flutter, what is the right way to change appbar leading icon at app theme level?

Question

flutter, what is the right way to change appbar leading icon at app theme level? so I no need to change on each screen?

I know the following code work for specific screen...

AppBar(
  title: Text("Hello Appbar"),
  leading: Icon(
    Icons.arrow_back,
  ),
);

but I don't want to do it on each screen, Just checking here if I can set it at app theme level so it is same for all screen...

I referred flutter documentation for appbar, but it was not much helpful.

Answer 1

You can do something like this

import 'package:flutter/material.dart';

AppBar MyAppBar({Widget title, Widget leading}) {
  return AppBar(
    title: title,
    leading: leading,
  );
}

Answer 2

Use IconButton to change the leading icon.

 AppBar(
  title: Text("Hello Appbar"),
  leading: IconButton(
   onPressed: () {},
   icon: Icon(Icons.arrow_back)
  ),
);