fluffychat/lib/utils/contextual_actions.dart

import 'package:flutter/material.dart';

class ContextualActions extends InheritedWidget {
  final ContextualActionState _state = ContextualActionState();

  ContextualActions({Key? key, required Widget child})
      : super(key: key, child: child);

  static ContextualActions of(BuildContext context) {
    final ContextualActions? result =
        context.dependOnInheritedWidgetOfExactType<ContextualActions>();
    assert(result != null, 'No ContextualActions found in context');
    return result!;
  }

  Set<ContextualAction> get actions => _state.actions;
  set actions(Set<ContextualAction> actions) => _state.actions = actions;

  List<Widget> buildAppBar() => _state.buildAppBar();
  List<Widget> buildContextMenu(BuildContext context) =>
      _state.buildContextMenu(context);

  @override
  bool updateShouldNotify(covariant ContextualActions oldWidget) =>
      _state != oldWidget._state;
}

class ContextualActionState {
  /// the currently set [ContextualActions]
  ///
  /// use [replace] instead of `=` operator
  Set<ContextualAction> actions = {};
  Set<ContextualAction> contextMenuOnly = {};

  /// unregisters all present actions and adds riven [newActions]
  void replace(Iterable<ContextualAction> newActions) {
    actions.removeWhere((element) => true);
    actions.addAll(newActions);
  }

  /// buildseach item of [actions] as [IconButton] for use in AppBar
  List<Widget> buildAppBar() {
    return actions
        .map(
          (action) => IconButton(
            icon: action.icon,
            tooltip: action.label,
            onPressed: action.action,
          ),
        )
        .toList();
  }

  /// builds each item of [actions] as [ListTile] for use in a [ContextMenuArea]
  List<Widget> buildContextMenu(BuildContext context) {
    return actions
        .map(
          (action) => ListTile(
            leading: action.icon,
            title: Text(action.label),
            onTap: () {
              Navigator.of(context).pop();
              action.action.call();
            },
          ),
        )
        .toList();
  }
}

class ContextualAction {
  final VoidCallback action;
  final Widget icon;
  final String label;

  const ContextualAction(
      {required this.action, required this.icon, required this.label});
}