qgsfieldexpressionwidget.h

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/***************************************************************************
   qgsfieldexpressionwidget.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 QGSFIELDEXPRESSIONWIDGET_H
#define QGSFIELDEXPRESSIONWIDGET_H

#include <QSharedPointer>
#include <QWidget>
#include <QToolButton>
#include <QComboBox>
#include <QColor>

#include "qgsdistancearea.h"
#include "qgsfieldproxymodel.h"

class QgsMapLayer;
class QgsVectorLayer;


class GUI_EXPORT QgsFieldExpressionWidget : public QWidget
{
    Q_OBJECT
    Q_PROPERTY( QString expressionDialogTitle READ expressionDialogTitle WRITE setExpressionDialogTitle )
    Q_FLAGS( QgsFieldProxyModel::Filters )
    Q_PROPERTY( QgsFieldProxyModel::Filters filters READ filters WRITE setFilters )

  public:
    explicit QgsFieldExpressionWidget( QWidget *parent = nullptr );

    void setExpressionDialogTitle( const QString& title );

    const QString expressionDialogTitle() { return mExpressionDialogTitle; }

    void setFilters( const QgsFieldProxyModel::Filters& filters );

    void setLeftHandButtonStyle( bool isLeft );

    QgsFieldProxyModel::Filters filters() const { return mFieldProxyModel->filters(); }

    void setGeomCalculator( const QgsDistanceArea &da );

    QString currentField( bool *isExpression = nullptr, bool *isValid = nullptr ) const;

    bool isValidExpression( QString *expressionError = nullptr ) const;

    bool isExpression() const;

    QString currentText() const;

    QString asExpression() const;

    QgsVectorLayer* layer() const;

    typedef QgsExpressionContext( *ExpressionContextCallback )( const void* context );

    void registerGetExpressionContextCallback( ExpressionContextCallback fnGetExpressionContext, const void* context );

  signals:
    void fieldChanged( const QString& fieldName );

    void fieldChanged( const QString& fieldName, bool isValid );

//    void returnPressed();

  public slots:
    void setLayer( QgsVectorLayer* layer );

    void setLayer( QgsMapLayer* layer );

    void setField( const QString &fieldName );

  protected slots:
    void editExpression();

    void expressionEdited( const QString& expression );

    void expressionEditingFinished();

    void currentFieldChanged();

    void updateLineEditStyle( const QString& expression = QString() );

    bool isExpressionValid( const QString& expressionStr );

  protected:
    void changeEvent( QEvent* event ) override;

  private slots:
    void reloadLayer();

    void beforeResetModel();
    void afterResetModel();

  private:
    QComboBox* mCombo;
    QToolButton* mButton;
    QgsFieldProxyModel* mFieldProxyModel;
    QString mExpressionDialogTitle;
    QSharedPointer<const QgsDistanceArea> mDa;
    QScopedPointer< QgsExpressionContext > mExpressionContext;
    ExpressionContextCallback mExpressionContextCallback;
    const void* mExpressionContextCallbackContext;
    QString mBackupExpression;

    friend class TestQgsFieldExpressionWidget;
};

#endif // QGSFIELDEXPRESSIONWIDGET_H