Incorrect characters in transmitted data string

[lscott]

Very new to B4A but starting to make good progress.

I have a simple network program to transmitt a built up string.
The string includes some hex characters and some text characters.The character string I should be receiving at the PC server end is:
Hex 02D0000C01013030C086 but what I receive is: Hex 023F000C0101303030303F3F.
The vairables I have defined as CMD_LOGIN (0xD0),crcu(0hC0) and crcl (0x86) all get converted to 0x3f the ? character. Not sure if the accures in the building of the string or at time of transmitting the buffer.

Thanks for any ideals.
ScttH.

 

[Erel]

Use Log (or the debugger) to check the string value before it is sent.

The problem is that you are trying to send characters that are not valid in a string. chr(0) for example will break the string.
You should instead build the message as an array of bytes.

 

[lscott]

Array of Bytes

Thanks Erel for the info.

I built my command packet into an array of bytes. When I pass this to the Astream.write I get an exception message (java.lang.number format exception). I guess I am doing something fairly stupid. One other thing I was trying to send packet to a sub (SendData) but also had a number format issue.
Any direction would help.Thanks again

Sub btnSendMsg_Click


Dim packet(10) As Byte

Dim crcu As Byte:crcu = 0xc0
Dim crcl As Byte:crcl = 0x86
Dim STX As Byte:STX = 0x02
Dim CMD_LOGIN As Byte:CMD_LOGIN = 0xD0

' original string
'login_str = Chr(STX) & Chr(CMD_LOGIN) & Chr(0) & Chr(12) & Chr(1) & Chr(1) & "0000" & Chr(crcu) & Chr(crcl)
' build a packet array of bytes
packet(0) = STX
packet(1) = CMD_LOGIN
packet(2) = 0x00
packet(3) = 0x0C
packet(4) = 0x01
packet(5) = 0x01
packet(6) = "0000"
packet(7) = crcu
packet(8) = crcl

Dim bconv As ByteConverter
Dim buffer As Byte
If Socket1.Connected = True Then
Try
btnSendMsg.Text = buffer
TcpStreams.Write(packet)
Catch
Log("TcpStreams.Write Error")
Msgbox(LastException.Message, "Error connecting")
End Try
Else
Log("Connection lost")
Socket1.Close
Msgbox("Closing Socket", "Connection:")

End If

'SendData (packet)

End Sub

 

[Erel]

Please use [ code ] [ /code ] tags (without spaces) when posting code.

Which line raises this error? Run your code in Debug mode to find it.
I guess that the problem is with packet(6).