kget/ui/kextendableitemdelegate.h

   1 /* This file is part of the KDE libraries
   2     Copyright (C) 2006,2007 Andreas Hartmetz (ahartmetz@gmail.com)
   3
   4     This library is free software; you can redistribute it and/or
   5     modify it under the terms of the GNU Library General Public
   6     License as published by the Free Software Foundation; either
   7     version 2 of the License, or (at your option) any later version.
   8
   9     This library is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12     Library General Public License for more details.
  13
  14     You should have received a copy of the GNU Library General Public License
  15     along with this library; see the file COPYING.LIB.  If not, write to
  16     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17     Boston, MA 02110-1301, USA.
  18 */
  19
  20
  21 #ifndef KEXTENDABLEITEMDELEGATE_H
  22 #define KEXTENDABLEITEMDELEGATE_H
  23
  24 #include <QItemDelegate>
  25 #include <QHash>
  26
  27 /**
  28 This delegate makes it possible to display an arbitrary QWidget ("extender") that spans all columns below a line of items.
  29 The extender will logically belong to a column in the row above it.
  30
  31
  32 It is your responsibility to devise a way to trigger extension and contraction of items, by calling
  33 extendItem() and contractItem(). You can e.g. reimplement itemActivated() and similar functions.
  34 */
  35
  36
  37 class QAbstractItemView;
  38 class KExtendableItemDelegatePrivate;
  39
  40 class KExtendableItemDelegate : public QItemDelegate {
  41         Q_OBJECT
  42
  43 public:
  44         enum auxDataRoles {ShowExtensionIndicatorRole = Qt::UserRole + 200};
  45
  46         /**
  47          * Create a new KExtendableItemDelegate that belongs to @p parent. In contrast to generic
  48          * QAbstractItemDelegates, an instance of this class can only ever be the delegate for one
  49          * instance of af QAbstractItemView subclass.
  50          */
  51         KExtendableItemDelegate(QAbstractItemView *parent);
  52         virtual ~KExtendableItemDelegate();
  53
  54         //reimplemented from QItemDelegate
  55         virtual QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const;
  56         virtual void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;
  57
  58         /**
  59          * Insert the @p extender that logically belongs to @p index into the view.
  60          * If you need a parent for the extender at construction time, use the itemview's viewport().
  61          * The extender will be reparented and resized to the viewport by this function.
  62          */
  63         void extendItem(QWidget *extender, const QModelIndex &index);
  64
  65     /**
  66      * Remove the extender that logically belongs to @p index from the view.
  67          */
  68         void contractItem(const QModelIndex &index);
  69
  70         /**
  71          * Return whether there is an extender that belongs to @p index.
  72          */
  73         bool isExtended(const QModelIndex &index) const;
  74
  75         /**
  76          * Reimplement this function to adjust the internal geometry of the extender.
  77          * The external geometry of the extender will be set by the delegate.
  78          */
  79         virtual void updateExtenderGeometry(QWidget *extender, const QStyleOptionViewItem &option, const QModelIndex &index) const;
  80
  81 Q_SIGNALS:
  82         /**
  83          * This signal indicates that the item at @p index was extended with @p extender.
  84          */
  85         void extenderCreated(QWidget *extender, const QModelIndex &index);
  86
  87         /**
  88          * This signal indicates that the @p extender belonging to @p index has emitted the destroyed() signal.
  89          */
  90         void extenderDestroyed(QWidget *extender, const QModelIndex &index);
  91
  92 protected:
  93         /**
  94          * Reimplement this function to fine-tune the position of the extender. @p option.rect will be a rectangle
  95          * that is as wide as the viewport and as high as the usual item height plus the extender size hint's height.
  96          * Its upper left corner will be at the upper left corner of the usual item.
  97          * You can place the returned rectangle of this function anywhere inside that area.
  98          */
  99         QRect extenderRect(QWidget *extender, const QStyleOptionViewItem &option, const QModelIndex &index) const;
 100         //these two must have the same (screen) size!
 101         void setExtendIcon(const QPixmap &);
 102         void setContractIcon(const QPixmap &);
 103         QPixmap extendIcon();
 104         QPixmap contractIcon();
 105
 106 private Q_SLOTS:
 107         void extenderDestructionHandler(QObject *destroyed);
 108
 109 private:
 110         inline QSize maybeExtendedSize(const QStyleOptionViewItem &option, const QModelIndex &index) const;
 111         QModelIndex indexOfExtendedColumnInSameRow(const QModelIndex &index) const;
 112         inline void scheduleUpdateViewLayout() const;
 113
 114         KExtendableItemDelegatePrivate *const d;
 115 };
 116 #endif // KEXTENDABLEITEMDELEGATE_H