Android Question Error when print bluetooth with AsyncStreams

[Jose Cuevas]

Hi, I'm printing an invoice using a BT Printer, everything works fine, but when I turn off the printer, and try to print, triggers the AStreams_Error Event with this errors:

java.io.IOException: socket closed
java.io.IOException: read failed, socket might closed or timeout, read ret: -1

That's ok, that is how I know the printer is not available, but when I turn on the printer, I have the same errors, it's like is not reconnecting again.

Thanks in advance for your help.

 

[DonManfred]

but when I turn on the printer, I have the same errors, it's like is not reconnecting again.

a reconnection is not made automatically. Do you call connect again?

 

[Jose Cuevas]

Hi DonManfred, that's correct, This is the code:

Sub Process_Globals

    Dim BtAdmin As BluetoothAdmin
    Dim BTConnection As Serial
    Dim lMacAddress As String = "00:17:AC:01:46:A9"
    Dim Printer As AsyncStreams

End Sub

Sub Globals

End Sub

Sub Activity_Create(FirstTime As Boolean)

    Activity.LoadLayout("Main")
    
    If FirstTime Then
        ConnectPrinter
    End If

End Sub

Sub btnPrint_Click
    
    Try   

        Dim sText As String = "This is a test, This is a test, This is a test, This is a test" & CRLF & "This is a test, This is a test, This is a test" & CRLF
        
        BTSend(sText & CRLF & CRLF)
                
    Catch
        Log(LastException)
    End Try

End Sub

Sub BTSend(pText As String)

    Dim lBuffer() As Byte
    lBuffer=pText.GetBytes("UTF8")
    Printer.Write2(lBuffer,0,lBuffer.Length)
    
End Sub

Sub Printer_Connected (Success As Boolean)

    If Success Then
        Printer.Initialize(BTConnection.InputStream, BTConnection.OutputStream, "AStreams")
    Else
        Log("Printer_Connected Error: " & LastException.Message)
    End If

End Sub

Sub AStreams_Error
        
    Log("AStreams_Error:" & LastException.Message)

    If LastException.Message.Contains("bt socket close") Then
        ConnectPrinter
    Else
        Msgbox2("Unable to connect to printer","Error","OK","","", Null)
    End If
    
End Sub

Sub AStreams_Terminated
    Log("AStreams_Terminated")
End Sub

Sub ConnectPrinter
    
    BtAdmin.Initialize("BlueTooth")
    BTConnection.Initialize("Printer")
    
    Sleep(1000)
    
    BTConnection.Disconnect
    BTConnection.Connect(lMacAddress)
    
End Sub

 

[Jose Cuevas]

When I turn off the printer, triggers the AStream_Error and Printer_Connected event at the same time:

AStreams_Error:java.io.IOException: bt socket closed, read return: -1
Printer_Connected Error: java.io.IOException: read failed, socket might closed or timeout, read ret: -1

So, I try to reconnect at the AStreams_Error event, executing the ConnectPrinter Sub.

Regards.

 

[Jose Cuevas]

The same thing if I send the print when the printer is off, then turn on the printer, send the print again, and shows the same 2 errors, I have to close de App,
so that I can print again.

 

[Erel]

Don't call BTConnection.Disconnect after you initialize BTConnection.
Your code almost immediately tries to reconnect. You need to retry until you are able to connect.

 

[Jose Cuevas]

Hi Erel, I just delete the line BTConnection.Disconnect, but now throw the AStreams_Error event, with this error: java.io.IOException: Broken pipe

If I exit from de App using Activity.Finish and execute the App again, shows the same error: java.io.IOException: Broken pipe
I have to force stop the App, in order to the printer works again.

Is like the app take over the printer, because the printer is disabled for other devices, until I force the App to stop, other devices can already print on that printer.

I have tried with 2 different printers and I have the same result.

Regards,

 

[f0raster0]

have you tried this example:
https://www.b4x.com/android/forum/t...receipt-printer-with-matching-codepage.76831/

 

[Jose Cuevas]

Hi f0raster0 thanks, but this is how I currently print in my Apps, but I read in this post https://www.b4x.com/android/forum/threads/sd-bt-printer-bluetooth.85750/#content that the TextWriter could freeze the App, and that's what I'm experimenting with my Apps, so I wanted to avoid this with AsyncStreams method or maybe I misunderstood.

 

[Erel]

I don't see where your code tries to reconnect to the printer.

I recommend you to avoid trying to maintain an active connection with the printer. When you want to print, connect to the printer, send the data and close the connection.

 

[Jose Cuevas]

Thanks Erel, I wrote a new code (Connect -> Print -> Disconnect) now works like a charm.

This is the final code:

Sub Process_Globals

    Dim BTConnection As Serial
    Dim BTPrinter As AsyncStreams

    Dim MACAddress As String = "00:17:AC:01:46:A9"
    
End Sub

Sub Globals

End Sub

Sub Activity_Create(FirstTime As Boolean)
    
    Activity.LoadLayout("Main")
    
    If FirstTime Then
        BTConnection.Initialize("Printer")
    End If

End Sub

Sub btnPrint_Click
    
    StartPrint       
    
End Sub

Sub StartPrint

    ProgressDialogShow("Printing")

    Try
        BTConnection.Connect(MACAddress)

    Catch
        Msgbox("Unable to connect to printer","Printer Error")
        BTPrinter.Close
        BTConnection.Disconnect
    End Try
    
End Sub

Sub Printer_Connected (Success As Boolean)
    
    Try
        If Success Then
            BTPrinter.Initialize(BTConnection.InputStream, BTConnection.OutputStream, "AStreams")
        
            BTPrint("This is a test, this is a test" & CRLF & _
                    "This is a test, this is a test" & CRLF & _
                    "This Is a test, this Is a test" & CRLF & _
                    "This is a test, this is a test" & CRLF & _
                    "This Is a test, this Is a test" & CRLF & CRLF)
                    
            ProgressDialogHide
            
            BTPrinter.Close
            BTConnection.Disconnect
        Else
            ProgressDialogHide

            If Msgbox2("Unable to connect to printer", "Printer Error","Try Again","Cancel","",Null) = DialogResponse.POSITIVE Then
                BTConnection.Disconnect
                StartPrint
            Else
                BTConnection.Disconnect
            End If
        End If
    
    Catch
        Log(LastException)
    End Try

End Sub


Sub BTPrint(pText As String)

    Dim lBuffer() As Byte
    lBuffer = pText.GetBytes("UTF8")
    BTPrinter.Write2(lBuffer, 0, lBuffer.Length)
    
End Sub

Sub AStreams_Error
    Log("AStreams_Error:" & LastException.Message)
End Sub

Sub AStreams_Terminated
    Log("AStreams_Terminated")
End Sub

Regards.