fix: `NavigationBarDestination.disabled` has no visual effect

Description

Fixes #4029

Test Code

import flet as ft

def main(page: ft.Page):

    page.title = "NavigationBar Example"

    def handle_disable_change(e):
        page.navigation_bar.disabled = e.control.value
        page.update()

    def handle_adaptive_change(e):
        page.navigation_bar.adaptive = e.control.value
        page.update()

    page.navigation_bar = ft.NavigationBar(
        destinations=[
            ft.NavigationBarDestination(icon=ft.icons.EXPLORE, label="Explore"),
            ft.NavigationBarDestination(icon=ft.icons.COMMUTE, label="Commute"),
            ft.NavigationBarDestination(
                icon=ft.icons.BOOKMARK_BORDER,
                selected_icon=ft.icons.BOOKMARK,
                label="Explore",
            ),
        ],
    )
    page.add(
        ft.Switch("Disable", value=False, on_change=handle_disable_change),
        ft.Switch("Adaptive", value=False, on_change=handle_adaptive_change),
    )

ft.app(main)

Summary by Sourcery

Fix the visual effect of the disabled state in NavigationBarDestination and refactor the handling of adaptive and disabled states in navigation bar controls.

Bug Fixes:

Fix the issue where NavigationBarDestination.disabled had no visual effect by ensuring that the disabled state is properly handled in the navigation bar controls.

Enhancements:

Refactor the handling of adaptive and disabled states in navigation bar controls to improve code clarity and maintainability.

Reviewer's Guide by Sourcery

This pull request addresses an issue where the NavigationBarDestination.disabled property had no visual effect. The changes implement proper handling of disabled states for both NavigationBar and CupertinoNavigationBar, improve code organization, and enhance the overall functionality of navigation components.

Sequence Diagram

sequenceDiagram
    participant User
    participant NavigationBar
    participant Destination
    User->>NavigationBar: Tap destination
    NavigationBar->>NavigationBar: Check disabled state
    alt NavigationBar is not disabled
        NavigationBar->>Destination: Check destination disabled state
        alt Destination is not disabled
            Destination->>NavigationBar: Allow selection
            NavigationBar->>User: Update selected index
        else Destination is disabled
            Destination->>NavigationBar: Prevent selection
        end
    else NavigationBar is disabled
        NavigationBar->>User: No action
    end

File-Level Changes

Change	Details	Files
Implement proper handling of disabled state for NavigationBar and CupertinoNavigationBar	Add `disabled` check to `onDestinationSelected` callback Implement `destinationDisabled` flag for individual destinations Update `enabled` property of NavigationDestination based on `destinationDisabled` Modify `onTap` callback for CupertinoTabBar to respect disabled state	`packages/flet/lib/src/controls/navigation_bar.dart` `packages/flet/lib/src/controls/cupertino_navigation_bar.dart`
Refactor and improve code organization	Add `isAdaptive` getter to Control class Use `parseDuration` function for `animationDuration` Simplify `labelBehavior` assignment Remove redundant variable declarations	`packages/flet/lib/src/controls/navigation_bar.dart` `packages/flet/lib/src/models/control.dart`
Enhance flexibility and consistency of navigation components	Add support for `indicatorColor` as a fallback for `activeColor` in CupertinoTabBar Improve handling of adaptive property for individual destinations Update tooltip handling to allow null values	`packages/flet/lib/src/controls/navigation_bar.dart` `packages/flet/lib/src/controls/cupertino_navigation_bar.dart`

Tips and commands

#### Interacting with Sourcery - **Trigger a new review:** Comment `@sourcery-ai review` on the pull request. - **Continue discussions:** Reply directly to Sourcery's review comments. - **Generate a GitHub issue from a review comment:** Ask Sourcery to create an issue from a review comment by replying to it. #### Customizing Your Experience Access your [dashboard](https://app.sourcery.ai) to: - Enable or disable review features such as the Sourcery-generated pull request summary, the reviewer's guide, and others. - Change the review language. - Add, remove or edit custom review instructions. - Adjust other review settings. #### Getting Help - [Contact our support team](mailto:support@sourcery.ai) for questions or feedback. - Visit our [documentation](https://docs.sourcery.ai) for detailed guides and information. - Keep in touch with the Sourcery team by following us on [X/Twitter](https://x.com/SourceryAI), [LinkedIn](https://www.linkedin.com/company/sourcery-ai/) or [GitHub](https://github.com/sourcery-ai).

flet-dev / flet