I have a Widget that I reuse in my app, say the default "you have pressed the button this many times" Widget.
I have added an asynchronous saveData function to this Widget, which takes the int in the State and stores it (say in the Shared Preferences). The rationale is that I can store only once, instead of after every single change.
Now I use this Widget in an AlertDialog called by showDialog, and I use it again in a BottomSheet called by showModalBottomSheet. Additionally, I'd want to use it in a page of a PageView.
Is there a way to get the data to save when the Dialog or BottomSheet is Widget is disposed, or otherwise from the enclosing Widget (sheet/dialog)? I would rather not create two variations of my reused Widget just because it is wrapped in a different Widget, and pulling the State out of my reused Widget into the two parent Widgets also seems unnecessary.
I've been trying to use dispose and deactivate, but since I'm trying to use (a snapshot of) a Widget State variable, I couldn't do it: Doing asynchronous work and then calling super caused an error saying I failed to call super, and the other way around tells me I can't use the State after the Widget has been unmounted.
In the end, trying to intercept a dispose action was not a stable solution (esp. when using the State too).
I ended up giving my reused Widget an optional Key, and use a GlobalKey if I want to upload from outside the Widget (i.e. a submit button in the enclosing PageView page). In case of the BottomSheet, I've now simply set it to auto-save the value each time it changes if no key is present. It works for now, but is not ideal (and if anyone is aware of a better solution, I'm still interested :p).