import { IDisposable } from 'phosphor-disposable';
import { ISignal } from 'phosphor-signaling';
import { Widget } from 'phosphor-widget';
/**
 * An object that tracks the active widget in an application.
 */
export declare class WidgetTracker<T extends Widget> implements IDisposable {
    /**
     * Construct a new widget tracker.
     */
    constructor();
    /**
     * A signal emitted when the active widget changes.
     */
    activeWidgetChanged: ISignal<WidgetTracker<T>, T>;
    /**
     * Test whether the widget tracker has been disposed.
     *
     * #### Notes
     * This is a read-only property.
     */
    isDisposed: boolean;
    /**
     * The read-only list of tracked widgets.
     *
     * #### Notes
     * This is a read-only property.
     */
    widgets: T[];
    /**
     * The currently active widget.
     *
     * #### Notes
     * This is set automatically due to user events but can
     * also be set programatically.
     * The widget must be one of the current widgets.
     * The widget will be activated in the application shell.
     * The [[activeWidgetChanged]] signal will be emitted.
     */
    activeWidget: T;
    /**
     * Dispose of the resources used by the tracker.
     */
    dispose(): void;
    /**
     * Add a widget to the widget tracker.
     *
     * @param widget - The widget to add to the tracker.
     *
     * @returns A disposable that can be used to remove the widget from
     *   the tracker.
     *
     * #### Notes
     * The new widget will be set as the active widget.
     */
    addWidget(widget: T): IDisposable;
    /**
     * Handle the DOM events for the widget tracker.
     *
     * @param event - The DOM event sent to the widget.
     */
    handleEvent(event: Event): void;
    private _widgets;
    private _activeWidget;
}