Please try the example project a few days and let us know how it works for you...
It might be, your device tries to save system ressources and therefore terminates the service after a few days?
Which Android device and version are you using for your tests?
Additionally you might want to use
Taifun
Muchísimas gracias, gracias a tu información se me ocurrió revisar mi teléf. y pude ver que tenia muy poco espacio, por esta razón supongo que entro en modo de ahorro de recursos, libere espacio y volvió a funcionar.
Saludos.
hi, how can I enable and disable Notification listener?
For example,
If global.variable=0, then NotificationListener.Enabled=True
elseIf global.variable=1, then NotificationListener.Enabled=False
How can I achieve this?
only functionality is available, which is described in the documentation, everything else is not available.
To stop the service, just call method StartService for the user. The user then must disable notification access in the settings manually... see how it is done in the example app..
As the notification listener extension is open source, you are invited to investigate, if stopping the service programmatically is doable. If yes, you are invited to implement that functionality into the extension.
more information about how to create an extension see the App Inventor Extensions document however that will be more advanced and will require some Java skills...
Taifun
Trying to push the limits! Snippets, Tutorials and Extensions from Pura Vida Apps by 
Taifun.
I will try to update the extension codes in future so I can make & utilize more features. But, for now, somehow, I will find some shortcut ways and achieve this.
UPDATE: I am trying using the clock. I put the 'startService' block of notification listener within when.clock.timer. Now, I can enable or disable this block based on the value of the global.variable. But, I have not tested this yet.