read tag UID of a classic mifare 1k or NFC

[abcroverix]

Hello, I'm new in java and android programming.
I need to read the classic mifare 1k or NFC UID
I tried to use the NFC.GeTagtUID from NFC library 1.1 (posted by Sherlock)
I get an array of 4 bytes. First two bytes are the same to the first two byte of the UID (I can read the UID with another device), but the last two bytes are negative numbers and are wrong.

This is the piece of my code:

If NFC.IsNdefIntent(Activity.GetStartingIntent) Then
Dim XID(20) As Byte
XID=NFC.GeTagtUID(Activity.GetStartingIntent)
end if

For example the last two bytes I get are (in decimal): -54,-73,
but the last two bytes in the UID are (in hex): CA, B7.

Someone can explain to me because this happen?
Where I'm wrong?

Many thanks

Fabio

 

[Erel]

Basic4android (and Java) bytes are signed bytes.
So -54 is actually 202 and -73 is 183.

You can use this code to get the unsigned value:

Sub ConvertToUnsigned(b As Byte) As Int
 Return Bit.And(b, 0xFF)
End Sub

 

[abcroverix]

Many thanks Erel!

I forgot to apply that rule to negative numbers!

See you

Fabio

 

[Rafal Galewski]

Problem with If NFC.IsNdefIntent(Activity.GetStartingIntent) Then

Could You share me Your project.
I have a problem with Intent activity.
I want read UID from Mifare 1 K but I have a problem with NFC.IsNdefIntent.
I don't have any success read UID number.

Please help I 'm new in Android apps.

:sign0013:
Thank You advance.

 

[Rafal Galewski]

If NFC.IsNdefIntent(Activity.GetStartingIntent) Then


XID=NFC.GeTagtUID(Activity.GetStartingIntent)


ByteConverter.StringFromBytes(XID,ID)


ToastMessageShow(ID,True)


"If NFC.IsNdefIntent(Activity.GetStartingIntent) Then"
- Never go to IF section, becouse in my opinion start BALayout program debuger and Intent started is MBALayout not my .


:sign0163:

 

[Erel]

It will be an "ndef intent" when you scan such tag.

 

[Rafal Galewski]

It will be an "ndef intent" when you scan such tag.

Yes , I check by IF ndef intent.

But I have to change something in Manifest file ?

Now is like this:

AddActivityText(main, <intent-filter>
<action android:name="android.nfc.action.NDEF_DISCOVERED"/>
<category android:name="android.intent.category.DEFAULT"/>
<data android:mimeType="text/plain" />
</intent-filter>)




Please write for me more details.



Thank You

 

[Erel]

It depends on the mime tag of the NDEF tag.

 

[Rafal Galewski]

It depends on the mime tag of the NDEF tag.

What can I do ?

I want read serial number Mifare 1 K.

Mime type in manifest I have to change for what ?

Could You detailed answer ?:sign0104:

 

[Erel]

The mime type required depends on the mime type of the data stored in the tag.
There is a link in the tutorial to a third party app that will help you see what is the mime type and write new data if needed.

 

[Rafal Galewski]

Problem on Android 4.1.1

I do this in another way on 4.0.4 android.
But now I try to use it on 4.1.1 Android
And this now work correctly.

No UID is read

When I read UID tag Layout - all activity is change position.

What is problem - library ?

How resolve this problem

 

[Erel]

Add the following code and check which intents your activity receives:

Log(Activity.GetStartingIntent)
Log(Activity.GetStartingIntent.ExtrasToString)

 

[Rafal Galewski]

Thank You I try.
When can I read this LOG.

In debugger ?


I update phone from android 4.0.4 to 4.1.1
In my opinion is problem with Mifare classic read UID.

 

[Erel]

In my opinion is problem with Mifare classic read UID

It will only work if you write NDEF data to this tag.

You can see the logs in the Logs tag (IDE right side).

 

[Rafal Galewski]

No I don't have to write Mifare 1k becouse is serial number from chip.
yesterday I correct read serial number - UID.

But when I change version from android 4.0.4 to android 4.1.1 - this function can't work correctly.

I use library NFC 1.1 - with UID read function

 

[Rafal Galewski]

I check which intents your activity receives:

(Intent) Intent { act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 pkg=de.mrsoft.xnfc cmp=de.mrsoft.xnfc/.main }

no extras

 

[Rafal Galewski]

Scanning an NFC tag without a ndef record results in null pointer exception android

In android 4.1.1 - Scanning an NFC tag without a ndef record results in null pointer exception android

correct behaviour:
unformatted tags should be considered as such and not lead to an npe.


Worked correctly in 4.0.4.

 

[Erel]

I've tested it now with Android 4.1.2 and it runs fine. Try to run it in Release mode and see if you get any error. If you do then please post the logs.

 

[Rafal Galewski]

Thank You Erel,

When I use write TAG Mifare Classic with text data.
Data are correct reading but screen flickers.
When drawing shows the effect of light on the new.


When I use not formatted tag Mifare Classic , only want read UID - serial number tag in null pointer exception android.
I can't read UID serial number TAG.
This function correctly work on android 4.0.4 .
What is changes ?
When I use another software for example by NXP - correctly read UID .

PLease send to me on my email sample code working in You using UID and also using ndef recor.

Thank You for all.

Please help.

 

[Erel]

The NFC library only works with NDEF formatted tags. Other tags will not work.