qgscheckablecombobox.h

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/***************************************************************************
                              qgscheckablecombobox.h
                              ------------------------
  begin                : March 21, 2017
  copyright            : (C) 2017 by Alexander Bruy
  email                : alexander dot bruy at gmail dot com
 ***************************************************************************/
 
/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSCHECKABLECOMBOBOX_H
#define QGSCHECKABLECOMBOBOX_H
 
#include "qgis.h"
#include "qgis_gui.h"
#include "qgis_sip.h"
 
#include <QComboBox>
#include <QMenu>
#include <QStandardItemModel>
#include <QStyledItemDelegate>
 
class QEvent;

#ifndef SIP_RUN
class QgsCheckableItemModel : public QStandardItemModel
{
    Q_OBJECT
 
  public:
    QgsCheckableItemModel( QObject *parent = nullptr );

    Qt::ItemFlags flags( const QModelIndex &index ) const override;

    QVariant data( const QModelIndex &index, int role = Qt::DisplayRole ) const override;

    bool setData( const QModelIndex &index, const QVariant &value, int role = Qt::EditRole ) override;
 
  signals:

    void itemCheckStateChanged( const QModelIndex &index );
};
 

class QgsCheckBoxDelegate : public QStyledItemDelegate
{
    Q_OBJECT
 
  public:
    QgsCheckBoxDelegate( QObject *parent = nullptr );

    void paint( QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index ) const override;
};
#endif

class GUI_EXPORT QgsCheckableComboBox : public QComboBox
{
    Q_OBJECT
 
    Q_PROPERTY( QString separator READ separator WRITE setSeparator )
    Q_PROPERTY( QString defaultText READ defaultText WRITE setDefaultText )
    Q_PROPERTY( QStringList checkedItems READ checkedItems WRITE setCheckedItems )
 
  public:
    QgsCheckableComboBox( QWidget *parent SIP_TRANSFERTHIS = nullptr );

    QString separator() const;

    void setSeparator( const QString &separator );

    QString defaultText() const;

    void setDefaultText( const QString &text );

    void addItemWithCheckState( const QString &text, Qt::CheckState state, const QVariant &userData = QVariant() );

    QStringList checkedItems() const;

    QVariantList checkedItemsData() const;

    Qt::CheckState itemCheckState( int index ) const;

    void setItemCheckState( int index, Qt::CheckState state );
 
#ifndef SIP_RUN
    template<class T> void setCheckedItemsFromFlags( const QFlags<T> &value )
    {
      const QMetaEnum metaEnum = QMetaEnum::fromType<T>();
      for ( int idx = 0; idx < metaEnum.keyCount(); ++idx )
      {
        setItemCheckState( findData( QVariant::fromValue( metaEnum.value( idx ) ) ), value.testFlag( static_cast< T >( metaEnum.value( idx ) ) ) ? Qt::CheckState::Checked : Qt::CheckState::Unchecked );
      }
    }

    template<class T> QFlags<T> flagsFromCheckedItems() const
    {
      QFlags<T> res;
      for ( int i = 0; i < count(); ++i )
      {
        if ( itemCheckState( i ) == Qt::CheckState::Checked )
        {
          res.setFlag( itemData( i ).value< T >(), true );
        }
      }
      return res;
    }
 
#endif

    void toggleItemCheckState( int index );

    QgsCheckableItemModel *model() const SIP_SKIP { return mModel; }

    void hidePopup() override;

    bool eventFilter( QObject *object, QEvent *event ) override;
 
  signals:

    void checkedItemsChanged( const QStringList &items );
 
  public slots:

    void setCheckedItems( const QStringList &items );
 
  protected:
    void resizeEvent( QResizeEvent *event ) override;
 
  protected slots:

    void showContextMenu( QPoint pos );

    void selectAllOptions();

    void deselectAllOptions();
 
  protected:
    QgsCheckableItemModel *mModel = nullptr;
 
  private:
    void updateCheckedItems();
    void updateDisplayText();
 
    QString mSeparator;
    QString mDefaultText;
 
    bool mSkipHide = false;
 
    QMenu *mContextMenu = nullptr;
    QAction *mSelectAllAction = nullptr;
    QAction *mDeselectAllAction = nullptr;
};
 
#endif // QGSCHECKABLECOMBOBOX_H