/* * Copyright 2008 by Rob Scheepmaker * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301 USA */ #ifndef PLASMA_EXTENDER_H #define PLASMA_EXTENDER_H #include #include "plasma/plasma_export.h" namespace Plasma { class ExtenderPrivate; class ExtenderItem; class Applet; /** * @class Extender plasma/extender.h * * @short Extends applets to allow detachable parts * * An Extender is a widget that visually extends the normal contents of an applet with * additional dynamic widgets called ExtenderItems. These ExtenderItems can be * detached by the user and dropped either on another Extender or on the canvas directly. * * This widget allows using ExtenderItems in your applet. Extender takes care of the presentation * of a collection of ExtenderItems and keeps track of ExtenderItems that originate in it. * * The default Extender implementation displays extender items in a vertical layout with * spacers that appear when dropping an ExtenderItem over it. * * If you wish to have a different presentation of extender items, you can choose to subclass * Extender and reimplement the extenderItem* events and, optionally, the saveState function. */ class PLASMA_EXPORT Extender : public QGraphicsWidget { Q_OBJECT Q_PROPERTY(QString emptyExtenderMessage READ emptyExtenderMessage WRITE setEmptyExtenderMessage) public: /** * Creates an extender. Note that extender expects applet to have a config(), and needs a * scene because of that. So you should only instantiate an extender in init() or later, not * in an applet's constructor. * @param applet The applet this extender is part of. Null is not allowed here. */ explicit Extender(Applet *applet); ~Extender(); /** * @param emptyExtenderMessage The text to be shown whenever the applet's extender is empty. * Defaults to i18n'ed "no items". */ void setEmptyExtenderMessage(const QString &message); /** * @return The text to be shown whenever the applet's layout is empty. */ QString emptyExtenderMessage() const; /** * @returns a list of all extender items (attached AND detached) where the source applet is * this applet. */ QList items() const; /** * @returns a list of all attached extender items. */ QList attachedItems() const; /** * @returns a list of all detached extender items. */ QList detachedItems() const; /** * This function can be used for easily determining if a certain item is allready displayed * in a extender item somewhere, so your applet doesn't duplicate this item. Say the applet * displays 'jobs', from an engine which add's a source for every job. In sourceAdded you * could do something like: * if (!extenderItem(source)) { * //add an extender item monitoring this source. * } */ ExtenderItem *item(const QString &name) const; protected: /** * Get's called after an item has been added to this extender. The bookkeeping has allready * been done when this function get's called. The only thing left to do is put it somewhere * appropriate. The default implementation adds the extenderItem to the appropriate place in * a QGraphicsLinearLayout. * @param item The item that has just been added. * @param pos The location the item has been dropped in local coordinates. */ virtual void itemAddedEvent(ExtenderItem *item, const QPointF &pos); /** * Get's called after an item has been removed from this extender. All bookkeeping has * allready been done when this function get's called. * @param item The item that has just been removed. */ virtual void itemRemovedEvent(ExtenderItem *item); /** * Get's called when an ExtenderItem that get's dragged enters this extender. Default * implementation does nothing. */ virtual void itemHoverEnterEvent(ExtenderItem *item); /** * Gets called when an ExtenderItem is hovering over this extender. Implement this function * to give some visual feedback about what will happen when the mouse button is released at * that position. The default implementation shows a spacer at the appropriate location in * the layout. * @param item The item that's hovering over this extender. Most usefull for obtaining the * size of the spacer. * @param pos The location the item is hovering. */ virtual void itemHoverMoveEvent(ExtenderItem *item, const QPointF &pos); /** * Get's called when an ExtenderItem that was previously hovering over this extender moves * away from this extender. The default implementation removes any spacer from the layout. */ virtual void itemHoverLeaveEvent(ExtenderItem *item); /** * This function get's called for every extender when plasma exits. Implement this function * to store the current state of this extender (position in a layout for example), so this * can be restored when applet starts again. The default implementation stores the y * coordinate of every extender item in the config field extenderItemPos. */ virtual void saveState(); /** * @reimplemented from QGraphicsWidget */ QVariant itemChange(GraphicsItemChange change, const QVariant &value); /** * @reimplemented from QGraphicsWidget */ void resizeEvent(QGraphicsSceneResizeEvent *event); Q_SIGNALS: /** * Fires when an extender item is added to this extender. */ void itemAttached(Plasma::ExtenderItem *); /** * Fires when an extender item is removed from this extender. */ void itemDetached(Plasma::ExtenderItem *); /** * Fires when an extender's preferred size changes. */ void geometryChanged(); private: ExtenderPrivate* const d; friend class ExtenderPrivate; friend class ExtenderItem; friend class ExtenderItemPrivate; //applet should be able to call saveState(); friend class Applet; }; } // Plasma namespace #endif //PLASMA_EXTENDER_H