B4J Code Snippet [BANano] Execute events when the internet is offline and or online

Hi there

The browser has a very nice way to detect whether its offline (internet off) and online (internet on), without one having to define a timer. The window object has an online and an offline status event. This can be useful when you want, when the internet goes off, log off a user etc etc.

So I have a class (in a library) that I initialize when my app starts. In the Initialize event I have added

'each time a connection changes, call the handleConnectionChange callback
    Dim e As BANanoEvent
    Dim ch As BANanoObject = BANano.CallBack(Me, "handleConnectionChange", Array(e))
    BANano.window.addEventListener("online", ch, True)
    BANano.window.addEventListener("offline", ch, True)

The handleConnectionChange callback will be fired whenever the internet is offline and online. This will call a sub called ConnectionChange in my project.

What I do is to pass a true (online) and a false (offline) result to another sub I need called

Private Sub handleConnectionChange(e As BANanoEvent)        'ignoreDeadCode
    Dim status As String = e.Type
    Dim bOn As Boolean
    Select Case status
    Case "online"
        bOn = True
    Case "offline"
        bOn = False        
    End Select
    If SubExists(EventHandler, "ConnectionChange") Then
        CallSub2(EventHandler, "ConnectionChange", bOn)
    End If
End Sub

I later ran my app, turned toggled my wifi state. works like a charm.

Private Sub ConnectionChange (status As Boolean)
    Log("ConnectionChange...")
    Log(status)
End Sub

#SharingTheGoodness

 

[alwaysbusy]

Note that this already automatically happens (for the main WebApp) by BANano in the Online() and Offline() events.

Sub BANano_OnLine()
    Log("online")
End Sub

Sub BANano_OffLine()
    Log("offline")
End Sub

Alwaysbusy

 

[Mashiane]

Great then, I guess I missed it as I wasn't aware.

 

[alwaysbusy]

Great then, I guess I missed it as I wasn't aware.

Your snippet could still be valuable if you want to catch the event outside of Main, e.g. in a library.

Alwaysbusy