feat: BottomAppBar.border_radius property

[ndonkoHenri]

Fix #4322

Example Code

import flet as ft


def main(page: ft.Page):
    page.vertical_alignment = ft.MainAxisAlignment.CENTER
    page.horizontal_alignment = ft.CrossAxisAlignment.CENTER

    page.bottom_appbar = ft.BottomAppBar(
        border_radius=ft.BorderRadius.all(20),
        bgcolor=ft.Colors.BLUE,
        content=ft.Row(
            controls=[
                ft.IconButton(icon=ft.Icons.MENU, icon_color=ft.Colors.WHITE),
                ft.Container(expand=True),
                ft.IconButton(icon=ft.Icons.SEARCH, icon_color=ft.Colors.WHITE),
                ft.IconButton(icon=ft.Icons.FAVORITE, icon_color=ft.Colors.WHITE),
            ]
        ),
    )

    page.add(ft.Text("Content goes here..."))


ft.run(main)

Summary by Sourcery

Enable custom border radius on BottomAppBar by introducing a new property, updating rendering logic in both Python and Dart components, and enhancing documentation and default value descriptions.

New Features:

• Add border_radius property to BottomAppBar with automatic clipping support

Enhancements:

• Standardize default fallback descriptions for BottomAppBar properties (bgcolor, shadow_color, padding, clip_behavior, shape, elevation)
• Adjust clip behavior logic in Dart renderer to respect border_radius settings
• Refine FloatingActionButton docstrings to use consistent error messages for negative values

Documentation:

• Add a custom border radius example and image to BottomAppBar documentation

[Copilot]

Pull Request Overview

This PR adds a border_radius property to the BottomAppBar control, allowing developers to customize the corner rounding of the bottom app bar. The implementation also updates documentation formatting and error messages for consistency.

• Added border_radius property to BottomAppBar with corresponding Python and Dart implementations
• Updated clip_behavior to automatically default to ANTI_ALIAS when border radius is applied
• Improved documentation strings across multiple properties for clarity and consistency

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
sdk/python/packages/flet/src/flet/controls/material/bottom_app_bar.py	Added border_radius property, updated property documentation, and modified clip_behavior default behavior
packages/flet/lib/src/controls/bottom_app_bar.dart	Implemented border radius rendering using ClipRRect wrapper with automatic clip behavior handling
sdk/python/examples/controls/bottom_app_bar/border_radius.py	Added example demonstrating the new border_radius property usage
sdk/python/packages/flet/docs/controls/bottomappbar.md	Added documentation section for custom border radius feature
sdk/python/packages/flet/src/flet/controls/material/floating_action_button.py	Standardized error message formatting in documentation

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

Missing space after colon. Should be 'ValueError: If' not 'ValueError:If'.

Suggested change

	ValueError:If it is less than `0`.
	ValueError: If it is less than `0`.

[FeodorFitsner]

Fix it?

[sourcery-ai]

We've reviewed this pull request using the Sourcery rules engine

[cloudflare-workers-and-pages]

Deploying flet-docs with    Cloudflare Pages

Latest commit:	f6c4784
Status:	✅  Deploy successful!
Preview URL:	https://13a5f35a.flet-docs.pages.dev
Branch Preview URL:	https://bottom-appbar-radius.flet-docs.pages.dev

View logs

[FeodorFitsner]

Example screenshot must be generated with integration test. See example here: packages/flet/integration_tests/examples/material/test_bottom_app_bar.py
You will probably need to set window size like, for example, in this test: packages/flet/integration_tests/examples/material/test_bottom_sheet.py