How to modularize and customise pages?

The recent changes to page creation with the release of 0.9.0 renders the example discussed in #50 unfeasible:

class MainPage(ui.page):
    def __init__(self):
        super().__init__('/', dark=True)
        with self:
            ui.label('Hi!')

MainPage()

I have tried adapting the code (using PageBuilder) in the simple example, but failed to get it running as before.

from nicegui import ui
from nicegui.globals import page_builders
from nicegui.page import Page
from nicegui.page_builder import PageBuilder


class MainPage(Page):
    def __init__(self):
        super().__init__(dark=True)

        ui.label('Hi!')


async def page_builder() -> Page:
    return MainPage()


def index_page():
    builder = PageBuilder(shared=False, function=page_builder)
    page_builders.setdefault('/', builder)


index_page()

ui.run()

results in

    raise RuntimeError('cannot find parent view, view stack is empty')
RuntimeError: cannot find parent view, view stack is empty

I have just recently migrated a great chunks of previously justpy code to the above inheritance approach including additional element/group classes (such as header, layout, pagecontainer, …) and am now seeking ways to make it work, again.

@falkoschindler: could you please guide me here, again? Thanks!

This issue is possibly related to #85.

[hroemer]

@rodja many thanks for providing the discussion #99 and examples showing how to make use of ui.page. Apologies for my late reply, unfortunately I currently cannot devote much time on digging deeper here. I will get back to you once I wrapped my head around using this pattern.

[falkoschindler]

Another pattern might be to define the content in a class and do the routing in main.py:

class MainPage:
    def __init__(self):
        ui.label('Hi!')

@ui.page('/')
def main():
    MainPage()

---

Or define the page content in a function:

def main_page():
    ui.label('Hi!')

@ui.page('/')
def main():
    main_page()