import { FocusKeyManager, FocusOrigin } from '@angular/cdk/a11y';
import { OnDestroy, QueryList } from '@angular/core';
import { Subject } from 'rxjs';
import { TabbableListItemDirective } from './tabbable-list-item.directive';
import * as i0 from "@angular/core";
export declare class TabbableListService implements OnDestroy {
    /** Indicate is this is being using on a hierarchichal set of items */
    hierarchy: boolean;
    /** Determine if we all the alt key */
    allowAltModifier: boolean;
    /** Determine if we all the ctrl key */
    allowCtrlModifier: boolean;
    /** Determine if we allow the Home/End keys */
    allowBoundaryKeys: boolean;
    /** Determine if we should scroll the item into view on focus */
    shouldScrollInView: boolean;
    /** Store the instance of the focus key manager */
    focusKeyManager: FocusKeyManager<TabbableListItemDirective>;
    /** Indicate if we should refocus an item on QueryList change - for use within virtual lists */
    shouldFocusOnChange: boolean;
    /** Store the container element */
    containerRef: HTMLElement;
    /** Emit whenever focus does not change but tabindexes have */
    onTabIndexChange: Subject<void>;
    /** Determine if focus is currently within the tabbable list */
    isFocused: boolean;
    /** Store the list of tabbable items */
    private _items;
    /** Store the direction of the list */
    private _direction;
    /** Unsubscribe from all observables on destroy */
    private readonly _onDestroy;
    ngOnDestroy(): void;
    initialize(items: QueryList<TabbableListItemDirective>, direction: 'horizontal' | 'vertical', wrap: boolean): void;
    /** Give and item focus or just make it the current tabbable item */
    activate(item: TabbableListItemDirective, updateIndexOnly?: boolean): void;
    /** Give and item focus or just make it the current tabbable item */
    activateItemAtIndex(index: number, updateIndexOnly?: boolean): void;
    isItemActive(item: TabbableListItemDirective): boolean;
    setFirstItemTabbable(): void;
    isAnyItemTabbable(): boolean;
    ensureTabbableItem(): void;
    focusTabbableItem(): void;
    onKeydown(source: TabbableListItemDirective, event: KeyboardEvent): void;
    sortItemsByHierarchy(list: QueryList<TabbableListItemDirective>): TabbableListItemDirective[];
    /**
     * In a uxVirtualFor list cells can be resused. This means that when we scroll
     * the data associated with a given element may change and not the actual elements. If only the data changes
     * then the QueryList will not emit a change so we may show focus indicatator on the element that previously displayed
     * the correct data but no longer does.
     *
     * We need to handle this correctly here. We already have keys implements to handle virtual elements so we can check
     * if a key changes and use it to update the focused item even if the QueryList doesn't inform us that we have changed.
     */
    itemReferenceChange(previousKey: unknown, origin: FocusOrigin): void;
    /** Update the active item without causing focus */
    updateActiveItemIndex(index: number): void;
    /** Determine if there is an item with a tabindex of 0 */
    hasTabbableItem(): boolean;
    private getItemByKey;
    private flattenHierarchy;
    static ɵfac: i0.ɵɵFactoryDeclaration<TabbableListService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<TabbableListService>;
}