How to refresh a page after back button pressed

If at your list page, you create function let say retrieveData() to read list of the data then call it inside initState, if you're using pushNamed route, the simple solution would be

Navigator.pushNamed(context, '/adddatapage').whenComplete(retrieveData());

If you're using push route,

Navigator.of(context).push(new MaterialPageRoute(builder: (context) => AddPage())).whenComplete(retrieveData);

That should be enough. No need to additional code on the add page. This will be works if user press back button also, again, without additional code in the add page.

I passed a callback method into the "add" page as a Navigator route argument. The callback is a method in my list page. The "add" page executes the callback when exiting. The callback method then simply refreshes the data and calls setState to refresh the screen.

My architecture is using Provider and viewmodels, but it should be straight-forward in a standard app as well.

Adding a option to @ian 's answer

Navigator.of(context)
  .push(new MaterialPageRoute<String>(...))
  .then((value) => setState(() => {}));

This worked for me. This will rebuild whenever page is loaded.

The Navigator.push method returns a future of the generic type of the Route:

Navigator.of(context)
  .push(new MaterialPageRoute<String>(...))
  .then((String value) {
    print(value);
  });

And inside the new route, when you have the value you need:

Navigator.of(context).pop('String');