Android Question Replace � as ""

[petr4ppc]

Dear friends, please help,

I have string where I have this: 123x456�������������������������������������

How to replace please � as "" (nothing)

Best regards
p4ppc

 

[Erel]

It looks like an encoding problem. Where does this string come from?

 

[petr4ppc]

Dear Erel,

this string comes if I receive UDP

    Dim msg2 As String
    msg2 = BytesToString(Result,0, Result.Length,"UTF8")

msg2=123x456�������������������������������������...............
Lenght of string is 8192

Best regards
p4ppc

 

[Erel]

Where does result come from? Is this the PacketArrived event? Post the code...

 

[petr4ppc]

Yes Erel, here from service:

Dim UDPSocket1 As UDPSocket

End Sub

Sub Service_Create
 UDPSocket1.Initialize("UDP", 5000, 8192)
 Dim server2 As ServerSocket
End Sub

Sub Service_Start (StartingIntent As Intent)

End Sub

Sub Service_Destroy

End Sub

Sub UDP_PacketArrived (Packet As UDPPacket)
        Dim msgudp As String
    msgudp=""
    msgudp = BytesToString(Packet.data,0, 4,"UTF8")
    CallSubDelayed2(Main, "receiveudp", Packet.data)
End Sub

 

[Erel]

  Dim msgudp As String
    msgudp=""
    msgudp = BytesToString(Packet.data,0, 4,"UTF8")

Equivalent to:

Dim msgudp As String = BytesToString(Packet.data,0, 4,"UTF8")

The length will be maximum 4 characters.

The correct code assuming that it is a text message encoded with UTF8:

Dim msgudp As String = BytesToString(Packet.Data, Packet.Offset, Packet.Length, "UTF8")

 

[petr4ppc]

Thank you erel and it is possible to do correction with delete � in the string? How can I do it? Please..

 

[DonManfred]

i would check if there are 0-bytes in the data and cut the dataarray at the first 0 byte.

Lenght of string is 8192

filles with 0-bytes after the containing string?
Are you getting Binary Data and just want to convert them to a string?

I would use https://www.b4x.com/android/forum/pages/results/?query=byteconverter library and convert the data to a hex string and then POST this hex string. It may give an idea of what is inside....

 

[petr4ppc]

DonManfred - thank you for your answer, I go to read byteconverter library

best regards
p4ppc

 

[agraham]

Shouldn't you be passing msgudp to CallSubDelayed and not Packet.data?

 

[emexes]

I have string where I have this: 123x456�������������������������������������

How to replace please � as "" (nothing)

Best regards
p4ppc

Assuming that it is indeed a fixed-length string padded with NULs (ie ASCII 0x00), then

Dim msg2 As String
msg2 = BytesToString(Result, 0, Result.Length, "UTF8").Replace(Chr(0), "")

If that doesn't work, then perhaps the �s are some other character (0x7F aka DEL is another common non-printable padding), so check using:

Dim msg2 As String
msg2 = BytesToString(Result, 0, Result.Length, "UTF8")
Log("Last character is Chr(" & Asc(msg2.CharAt(msg2.Length - 1)) & ")")
Log("Last byte is " & Result(Result.Length - 1))

I would expect the same number in both those Logs, but... NUL is sometimes handled differently to other characters, particularly eg as an end-of-string marker, so I wouldn't like to stake my life on that expectation ;-)

 

[emexes]

Just in case you miss that subtle addition at first glance, that's:

msg2 = BytesToString(Result, 0, Result.Length,"UTF8").Replace(Chr(0), "")

 

[petr4ppc]

Thank you very much friends, for your help and examples,

I have tried before sleeping Erels solution and its absolute 100 percent OK.

Best regards
p4ppc

 

[emexes]

it's absolute 100 percent OK

Absolute 100 percent?!? Nothing warms my heart more than a bit of unbridled optimism.

But if things do happen to go awry, and you find that msgupd.Length is unexpectedly shorter than Packet.Length... remember that bytes with the high bit set usually represent a multibyte UTF-8 character, eg 2 bytes = 1 character.

But if you're just sending plain 7-bit ASCII, or actual UTF-8... then perhaps 100% is correct.