TreeComboBox.h

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/*
  TreeComboBox
  https://github.com/mpaperno/maxLibQt

  COPYRIGHT: (c)2017 Maxim Paperno; All Right Reserved.
  Contact: http://www.WorldDesign.com/contact

  LICENSE:

  Commercial License Usage
  Licensees holding valid commercial licenses may use this file in
  accordance with the terms contained in a written agreement between
  you and the copyright holder.

  GNU General Public License Usage
  Alternatively, this file may be used under the terms of the GNU
  General Public License as published by the Free Software Foundation,
  either version 3 of the License, or (at your option) any later version.

  This program 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 General Public License for more details.

  A copy of the GNU General Public License is available at <http://www.gnu.org/licenses/>.
*/

#ifndef TREECOMBOBOX_H
#define TREECOMBOBOX_H

#include <QComboBox>
#include <QStyledItemDelegate>
#include <QTreeView>
#include <QModelIndex>
#include <QScrollBar>

class QPainter;

class TreeComboItemDelegate : public QStyledItemDelegate
{
    Q_OBJECT

  public:
    explicit TreeComboItemDelegate(QObject *parent = Q_NULLPTR) : QStyledItemDelegate(parent) {}

    static bool isSeparator(const QModelIndex &index);
    static bool isParent(const QModelIndex &index);
    static void setSeparator(QAbstractItemModel *model, const QModelIndex &index);
    static void setParent(QAbstractItemModel *model, const QModelIndex &index, const bool selectable = false);

  protected:
    virtual void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;
    virtual QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const Q_DECL_OVERRIDE;
};


class TreeComboBox : public QComboBox
{
    Q_OBJECT
    Q_PROPERTY(bool autoData READ autoData WRITE setAutoData)

  public:
    explicit TreeComboBox(QWidget * parent = Q_NULLPTR);

    void setModel(QAbstractItemModel *model);
    void setView(QAbstractItemView *itemView = Q_NULLPTR);  // only QTreeView and derived
    inline QTreeView * view() const { return m_view; }
    inline bool autoData() const    { return m_autoData; }

    int currentIndex() const;
    QVariant currentData(int role = Qt::UserRole) const;
    QVariant itemData(int index, int role = Qt::UserRole) const;
    QIcon itemIcon(int index) const;
    inline QString itemText(int index) const { return itemData(index, Qt::DisplayRole).toString(); }

    void setItemData(const QModelIndex &index, const QVariant &value, int role = Qt::UserRole);
    void setItemData(int index, const QVariant &value, int role = Qt::UserRole) { setItemData(m_indexMap.value(index, QModelIndex()), value, role); }
    void setItemText(int index, const QString &text)                            { setItemData(index, QVariant::fromValue(text), Qt::EditRole); }
    void setItemIcon(int index, const QIcon &icon)                              { setItemData(index, QVariant::fromValue(icon), Qt::DecorationRole); }

    int findData(const QVariant &data, int role = Qt::UserRole, Qt::MatchFlags flags = Qt::MatchFlags(Qt::MatchExactly | Qt::MatchCaseSensitive)) const;
    inline int findText(const QString &text,
                        Qt::MatchFlags flags = Qt::MatchFlags(Qt::MatchExactly | Qt::MatchCaseSensitive)) const { return findData(text, Qt::DisplayRole, flags); }

    QModelIndex insertItem(int index, const QMap<int, QVariant> &values = QMap<int, QVariant>(), const QModelIndex &parentIndex = QModelIndex(), const bool reload = true);

    QModelIndex insertItem(int index, const QIcon & icon, const QString &text, const QModelIndex &parentIndex,  const QVariant &userData = QVariant(), const bool reload = true);

    void insertItems(int index, const QStringList &texts, const QModelIndex &parentIndex);

    // in addition to regular QComboBox add/insert, these allow specifying a parent item instead of the default root
    inline QModelIndex addItem(const QString &text, const QModelIndex &parentIndex,
                               const QVariant &userData = QVariant())                                   { return addItem(QIcon(), text, parentIndex, userData); }
    inline QModelIndex addItem(const QIcon &icon, const QString &text, const QModelIndex &parentIndex,
                               const QVariant &userData = QVariant())                                   { return insertItem(model()->rowCount(parentIndex), icon, text, parentIndex, userData); }
    inline void addItems(const QStringList &texts, const QModelIndex &parentIndex)                      { insertItems(model()->rowCount(parentIndex), texts, parentIndex); }

    // re-implement QComboBox add/insert interface
    inline void insertItem(int index, const QIcon &icon, const QString &text,
                           const QVariant &userData = QVariant())                                       { insertItem(index, icon, text, QModelIndex(), userData); }
    inline void addItem(const QString &text, const QVariant &userData = QVariant())                     { insertItem(count(), QIcon(), text, userData); }
    inline void addItem(const QIcon &icon, const QString &text, const QVariant &userData = QVariant())  { insertItem(count(), icon, text, userData); }
    inline void insertItem(int index, const QString &text, const QVariant &userData = QVariant())       { insertItem(index, QIcon(), text, userData); }
    inline void addItems(const QStringList &texts)                                                      { insertItems(count(), texts); }
    inline void insertItems(int index, const QStringList &texts)                                        { insertItems(index, texts, QModelIndex()); }

    // parent items (convenience functions insted of creating own data model)
    QModelIndex insertParentItem(int index, const QIcon &icon, const QString &text, const bool selectable = false,
                                 const QModelIndex &parentIndex = QModelIndex(), const QVariant &userData = QVariant());
    inline QModelIndex addParentItem(const QString &text, const bool selectable = false, const QModelIndex &parentIndex = QModelIndex(),
                                     const QVariant &userData = QVariant())                             { return addParentItem(QIcon(), text, selectable, parentIndex, userData); }
    inline QModelIndex addParentItem(const QIcon &icon, const QString &text, const bool selectable = false, const QModelIndex &parentIndex = QModelIndex(),
                                     const QVariant &userData = QVariant())                             { return insertParentItem(model()->rowCount(parentIndex), icon, text, selectable, parentIndex, userData); }

    virtual void wheelEvent(QWheelEvent *event) Q_DECL_OVERRIDE;
    virtual void keyPressEvent(QKeyEvent *event) Q_DECL_OVERRIDE;
    virtual bool eventFilter(QObject *object, QEvent *event) Q_DECL_OVERRIDE;
    virtual void showPopup() Q_DECL_OVERRIDE;
    virtual void hidePopup() Q_DECL_OVERRIDE;

  public slots:
    void clear();
    void setCurrentIndex(int index);
    void setCurrentIndex(const QModelIndex &index);
    void setCurrentText(const QString &text) { setCurrentIndex(findText(text)); }

    int setCurrentData(const QVariant &data, const int defaultIdx = -1, int role = Qt::UserRole, Qt::MatchFlags flags = Qt::MatchFlags(Qt::MatchExactly | Qt::MatchCaseSensitive));
    void keyboardSearchString(const QString &text);
    void setAutoData(bool enable) { m_autoData = enable; }

  signals:
    void currentModelIndexChanged(const QModelIndex &index);
    void currentDataChanged(const QVariant &data);  

  protected slots:
    int buildMap(QModelIndex parent = QModelIndex(), int row = 0);
    void reloadModel();
    void ensureCurrentExpanded();
    void adjustPopupWidth();
    void adjustPopupHeight();

  protected:
    QModelIndex indexAbove(QModelIndex index);
    QModelIndex indexBelow(QModelIndex index);
    QModelIndex lastIndex(const QModelIndex &index);
    bool usePopup(QStyleOptionComboBox *option = NULL);

    QTreeView * m_view;
    QMap<QPersistentModelIndex, int> m_rowMap;
    QMap<int, QPersistentModelIndex> m_indexMap;
    QPersistentModelIndex m_currentIndex;
    int m_nextDataId;
    bool m_autoData;
    bool m_skipNextHide;
};


class TreeComboBoxView : public QTreeView
{
  Q_OBJECT
  public:
    inline void adjustWidth(int maxWidth) {
      resizeColumnToContents(0);
      setMaximumWidth(maxWidth);
      setMinimumWidth(qMin(qMax(sizeHintForColumn(0), minimumSizeHint().width()), maxWidth) + verticalScrollBar()->sizeHint().width() + indentation());
    }
};

#endif // TREECOMBOBOX_H