B4R Question .AddListener doesn't seem to be working

[daveinhull]

Hi,

I've been trying to get .AddListener to work and I can't do it, probably something I'm doing or rather not doing.
I have a very simple bit of code.

Sub Process_Globals
    Public Serial1 As Serial
    Private encSWPin As Pin
End Sub

Sub Changed ()
    Log ("Listener Switch Changed")       
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("AppStart")
    encSWPin.Initialize (12,encSWPin.MODE_INPUT_PULLUP)
    encSWPin.AddListener("Changed")
end Sub

Any thoughts of what I might be doing wrong?

Many thanks

 

[Erel]

You haven't said what exactly isn't working.

Anyway, the event signature is wrong. It should be:

Sub Pin_StateChanged (State As Boolean)

Never write events signatures yourself. Let the IDE autocomplete then: Sub + space + Tab.

 

[daveinhull]

Thank Erel,

Ok, I changed the code to what you suggested, but it still doesn't seem to work, and what I mean is that nothing gets logged in the Pin_StateChanged sub.
Still not sure what I'm doing wrong.

B4X:

Sub Process_Globals
    Public Serial1 As Serial
    Private encSWPin As Pin
End Sub

Sub Pin_StateChanged (State as Boolean)
    Log ("Listener Switch Changed")       
End Sub

Private Sub AppStart
    Serial1.Initialize(115200)
    Log("AppStart")
    encSWPin.Initialize (12,encSWPin.MODE_INPUT_PULLUP)
    encSWPin.AddListener("Pin_StateChanged")
end Sub

 

[Erel]

Add a timer and check the pin state. My guess that the state doesn't change.

What is the pin connected to?

 

[daveinhull]

Hi Erel,

It's just connected to a push button which when I check the state, ie read the value, in a loop does work! The pin value changes. I could do it in a loop or use a timer, but wanted to get AddListener working.

I've also added a 4x4 keypad and used the keypad library to set it up, but that doesnt work either, I mean the key pressed routine never triggers.

[edit: pad.Initialize ("123A456B789C*0#D",Array As Byte(2,3,4,5), Array As Byte(6,7,8,9),"Pad_KeyPressed")]

Thanks
Dave

 

[Erel]

Have you created an endless loop somewhere in your program (maybe using Delay)? It will break many things.

 

[daveinhull]

Hi Erel and many thanks

Of course, how stupid I feel. I'd been thinking it was some kind of interrupt, but you've talked about interrupts being problematic so kept telling myself its not an interrupt so if its not an interrupt how does it work if I'm in a tight loop scanning things, der! Change my code to get rid of loops and use Listeners and Timers.

Many thanks there were so many other things not quite working as you said!

Thanks again
Dave

 

[Erel]

Never use Delay to control the program flow!

Resumable Subs (wait for / sleep) in server handlers

Resumable subs can only work when there is a message queue. By default, server handlers end when the Handle sub is completed. They do not create a message loop. If you want to wait for an event then you need to call StartMessageLoop and later StopMessageLoop. Example of handler that downloads...

www.b4x.com