Android.Nfc.NdefRecord(Android.Nfc.NdefRecord.TnfWellKnown, message[i].Type, message[i].Id, message[i].Payload));
}
else
{
throw new Exception("NDEFRecord number " + i + "is not valid");
}
}
;
Android.Nfc.NdefMessage msg = new Android.Nfc.NdefMessage(records.ToArray());
ndef.WriteNdefMessage(msg);
}
catch (TagLostException tle)
{
throw new Exception("Tag Lost Error: " + tle.Message);
}
catch (IOException ioe)
{
throw new Exception("Tag IO Error: " + ioe.ToString());
}
catch (Android.Nfc.FormatException fe)
{
throw new Exception("Tag Format Error: " + fe.Message);
}
catch (Exception e)
{
throw new Exception("Tag Error: " + e.ToString());
}
finally
{
ndef.Close();
RaiseTagTagDisconnected(nfcTag);
}
}
