Android Question Communication problem Android 5.0, 5.1 POS Printer

[rscheel]

Dear, I currently have a POS printer connected via Bluetooth to my application, everything works fine with android 7 and 8 prints correctly without failures, the problem comes with Android 5, at the beginning it is good but when printing, close the application and return it to open , there comes a time where you can not find the printer connected by bluetooth or restarting the phone or closing the application completely reestablishes communication, until now the only way I have found is to unpair the connection and re-pair, that way it returns to have connection.


Has someone from the forum gone through this problem before?

Could you solve it?

This is the code that I use

Sub Activity_Create(FirstTime As Boolean)
    BtAdmin.Initialize("BlueTooth")
    BTConnection.Initialize("BTConnection")
    clTicket.Initialize
End Sub

Sub Activity_Pause (UserClosed As Boolean)
    oStream.Close
    BTConnection.Disconnect 'disable this if you like
End Sub

Sub InicioImpresion
    If BtAdmin.IsEnabled Then
        ProgressDialogShow2("Conectando Impresora", False)
        Dim PairedDevices As Map
        PairedDevices = BTConnection.GetPairedDevices
        Dim l As List
        Dim DeviceName, MacAddress As String
        l.Initialize
        For i = 0 To PairedDevices.Size - 1 'Check all devices
            l.Add(PairedDevices.GetKeyAt(i))
            DeviceName=PairedDevices.Getkeyat(i)
            MacAddress=PairedDevices.GetValueAt(i)
            Log(DeviceName & " -> " & MacAddress)
            If DeviceName.Contains(ModConn.NOM_BTH_CFG) Then 'Insert the BT-Name of the printer or use the MAC address
                Exit
            End If
        Next
        BTConnection.Connect(MacAddress)
        Sleep(2000)
    Else
        ProgressDialogShow2("Encendiendo Bluetooth...", False)
        BtAdmin.Enable
        Sleep(2000)
        ProgressDialogHide
        InicioImpresion
    End If
End Sub

Sub oStream_Error
    Log("oStream ERROR")
End Sub

Sub oStream_Terminated
    Log("oStream TERMINATED")
End Sub

Sub BTConnection_Connected (Success As Boolean)
    If Success Then
        oStream.Initialize(Null,BTConnection.OutputStream,"oStream")
        ProgressDialogHide
        CallSubDelayed(Me,"generatePrint")
    Else
        ProgressDialogHide
        ToastMessageShow("Impresora no encontrada", False)
    End If
End Sub

Sub generatePrint 'Imprime Ticket
    ProgressDialogShow2("Imprimiendo...", False)
    Dim bufferToPrint() As Byte = clTicket.getBytesForBitmap3("LogoM4.png",80)        'Third method: GS v --> adding white spaces

    Log( "Printing bitmap. buffer size is "&bufferToPrint.Length)
    Dim result As Boolean = oStream.Write( bufferToPrint )
   
    Printer.Initialize2(BTConnection.OutputStream,"windows-1252") 'important to print f.e. German/French chars
    PrintBuffer = Chr(27)&"t"&Chr(16)& CRLF & CRLF & _
                  "PATENTE     : "& PATENTE_PRT & CRLF & _
                  "CAMION      : "& COD_CAMION_PRT & CRLF & _
                  "TARA    : "& ModConn.nf.Format(TARA_PRT) &" Kg"& CRLF & _
                  "CARGA   : "& ModConn.nf.Format(CARGA_PRT) &" Kg"& CRLF & CRLF & _
                  "TOTAL   : "& ModConn.nf.Format(TOTAL_PRT) &" Kg"& CRLF & CRLF & _
                  "FECHA   : "& FECHA_PRT & CRLF & _
                  "DESPACHADOR : "& DESPACHADOR_PRT & CRLF & _
                  "N° GUÍA : "& NGUIA_PRT & CRLF & CRLF & _
                  "PRUEBA."& CRLF & CRLF & _
                  "TEXTO 1"& CRLF &  _
                  "TEXTO2."& CRLF & CRLF & _
                  "        PAGE" _
                  & CRLF & CRLF & CRLF & CRLF
    Printer.WriteLine(PrintBuffer)
    Printer.Flush
   
    Log( "Sent to printer! Success="&result &", "& Not(result))    'long message if sucess=False
    Printer.Close
    ProgressDialogHide
End Sub

 

[Erel]

It is probably not related to Android 5 but rather with the specific device that you are using. Bluetooth is far from being perfect on some devices.

Note that you can use the smart string literal. Your code will look much nicer.

 

[rscheel]

I tried it with several devices different brand with android 5 and the same thing happens, now I have removed the logo and apparently it has been fixed.