headless_contracts#

Renderer contracts and slot overrides for Headless components.

This package defines the capability contracts (ISP) that components use to request renderers via HeadlessTheme.capability<T>().

Renderers implement these contracts to provide visual representation. Components never know the concrete renderer implementation.

Classes#

Class	Description
Decorate<C>	Decoration wrapper around the default — receives child and can wrap/modify.
Enhance<C>	Enhancement of the default — transforms context before calling defaults.
HeadlessRendererPolicy	Optional renderer policy for stricter contracts in debug/test.
RAutocompleteSelectedValuesCommands	Commands for rendering and interacting with selected values (multi-select).
RAutocompleteSelectedValuesOverrides	Per-instance overrides for selected values rendering (contract level).
RAutocompleteSelectedValuesRenderer	Renderer capability for selected values display (multi-select autocomplete).
RAutocompleteSelectedValuesRenderRequest
RButtonCallbacks	Callback references for button rendering (visual-only).
RButtonContentContext	Context for the button content slot.
RButtonIconContext	Context for the button icon slots.
RButtonMotionTokens	Motion tokens for button visual transitions.
RButtonOverrides	Per-instance override contract for Button components.
RButtonRenderer	Renderer capability for Button components.
RButtonRendererTokenMode	Optional renderer extension that declares resolved-tokens usage.
RButtonRenderRequest	Render request containing everything a button renderer needs.
RButtonResolvedTokens	Resolved visual tokens for button rendering.
RButtonSemantics	Semantic information for button accessibility.
RButtonSlots	Button slots for partial customization (Replace/Decorate/Enhance).
RButtonSpec	Button specification (static, from widget props).
RButtonSpinnerContext	Context for the button spinner slot.
RButtonState	Button interaction state.
RButtonSurfaceContext	Context for the button surface slot.
RButtonTokenResolver	Token resolver capability for Button components.
RCheckboxBoxContext	Context for checkbox box slot.
RCheckboxListTileCheckboxContext	Context for the checkbox indicator slot.
RCheckboxListTileMotionTokens	Motion tokens for checkbox list tile visual transitions.
RCheckboxListTileOverrides	Per-instance override contract for CheckboxListTile components.
RCheckboxListTileRenderer	Renderer capability for CheckboxListTile components.
RCheckboxListTileRenderRequest	Render request containing everything a checkbox list tile renderer needs.
RCheckboxListTileResolvedTokens	Resolved visual tokens for checkbox list tile rendering.
RCheckboxListTileSecondaryContext	Context for the secondary slot.
RCheckboxListTileSemantics	Semantic information for checkbox list tile accessibility.
RCheckboxListTileSlots	Slots for checkbox list tile parts (Replace/Decorate/Enhance).
RCheckboxListTileSpec	Checkbox list tile specification (static, from widget props).
RCheckboxListTileState	Checkbox list tile interaction state.
RCheckboxListTileTextContext	Context for title/subtitle slots.
RCheckboxListTileTileContext	Context for the list tile slot (wraps the default ListTile).
RCheckboxListTileTokenResolver	Token resolver capability for CheckboxListTile components.
RCheckboxMarkContext	Context for checkbox mark slot.
RCheckboxMotionTokens	Motion tokens for checkbox visual transitions.
RCheckboxOverrides	Per-instance override contract for Checkbox components.
RCheckboxPressOverlayContext	Context for checkbox press overlay slot.
RCheckboxRenderer	Renderer capability for Checkbox components.
RCheckboxRenderRequest	Render request containing everything a checkbox renderer needs.
RCheckboxResolvedTokens	Resolved visual tokens for checkbox rendering.
RCheckboxSemantics	Semantic information for checkbox accessibility.
RCheckboxSlots	Checkbox slots for partial customization (Replace/Decorate/Enhance).
RCheckboxSpec	Checkbox specification (static, from widget props).
RCheckboxState	Checkbox interaction state.
RCheckboxTokenResolver	Token resolver capability for Checkbox components.
RDropdownAnchorContext	Context for the anchor (trigger button) slot.
RDropdownButtonRenderer	Renderer capability for DropdownButton components.
RDropdownButtonSlots	Dropdown slots for partial customization (Replace/Decorate pattern).
RDropdownButtonSpec	Dropdown specification (static, from widget props).
RDropdownButtonState	Dropdown interaction state.
RDropdownChevronContext	Context for the chevron slot inside the trigger.
RDropdownCommands	Commands for dropdown interactions (internal component API).
RDropdownItemContentContext	Context for item content inside the menu item.
RDropdownItemContext	Context for an individual menu item slot.
RDropdownItemTokens	Resolved tokens for dropdown menu items.
RDropdownMenuContext	Context for the menu slot.
RDropdownMenuMotionTokens	Motion tokens for dropdown menu open/close.
RDropdownMenuRenderRequest	Render request for the dropdown menu (overlay).
RDropdownMenuSurfaceContext	Context for the menu surface (background/container) slot.
RDropdownMenuTokens	Resolved tokens for the dropdown menu surface.
RDropdownOverrides	Per-instance override contract for Dropdown components.
RDropdownRenderRequest	Render request containing everything a dropdown renderer needs.
RDropdownResolvedTokens	Resolved visual tokens for dropdown rendering.
RDropdownSemantics	Semantic information for dropdown accessibility.
RDropdownTokenResolver	Token resolver capability for Dropdown components.
RDropdownTriggerRenderRequest	Render request for the dropdown trigger (anchor).
RDropdownTriggerTokens	Resolved tokens for the dropdown trigger button.
RenderOverrides	Per-instance override bag for renderers and token resolvers.
RenderOverridesDebugTracker	Debug-only tracker for consumed override types.
Replace<C>	Full replacement of a slot — default is ignored (intentional).
RSwitchListTileMotionTokens	Motion tokens for switch list tile visual transitions.
RSwitchListTileOverrides	Per-instance override contract for SwitchListTile components.
RSwitchListTileRenderer	Renderer capability for SwitchListTile components.
RSwitchListTileRenderRequest	Render request containing everything a switch list tile renderer needs.
RSwitchListTileResolvedTokens	Resolved visual tokens for switch list tile rendering.
RSwitchListTileSecondaryContext	Context for the secondary slot.
RSwitchListTileSemantics	Semantic information for switch list tile accessibility.
RSwitchListTileSlots	Slots for switch list tile parts (Replace/Decorate/Enhance).
RSwitchListTileSpec	Switch list tile specification (static, from widget props).
RSwitchListTileState	Switch list tile interaction state.
RSwitchListTileSwitchContext	Context for the switch indicator slot.
RSwitchListTileTextContext	Context for title/subtitle slots.
RSwitchListTileTileContext	Context for the list tile slot (wraps the default ListTile).
RSwitchListTileTokenResolver	Token resolver capability for SwitchListTile components.
RSwitchMotionTokens	Motion tokens for switch visual transitions.
RSwitchOverrides	Per-instance override contract for Switch components.
RSwitchPressOverlayContext	Context for switch press overlay slot.
RSwitchRenderer	Renderer capability for Switch components.
RSwitchRenderRequest	Render request containing everything a switch renderer needs.
RSwitchResolvedTokens	Resolved visual tokens for switch rendering.
RSwitchSemantics	Semantic information for switch accessibility.
RSwitchSlots	Switch slots for partial customization (Replace/Decorate/Enhance).
RSwitchSpec	Switch specification (static, from widget props).
RSwitchState	Switch interaction state.
RSwitchThumbContext	Context for switch thumb slot.
RSwitchTokenResolver	Token resolver capability for Switch components.
RSwitchTrackContext	Context for switch track slot.
RTextFieldCommands	Commands for TextField renderer (v1).
RTextFieldOverrides	Per-instance overrides for TextField components (contract level).
RTextFieldRenderer	Renderer capability for TextField components.
RTextFieldRenderRequest	Render request containing everything a text field renderer needs.
RTextFieldResolvedTokens	Resolved visual tokens for TextField rendering.
RTextFieldSemantics	Semantic information for TextField accessibility (v1).
RTextFieldSlots	TextField slots for partial customization (Replace/Decorate pattern).
RTextFieldSpec	TextField specification (static, from widget props).
RTextFieldState	TextField interaction state.
RTextFieldTokenResolver	Token resolver capability for TextField components.
SafeDropdownChevronContext
SafeDropdownEmptyStateContext
SafeDropdownItemContentContext
SafeDropdownItemContext
SafeDropdownMenuSurfaceContext
SafeDropdownRenderer	Safe scaffold for full dropdown renderer customization.
SafeDropdownTriggerContext
SlotOverride<C>	Base class for slot overrides in renderer contracts.

Enums#

Enum	Description
RAutocompleteSelectedValuesPresentation	Presentation style for selected values (multi-select).
RButtonSize	Button size variants.
RButtonVariant	Button visual variants.
RCheckboxControlAffinity	Placement of the checkbox relative to text content.
RDropdownSize	Dropdown size variants.
RDropdownVariant	Dropdown visual variants.
ROverlayPhase	Overlay lifecycle phases.
RSwitchControlAffinity	Placement of the switch relative to text content.
RTextFieldOverlayVisibilityMode	Visibility mode for overlay elements in text fields (prefix, suffix, clear button).
RTextFieldVariant	TextField visual variants.

Functions#

Function	Description
mergeOverridesWithFallbacks	Merge multiple sugar layers into overrides with POLA priority.
mergeStyleIntoOverrides<TStyle, TOverride extends Object>	Merge a simple style object into RenderOverrides with POLA priority.

Typedefs#

Typedef
SafeDropdownChevronBuilder
SafeDropdownEmptyStateBuilder
SafeDropdownItemBuilder
SafeDropdownItemContentBuilder
SafeDropdownMenuSurfaceBuilder
SafeDropdownTriggerBuilder