showMongolMenu<T> function

Future<T?> showMongolMenu<T>({ required BuildContext context, required RelativeRect position, required List<MongolPopupMenuEntry<T>> items, T? initialValue, double? elevation, String? semanticLabel, ShapeBorder? shape, Color? color, bool useRootNavigator = false, })

Show a popup menu that contains the items at position.

items should be non-null and not empty.

If initialValue is specified then the first item with a matching value will be highlighted and the value of position gives the rectangle whose horizontal center will be aligned with the horizontal center of the highlighted item (when possible).

If initialValue is not specified then the right side of the menu will be aligned with the right side of the position rectangle.

In both cases, the menu position will be adjusted if necessary to fit on the screen.

Vertically, the menu is positioned so that it grows in the direction that has the most room. For example, if the position describes a rectangle on the top edge of the screen, then the top edge of the menu is aligned with the top edge of the position, and the menu grows to the bottom. If both edges of the position are equidistant from the opposite edge of the screen, then it grows down.

The positioning of the initialValue at the position is implemented by iterating over the items to find the first whose MongolPopupMenuEntry.represents method returns true for initialValue, and then summing the values of MongolPopupMenuEntry.width for all the preceding widgets in the list.

The elevation argument specifies the z-coordinate at which to place the menu. The elevation defaults to 8, the appropriate elevation for popup menus.

The context argument is used to look up the Navigator and Theme for the menu. It is only used when the method is called. Its corresponding widget can be safely removed from the tree before the popup menu is closed.

The useRootNavigator argument is used to determine whether to push the menu to the Navigator furthest from or nearest to the given context. It is false by default.

The semanticLabel argument is used by accessibility frameworks to announce screen transitions when the menu is opened and closed. If this label is not provided, it will default to MaterialLocalizations.popupMenuLabel.

See also:

• MongolPopupMenuItem, a popup menu entry for a single value.
• MongolPopupMenuDivider, a popup menu entry that is just a vertical line.
• MongolPopupMenuButton, which provides an IconButton that shows a menu by calling this method automatically.
• SemanticsConfiguration.namesRoute, for a description of edge triggered semantics.

Implementation

Future<T?> showMongolMenu<T>({
  required BuildContext context,
  required RelativeRect position,
  required List<MongolPopupMenuEntry<T>> items,
  T? initialValue,
  double? elevation,
  String? semanticLabel,
  ShapeBorder? shape,
  Color? color,
  bool useRootNavigator = false,
}) {
  assert(items.isNotEmpty);

  semanticLabel ??= MaterialLocalizations.of(context).popupMenuLabel;

  final NavigatorState navigator =
      Navigator.of(context, rootNavigator: useRootNavigator);
  return navigator.push(_PopupMenuRoute<T>(
    position: position,
    items: items,
    initialValue: initialValue,
    elevation: elevation,
    semanticLabel: semanticLabel,
    barrierLabel: MaterialLocalizations.of(context).modalBarrierDismissLabel,
    shape: shape,
    color: color,
    capturedThemes:
        InheritedTheme.capture(from: context, to: navigator.context),
  ));
}