PlatformMenuDelegate class Null safety

An abstract delegate class that can be used to set WidgetsBinding.platformMenuDelegate to provide for managing platform menus.

This can be subclassed to provide a different menu plugin than the default system-provided plugin for managing PlatformMenuBar menus.

The setMenus method allows for setting of the menu hierarchy when the PlatformMenuBar menu hierarchy changes.

This delegate doesn't handle the results of clicking on a menu item, which is left to the implementor of subclasses of PlatformMenuDelegate to handle for their implementation.

This delegate typically knows how to serialize a PlatformMenu hierarchy, send it over a channel, and register for calls from the channel when a menu is invoked or a submenu is opened or closed.

See DefaultPlatformMenuDelegate for an example of implementing one of these.

See also:

  • PlatformMenuBar, the widget that adds a platform menu bar to an application, and uses setMenus to send the menus to the platform.
  • PlatformMenu, the class that describes a menu item with children that appear in a cascading menu.
  • PlatformMenuItem, the class that describes the leaves of a menu hierarchy.


A const constructor so that subclasses can have const constructors.


hashCode int
The hash code for this object. [...]
read-only, inherited
runtimeType Type
A representation of the runtime type of the object.
read-only, inherited


clearMenus() → void
Clears any existing platform-rendered menus and leaves the application with no menus. [...]
debugLockDelegate(BuildContext context) bool
This is called by PlatformMenuBar when it is initialized, to be sure that only one is active at a time. [...]
debugUnlockDelegate(BuildContext context) bool
This is called by PlatformMenuBar when it is disposed, so that another one can take over. [...]
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed. [...]
setMenus(List<MenuItem> topLevelMenus) → void
Sets the entire menu hierarchy for a platform-rendered menu bar. [...]
toString() String
A string representation of this object. [...]


operator ==(Object other) bool
The equality operator. [...]