This implements a MenuBar widget that can render a Material menu bar, and a MenuAnchor widget used to create a cascading menu in a region. The menus are drawn in the overlay, while the menu bar itself is in the regular widget tree. Keyboard traversal works between the two.
This implementation of the MenuBar uses MenuAnchor to create a cascading menu that contains widgets representing the menu items. These menu items can be any kind of widget, but are typically SubmenuButtons that host submenus, or MenuItemButtons that have shortcut hints (but don't actually activate the shortcuts) and don't host submenus.
Cascading menus can be created outside of a MenuBar by using a MenuAnchor. They can be either given a specific location to appear (a coordinate), or they can be located by the MenuAnchor region that wraps the control that opens them.
The developer may also create a MenuController to pass to the various menu primitives (MenuBar or MenuAnchor) to associate menus so that they can be traversed together and closed together. Creating a controller is not required.
* Update parameters to the `styleFrom` button methods.
* Updated the Flutter fix data to point to this PR.
* Updated handling of background color to better maintain backwards compatibility with previous API.
- - When I added notification of key events before processing them as text, it made it so that shortcut key bindings like the spacebar would prevent spaces from being inserted into text fields, which is obviously not desirable (and so that change was reverted). At the same time, we do want to make it possible to override key events so that they can do things like intercept a tab key or arrow keys that change the focus.
This PR changes the behavior of the Shortcuts widget so that if it has a shortcut defined, but no action is bound to the intent, then instead of responding that the key is "handled", it responds as if nothing handled it. This allows the engine to continue to process the key as text entry.
This PR includes:
- Modification of the callback type for key handlers to return a KeyEventResult instead of a bool, so that we can return more information (i.e. the extra state of "stop propagation").
- Modification of the ActionDispatcher.invokeAction contract to require that Action.isEnabled return true before calling it. It will now assert if the action isn't enabled when invokeAction is called. This is to allow optimization of the number of calls to isEnabled, since the shortcuts widget now wants to know if the action was enabled before deciding to either handle the key or to return ignored.
- Modification to ShortcutManager.handleKeypress to return KeyEventResult.ignored for keys which don't have an enabled action associated with them.
- Adds an attribute to DoNothingAction that allows it to mark a key as not handled, even though it does have an action associated with it. This will allow disabling of a shortcut for a subtree.
This fixes a problem where the character field of the RawKeyEvent was not being set at all for non-Android platforms.
I also updated the key maps, and corrected a problem with the Windows key map where the backquote character wasn't correctly mapped.
