Module tab_navigation

This module provides a framework for handling linear tab-key navigation in Bevy applications.

The rules of tabbing are derived from the HTML specification, and are as follows:

• An index >= 0 means that the entity is tabbable via sequential navigation. The order of tabbing is determined by the index, with lower indices being tabbed first. If two entities have the same index, then the order is determined by the order of the entities in the ECS hierarchy (as determined by Parent/Child).
• An index < 0 means that the entity is not focusable via sequential navigation, but can still be focused via direct selection.

Tabbable entities must be descendants of a TabGroup entity, which is a component that marks a tree of entities as containing tabbable elements. The order of tab groups is determined by the TabGroup::order field, with lower orders being tabbed first. Modal tab groups are used for ui elements that should only tab within themselves, such as modal dialog boxes.

To enable automatic tabbing, add the TabNavigationPlugin and InputDispatchPlugin to your app. This will install a keyboard event observer on the primary window which automatically handles tab navigation for you.

Alternatively, if you want to have more control over tab navigation, or are using an input-action-mapping framework, you can use the [TabNavigation] system parameter directly instead. This object can be injected into your systems, and provides a navigate method which can be used to navigate between focusable entities.

Structs

TabGroup

A component used to mark a tree of entities as containing tabbable elements.

TabIndex

A component which indicates that an entity wants to participate in tab navigation.

TabNavigationPlugin

Plugin for navigating between focusable entities using keyboard input.

Enums

NavAction

A navigation action that users might take to navigate your user interface in a cyclic fashion.

TabNavigationError

An error that can occur during tab navigation.

Functions

handle_tab_navigation

Observer function which handles tab navigation.