Navigator.pop() callback?

Question

Is there a callback function or a way to know that Navigator.of(context).pop()'s animation back into the previous screen has finished? currently Im using await Future.delayed(Duration(milliseconds: 500)); to accomplish this. Is there a better way?

Im using it for showModalBottomSheet(useRootNavigator: true) then Navigator.pop() to close the bottom sheet, then push a new route.

code:

Navigator.of(context).pop();
await Future.delayed(Duration(milliseconds: 500));
Navigator.of(context).push(...) // push new screen

Answer 1

Pushing a route already maintains a Future that completes when a pop occurs. This means you can do this:

Navigator.of(context).pushNamed('/someRoute').then((completion){
    //do something
});

The parameter named completion could also be any data you want to retrieve from the screen you are showing. For example let's say I have a group chat and I want to add a user to it. To do that I want to show a screen that allows me to pick a user then pass that user back to the previous screen.

Navigator.of(context).pushNamed('/InviteToChatScreen').then((object) {
    if (object != null) {
        var user = object as User;
        //add them to the chat
    }
});