qgsfieldmodel.h

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/***************************************************************************
   qgsfieldmodel.h
    --------------------------------------
   Date                 : 01.04.2014
   Copyright            : (C) 2014 Denis Rouzaud
   Email                : [email protected]
***************************************************************************
*                                                                         *
*   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 QGSFIELDMODEL_H
#define QGSFIELDMODEL_H

#include <QAbstractItemModel>
#include <QItemSelectionModel>
#include <QComboBox>

#include "qgsvectorlayer.h"

class GUI_EXPORT QgsFieldModel : public QAbstractItemModel
{
    Q_OBJECT
  public:
    enum FieldRoles
    {
      FieldNameRole = Qt::UserRole + 1,  /* return field name if index corresponds to a field */
      FieldIndexRole = Qt::UserRole + 2, /* return field index if index corresponds to a field */
      ExpressionRole = Qt::UserRole + 3, /* return field name or expression */
      IsExpressionRole = Qt::UserRole + 4, /* return if index corresponds to an expression */
      ExpressionValidityRole = Qt::UserRole + 5, /* return if expression is valid or not */
      FieldTypeRole = Qt::UserRole + 6 /* return the field type (if a field, return QVariant if expression) */
    };

    explicit QgsFieldModel( QObject *parent = 0 );

    QModelIndex indexFromName( const QString &fieldName );

    void setAllowExpression( bool allowExpression );
    bool allowExpression() { return mAllowExpression; }

    bool isField( const QString& expression );

    void setExpression( const QString &expression );

    void removeExpression();

    QgsVectorLayer* layer() { return mLayer; }

  public slots:
    void setLayer( QgsVectorLayer *layer );

  protected slots:
    virtual void updateModel();

  private slots:
    void layerDeleted();

  protected:
    QgsFields mFields;
    QList<QString> mExpression;

    QgsVectorLayer* mLayer;
    bool mAllowExpression;

  private:
    void fetchFeature();

    // QAbstractItemModel interface
  public:
    QModelIndex index( int row, int column, const QModelIndex &parent = QModelIndex() ) const override;
    QModelIndex parent( const QModelIndex &child ) const override;
    int rowCount( const QModelIndex &parent = QModelIndex() ) const override;
    int columnCount( const QModelIndex &parent ) const override;
    QVariant data( const QModelIndex &index, int role ) const override;
};

#endif // QGSFIELDMODEL_H