B4J Question Detect a Previous Instance of a running B4J App

aminoacid

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Is that any way to detect if a previous instance of a B4J App is running?

In VB6, you could do this with "If App.PreviousInstance then ......"

Just wondering if there is something similar in B4J, or a way to determine if the JAR file is already in execution.

Thanks!
 
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Dadaista

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B4J single instance

I wanted to limit my app to running as a single instance, in both Windows and Linux. Several solutions for this single instance problem have been posted, but usually do not include running in Linux. Erel made a few suggestions in one of his posts. One of these was to use an external file as a...
www.b4x.com

Post #4
 
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aminoacid

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Thanks for the pointer to the Post. Don't know how I missed that!
Great ideas!
I was hoping for a more elegant/simple solution but it looks like there isn't any. I think for now I'll go with the UDP socket technique.
Tx again.
 
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aminoacid

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I took rraswisak's code and wrote it as a Sub so it could be used in a manner similar to the VB6 " App.PreviousInstance" feature:

B4X: 
Sub AppPreviousInstance As Boolean
    Private xInstance As UDPSocket                     '<--- from jNetwork library
    Try
        xInstance.Initialize("",12340,0)             '<--- change the unique port as you want
        Return(False)
    Catch
        Return(True)
    End Try
End Sub

B4X: 
If AppPreviousInstance Then
        fx.Msgbox(MainForm, "Application already running !","Attention")
        ExitApplication
 End If

Thanks rraswisak!
 
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