[Breaking Change] Introduce modal and page content decorators

[ulusoyca]

Summary

This PR refactors the modal decoration mechanism to separate the decoration of the modal barrier + content from the decoration of the content only. This also aligns it with the WoltModalType class methods, and resolves the existing issue with the decorator context (see comment).

Methods in WoltModalType class: decoratePageContent and decorateModal:

  /// Applies additional decorations to the modal page content.
  ///
  /// This method can be overridden to provide custom decorations such as safe area padding
  /// adjustments inside the modal page content. By default, it does not apply any decoration.
  /// See the [WoltBottomSheetType] for an example of how overriding this method could be used to
  /// fill the bottom safe area.
  Widget decoratePageContent(
    BuildContext context,
    Widget child,
    bool useSafeArea,
  ) =>
      child;

  /// Applies additional decorations to the modal content.
  ///
  /// This method can be overridden to provide custom decorations such as safe area padding
  /// adjustments around the modal including the barrier. By default, it applies safe area
  /// constraints if [useSafeArea] is `true`.
  Widget decorateModal(
    BuildContext context,
    Widget modal,
    bool useSafeArea,
  ) =>
      useSafeArea ? SafeArea(child: modal) : modal;

This PR introduces pageContentDecorator and modalDecorator:

  /// Applies additional decorations to the modal page content excluding the
  /// barrier. Use [modalDecorator] to apply decorations to the barrier and
  /// the content.
  Widget Function(Widget)? pageContentDecorator;

  /// Applies additional decorations to the modal including the barrier and the content.
  Widget Function(Widget)? modalDecorator;

Changes Made to Decorator Functions

Removed:

final Widget Function(Widget)? decorator;
Widget Function(Widget) get _decorator => widget.decorator ?? (widget) => Builder(builder: (_) => widget);

Added:

final Widget Function(Widget)? pageContentDecorator;
final Widget Function(Widget)? modalDecorator;
Widget Function(Widget) get _pageContentDecorator => widget.pageContentDecorator ?? (widget) => Builder(builder: (_) => widget);
Widget Function(Widget) get _modalDecorator => widget.modalDecorator ?? (widget) => Builder(builder: (_) => widget);

Benefits

The decorator function is split into pageContentDecorator and modalDecorator. This fixes the issue stated by @vishna in this comment. Previously, the decorator function only decorated the page modal content, leading to errors when the pageListBuilder created the pages because the decorator context was built after the pages are built.

Checklist

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• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• My PR includes tests for all changed/updated/fixed behaviors.
• All existing and new tests are passing.
• I updated/added relevant documentation (doc comments with ///).
• The analyzer (melos run analyze) does not report any problems on my PR.
• The package compiles with the minimum Flutter version stated in the pubspec.yaml

[TahaTesser]

LGTM

[TahaTesser]

We could get rid of the default builders and only apply when decorator builders are not null.

To save you time, i will push the commit with the suggestion. Please feel free to revert the commit if not agreed.

[TahaTesser]

Here is the applied commit 1406281

[ulusoyca]

@TahaTesser <3 you are amazing!