Updated with default icons

routes.py

import flet
from flet import AppBar
from flet import ElevatedButton
from flet import Page
from flet import Text
from flet import View


class FirstPage(View):
    def __init__(self, page):
        super().__init__(
            '/',
            [
                AppBar(title=Text("Flet app")),
                ElevatedButton("Go to settings", on_click=self.open_settings),
            ]
        )

        self.page = page

    def open_settings(self, e):
        self.page.views.append(
            View(
                "/settings",
                [
                    AppBar(title=Text("Settings")),
                    Text("Settings"),
                ],
            )
        )
        self.page.update()

    def pop_settings(self, e):
        self.page.views.pop()
        self.page.update()


def default_view_pop(view):
    page = view.page
    page.views.pop()
    page.update()


def main(page: Page):
    page.title = "Routes Example"
    page.views.clear()
    page.views.append(FirstPage(page))
    page.on_view_pop = default_view_pop
    page.update()


flet.app(target=main)