comunicmobile/lib/ui/widgets/navbar_widget.dart

import 'package:comunic/utils/intl_utils.dart';
import 'package:flutter/material.dart';

/// Navigation bar widget
///
/// @author Pierre HUBERT

typedef OnSelectMenuAction = void Function(BarCallbackActions);

/// Callback actions
enum BarCallbackActions {
  OPEN_CONVERSATIONS,
  OPEN_NEWEST_POSTS,
  OPEN_FRIENDS,
  OPEN_MY_PAGE,
  OPEN_APP_SETTINGS,
  NONE,
  ACTION_LOGOUT
}

const _PrimaryColor = Colors.blue;
const _SecondaryColor = Colors.white;

/// Menu item information
class _MenuItem {
  final String label;
  final Widget icon;
  final BarCallbackActions action;
  final bool isMenu;

  const _MenuItem({
    @required this.label,
    @required this.icon,
    @required this.action,
    this.isMenu = false,
  })  : assert(label != null),
        assert(icon != null || isMenu),
        assert(action != null),
        assert(isMenu != null);
}

/// Item of action menu
class _ActionMenuItem {
  final String label;
  final BarCallbackActions action;

  const _ActionMenuItem({@required this.label, @required this.action})
      : assert(label != null),
        assert(action != null);
}

/// List of menu items to show
final _menuItems = <_MenuItem>[
  _MenuItem(
      label: tr("Conversations"),
      icon: Icon(Icons.comment),
      action: BarCallbackActions.OPEN_CONVERSATIONS),
  _MenuItem(
      label: tr("Newest"),
      icon: Icon(Icons.refresh),
      action: BarCallbackActions.OPEN_NEWEST_POSTS),
  _MenuItem(
      label: tr("Friends"),
      icon: Icon(Icons.group),
      action: BarCallbackActions.OPEN_FRIENDS),
  _MenuItem(
      label: tr("Menu"),
      icon: Icon(Icons.more_vert),
      isMenu: true,
      action: BarCallbackActions.NONE)
];

/// List of menu actions items
final _menuActionsItem = <_ActionMenuItem>[
  _ActionMenuItem(
      label: tr("My Page"), action: BarCallbackActions.OPEN_MY_PAGE),
  _ActionMenuItem(
      label: tr("App settings"), action: BarCallbackActions.OPEN_APP_SETTINGS),
  _ActionMenuItem(
      label: tr("Sign out"), action: BarCallbackActions.ACTION_LOGOUT),
];

/// Public widget
class ComunicAppBar extends StatelessWidget implements PreferredSizeWidget {
  final OnSelectMenuAction onTap;
  final BarCallbackActions selectedAction;

  const ComunicAppBar(
      {Key key, @required this.onTap, @required this.selectedAction})
      : assert(onTap != null),
        super(key: key);

  @override
  Widget build(BuildContext context) {
    return Material(
      color: Colors.blue,
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: List.generate(
          _menuItems.length,
          (i) => _MenuItemWidget(
            item: _menuItems[i],
            onTap: onTap,
            isSelected: _menuItems[i].action == selectedAction,
          ),
        ),
      ),
    );
  }

  @override
  Size get preferredSize => Size.fromHeight(35);
}

/// The [Widget] part of a menu item
class _MenuItemWidget extends StatelessWidget {
  final _MenuItem item;
  final OnSelectMenuAction onTap;
  final bool isSelected;

  const _MenuItemWidget(
      {Key key,
      @required this.item,
      @required this.onTap,
      @required this.isSelected})
      : assert(item != null),
        assert(onTap != null),
        assert(isSelected != null),
        super(key: key);

  @override
  Widget build(BuildContext context) {
    assert(debugCheckHasMaterial(context));

    return Expanded(
      child: Material(
        color: isSelected ? _SecondaryColor : _PrimaryColor,
        child: !item.isMenu
            ? InkWell(
                child: _buildIconContainer(),
                onTap: () => onTap(item.action),
              )
            : _buildContextMenuPopupButton(),
      ),
    );
  }

  Widget _buildIconContainer() {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        IconTheme(
          data: IconThemeData(
              color: isSelected ? _PrimaryColor : _SecondaryColor),
          child: item.icon,
        )
      ],
    );
  }

  // Build context menu
  Widget _buildContextMenuPopupButton() {
    return PopupMenuButton<BarCallbackActions>(
      child: _buildIconContainer(),
      itemBuilder: (i) => _menuActionsItem
          .map((f) => PopupMenuItem(
                child: Text(f.label),
                value: f.action,
              ))
          .toList(),
      onSelected: onTap,
    );
  }
}