B4J Question USB Serial Port

[ElliotHC]

Hi

I've just come to do a project where I need to read bytes coming in from the serial port, is there a simple example I can dissect?

Thanks

 

[ElliotHC]

If you're just sending text lines, then it's not hard to accumulate the incoming characters into a buffer and then dole them out when you have a complete line, eg:

Dim TextBuffer As String    'global serial port input buffer

Sub AStream_NewData (Buffer() As Byte)
 
    'add to buffer
    TextBuffer = TextBuffer & BytesToString(Buffer, 0, Buffer.Length, "UTF8")

    Dim EOLChar As String = Char(13)    'or 10 or 0 or whatever

    'dole out lines (if any)
    Do While True
        Dim EOLCharAt As Int = TextBuffer.IndexOf(EOLChar)
        If EOLCharAt = -1 Then
            Exit
        End If

        Dim TextLine As String = TextBuffer.SubString2(0, EOLCharAt)    'get next line
        TextBuffer = TextBuffer.SubString(EOLCharAt + 1)    'remove from buffer

        HandleTextLine(TextLine)
    Loop

End Sub

or if you prefer clarity over efficiency, you could change this bit:

'''Do While True
'''    Dim EOLCharAt As Int = TextBuffer.IndexOf(EOLChar)
'''    If EOLCharAt = -1 Then
'''        Exit
'''    End If

Do While TextBuffer.Contains(EOLChar)
    Dim EOLCharAt As Int = TextBuffer.IndexOf(EOLChar)    'should always find EOLChar

I'll try that first, thanks.

 

[Erel]

Check AsyncStreamsText.
https://www.b4x.com/android/forum/threads/27002/#content

 

[emexes]

Check AsyncStreamsText.

Spewin! I was wondering if the file text line functions might work, but figured they'd need a timer to convert from polled to event-driven, and apparently this app is needed tomorrow, so I didn't pursue that angle.

Now me with my crystal ball is looking a bit of a dunce again, but... all's well that ends well

 

[Erel]

BTW, AsyncStreamsText is quite an old class. If I would have written it now then I would have used B4XBytesBuilder from B4XCollections instead of StringBuilder.