plasma-framework/extenders/extenderitem.h

/*
 * Copyright 2008, 2009 by Rob Scheepmaker <r.scheepmaker@student.utwente.nl>
 *
 * 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_EXTENDERITEM_H
#define PLASMA_EXTENDERITEM_H

#include <QtGui/QGraphicsWidget>

#include <kconfiggroup.h>
#include <kicon.h>

#include "plasma/plasma_export.h"

namespace Plasma
{

class Applet;
class Extender;
class ExtenderGroup;
class ExtenderItemPrivate;

/**
 * @class ExtenderItem plasma/extenderitem.h <Plasma/ExtenderItem>
 *
 * @short Provides detachable items for an Extender
 *
 * This class wraps around a QGraphicsWidget and provides drag&drop handling, a draghandle,
 * title and ability to display qactions as a row of icon, ability to expand, collapse, return
 * to source and tracks configuration associated with this item for you.
 *
 * Typical usage of ExtenderItems in your applet could look like this:
 *
 * @code
 * if (!extender()->hasItem("networkmonitoreth0")) {
 *     ExtenderItem *item = new ExtenderItem(extender());
 *     //name can be used to later access this item through extender()->item(name):
 *     item->setName("networkmonitoreth0");
 *     item->config().writeEntry("device", "eth0");
 *     initExtenderItem(item);
 * }
 * @endcode
 *
 * Note that we first check if the item already exists: ExtenderItems are persistent
 * between sessions so we can't blindly add items since they might already exist.
 *
 * You'll then need to implement the initExtenderItem function. Having this function in your applet
 * makes sure that detached extender items get restored after plasma is restarted, just like applets
 * are. That is also the reason that we write an entry in item->config().
 * In this function you should instantiate a QGraphicsWidget or QGraphicsItem and call the
 * setWidget function on the ExtenderItem. This is the only correct way of adding actual content to
 * a extenderItem. An example:
 *
 * @code
 * void MyApplet::initExtenderItem(Plasma::ExtenderItem *item)
 * {
 *     QGraphicsWidget *myNetworkMonitorWidget = new NetworkMonitorWidget(item);
 *     dataEngine("networktraffic")->connectSource(item->config().readEntry("device", ""),
 *                                                 myNetworkMonitorWidget);
 *     item->setWidget(myNetworkMonitorWidget);
 * }
 * @endcode
 *
 */
class PLASMA_EXPORT ExtenderItem : public QGraphicsWidget
{
    Q_OBJECT
    Q_PROPERTY(QGraphicsItem * widget READ widget WRITE setWidget)
    Q_PROPERTY(QString title READ title WRITE setTitle)
    Q_PROPERTY(QString name READ name WRITE setName)
    Q_PROPERTY(QIcon icon READ icon WRITE setIcon)
    Q_PROPERTY(Extender * extender READ extender WRITE setExtender)
    Q_PROPERTY(bool collapsed READ isCollapsed WRITE setCollapsed)
    Q_PROPERTY(bool detached READ isDetached)
    Q_PROPERTY(uint autoExpireDelay READ autoExpireDelay WRITE setAutoExpireDelay)

    public:
        /**
         * The constructor takes care of adding this item to an extender.
         * @param hostExtender The extender the extender item belongs to.
         * @param extenderItemId the id of the extender item. Use the default 0 to assign a new,
         * unique id to this extender item.
         */
        explicit ExtenderItem(Extender *hostExtender, uint extenderItemId = 0);

        ~ExtenderItem();

        /**
         * fetch the configuration of this widget.
         * @return the configuration of this widget.
         */
        KConfigGroup config() const;

        /**
         * @param widget The widget that should be wrapped into the extender item.
         */
        void setWidget(QGraphicsItem *widget);

        /**
         * @return The widget that is wrapped into the extender item.
         */
        QGraphicsItem *widget() const;

        /**
         * @param title the title that will be shown in the extender item's dragger. Default is
         * no title. This title will also be stored in the item's configuration, so you don't have
         * to manually store/restore this information for your extender items.
         */
        void setTitle(const QString &title);

        /**
         * @return the title shown in the extender item's dragger.
         */
        QString title() const;

        /**
         * You can assign names to extender items to look them up through the item() function.
         * Make sure you only use unique names. This name will be stored in the item's
         * configuration.
         * @param name the name of the item. Defaults to an empty string.
         */
        void setName(const QString &name);

        /**
         * @return the name of the item.
         */
        QString name() const;

        /**
         * @param icon the icon name to display in the extender item's
         * drag handle. Defaults to the source applet's icon. This icon name will also be stored
         * in the item's configuration, so you don't have to manually store/restore this
         * information.
         */
        void setIcon(const QString &icon);

        /**
         * @param icon the icon to display in the extender item's drag handle. Defaults to the
         * source applet's icon.
         */
        void setIcon(const QIcon &icon);

        /**
         * @return the icon being displayed in the extender item's drag handle.
         */
        QIcon icon() const;

        /**
         * @param extender the extender this item belongs to.
         * @param pos the position in the extender this item should be added. Defaults to 'just
         * append'.
         */
        void setExtender(Extender *extender, const QPointF &pos = QPointF(-1, -1));

        /**
         * @return the extender this items belongs to.
         */
        Extender *extender() const;

        /**
         * @param group the group you want this item to belong to. Note that you can't nest
         * ExtenderGroups.
         * @since 4.3
         */
        void setGroup(ExtenderGroup *group);

        /**
         * @returns the group this item belongs to.
         * @since 4.3
         */
        ExtenderGroup *group() const;

        /**
         * @returns whether or not this is an ExtenderGroup.
         * @since 4.3
         */
        bool isGroup() const;

        /**
         * @param time (in ms) before this extender item destroys itself unless it is detached,
         * in which case this extender stays around. 0 means forever and is the default.
         */
        void setAutoExpireDelay(uint time);

        /**
         * @return whether or not this extender item has an auto expire delay.
         */
        uint autoExpireDelay() const;

        /**
         * @return whether or not this item is detached from its original source.
         */
        bool isDetached() const;

        /**
         * @return whether or not the extender item  is collapsed.
         */
        bool isCollapsed() const;

        /**
         * @param name the name to store the action under in our collection.
         * @param action the action to add. Actions will be displayed as an icon in the drag
         * handle.
         */
        void addAction(const QString &name, QAction *action);

        /**
         * @return the QAction with the given name from our collection. By default the action
         * collection contains a "movebacktosource" action which will be only shown when the
         * item is detached.
         */
        QAction *action(const QString &name) const;

    public Q_SLOTS:
        /**
         * Destroys the extender item. As opposed to calling delete on this class, destroy also
         * removes the config group associated with this item.
         */
        void destroy();

        /**
         * Collapse or expand the extender item. Defaults to false.
         */
        void setCollapsed(bool collapsed);

        /**
         * Returns the extender item to its source applet.
         */
        void returnToSource();

        /**
         * Shows a close button in this item's drag handle. By default a close button will not be
         * shown.
         */
        void showCloseButton();

        /**
         * Hides the close button in this item's drag handle.
         */
        void hideCloseButton();

    Q_SIGNALS:
        /**
         * Emitted when the extender item is destroyed
         * @since 4.4.1
         */
        void destroyed(ExtenderItem *item);

    protected:
        void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);

        void moveEvent(QGraphicsSceneMoveEvent *event);
        void resizeEvent(QGraphicsSceneResizeEvent *event);

        void mousePressEvent(QGraphicsSceneMouseEvent *event);
        void mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event);
        void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
        void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);

        void hoverMoveEvent(QGraphicsSceneHoverEvent *event);
        void hoverLeaveEvent(QGraphicsSceneHoverEvent *event);

        bool sceneEventFilter(QGraphicsItem *watched, QEvent *event);

        QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint) const;

    private:
        Q_PRIVATE_SLOT(d, void toggleCollapse())
        Q_PRIVATE_SLOT(d, void updateToolBox())
        Q_PRIVATE_SLOT(d, void themeChanged())
        Q_PRIVATE_SLOT(d, void sourceAppletRemoved())
        Q_PRIVATE_SLOT(d, void actionDestroyed(QObject*))

        ExtenderItemPrivate * const d;

        friend class Applet;
        friend class Extender;
        friend class ExtenderPrivate;
        friend class ExtenderItemPrivate;
};
} // namespace Plasma
#endif // PLASMA_EXTENDERITEM_H