how can I change data state

[engamir1]

how can I change state through app pages and make listeners to data changes?
is that by
page. update()

[iron3oxide]

In flet itself, each control has its own state. To create a listener/handler, define a function/method that takes at least one argument (commonly named e because it represents the event that is being received). Each flet control should have a set of properties that hold functions that are automatically called when the data of that control changes or some other interaction happens. A common example might be the on_change property. You can set that property to your listener/handler when you create the control or afterwards.