qgsexpressionbuilderwidget.h

Go to the documentation of this file.

/***************************************************************************
    qgisexpressionbuilderwidget.h - A genric expression string builder widget.
     --------------------------------------
    Date                 :  29-May-2011
    Copyright            : (C) 2011 by Nathan Woodrow
    Email                : woodrow.nathan 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 QGSEXPRESSIONBUILDER_H
#define QGSEXPRESSIONBUILDER_H

#include <QWidget>
#include "ui_qgsexpressionbuilder.h"
#include "qgsvectorlayer.h"
#include "qgsexpressionhighlighter.h"
#include "qgsdistancearea.h"

#include "QStandardItemModel"
#include "QStandardItem"
#include "QSortFilterProxyModel"
#include "QStringListModel"

class QgsExpressionItem : public QStandardItem
{
  public:
    enum ItemType
    {
      Header,
      Field,
      ExpressionNode
    };

    QgsExpressionItem( const QString& label,
                       const QString& expressionText,
                       const QString& helpText,
                       QgsExpressionItem::ItemType itemType = ExpressionNode )
        : QStandardItem( label )
    {
      mExpressionText = expressionText;
      mHelpText = helpText;
      mType = itemType;
      setData( itemType, ItemTypeRole );
    }

    QgsExpressionItem( const QString& label,
                       const QString& expressionText,
                       QgsExpressionItem::ItemType itemType = ExpressionNode )
        : QStandardItem( label )
    {
      mExpressionText = expressionText;
      mType = itemType;
      setData( itemType, ItemTypeRole );
    }

    QString getExpressionText() const { return mExpressionText; }

    QString getHelpText() const { return mHelpText; }
    void setHelpText( const QString& helpText ) { mHelpText = helpText; }

    QgsExpressionItem::ItemType getItemType() const { return mType; }

    static const int CustomSortRole = Qt::UserRole + 1;
    static const int ItemTypeRole = Qt::UserRole + 2;

  private:
    QString mExpressionText;
    QString mHelpText;
    QgsExpressionItem::ItemType mType;

};

class GUI_EXPORT QgsExpressionItemSearchProxy : public QSortFilterProxyModel
{
    Q_OBJECT

  public:
    QgsExpressionItemSearchProxy();

    bool filterAcceptsRow( int source_row, const QModelIndex &source_parent ) const override;

  protected:

    bool lessThan( const QModelIndex &left, const QModelIndex &right ) const override;
};


class GUI_EXPORT QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExpressionBuilderWidgetBase
{
    Q_OBJECT
  public:
    QgsExpressionBuilderWidget( QWidget* parent = nullptr );
    ~QgsExpressionBuilderWidget();

    void setLayer( QgsVectorLayer* layer );

    void loadFieldNames();

    void loadFieldNames( const QgsFields& fields );

    void loadFieldsAndValues( const QMap<QString, QStringList>& fieldValues );

    void setGeomCalculator( const QgsDistanceArea & da );

    QString expressionText();

    void setExpressionText( const QString& expression );

    QgsExpressionContext expressionContext() const { return mExpressionContext; }

    void setExpressionContext( const QgsExpressionContext& context );

    void registerItem( const QString& group, const QString& label, const QString& expressionText,
                       const QString& helpText = "",
                       QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode,
                       bool highlightedItem = false, int sortOrder = 1 );

    bool isExpressionValid();

    void saveToRecent( const QString& collection = "generic" );

    void loadRecent( const QString& collection = "generic" );

    void newFunctionFile( const QString& fileName = "scratch" );

    void saveFunctionFile( QString fileName );

    void loadCodeFromFile( QString path );

    void loadFunctionCode( const QString& code );

    void updateFunctionFileList( const QString& path );

  public slots:

    void loadSampleValues();

    void loadAllValues();

    void autosave();

    void setAutoSave( bool enabled ) { mAutoSave = enabled; }

  private slots:
    void showContextMenu( QPoint );
    void setExpressionState( bool state );
    void currentChanged( const QModelIndex &index, const QModelIndex & );
    void operatorButtonClicked();
    void on_btnRun_pressed();
    void on_btnNewFile_pressed();
    void on_cmbFileNames_currentItemChanged( QListWidgetItem* item, QListWidgetItem* lastitem );
    void on_expressionTree_doubleClicked( const QModelIndex &index );
    void on_txtExpressionString_textChanged();
    void on_txtSearchEdit_textChanged();
    void on_txtSearchEditValues_textChanged();
    void on_lblPreview_linkActivated( const QString& link );
    void on_mValuesListView_doubleClicked( const QModelIndex &index );
    void on_txtPython_textChanged();

  signals:
    void expressionParsed( bool isValid );

  protected:
    void showEvent( QShowEvent *e );

  private:
    void runPythonCode( const QString& code );
    void updateFunctionTree();
    void fillFieldValues( const QString &fieldName, int countLimit );
    QString loadFunctionHelp( QgsExpressionItem* functionName );
    QString helpStylesheet() const;

    void loadExpressionContext();

    void registerItemForAllGroups( const QStringList& groups, const QString& label, const QString& expressionText,
                                   const QString& helpText = "",
                                   QgsExpressionItem::ItemType type = QgsExpressionItem::ExpressionNode,
                                   bool highlightedItem = false, int sortOrder = 1 );

    bool mAutoSave;
    QString mFunctionsPath;
    QgsVectorLayer *mLayer;
    QStandardItemModel *mModel;
    QStringListModel *mValuesModel;
    QSortFilterProxyModel *mProxyValues;
    QgsExpressionItemSearchProxy *mProxyModel;
    QMap<QString, QgsExpressionItem*> mExpressionGroups;
    QgsFeature mFeature;
    QgsExpressionHighlighter* highlighter;
    bool mExpressionValid;
    QgsDistanceArea mDa;
    QString mRecentKey;
    QMap<QString, QStringList> mFieldValues;
    QgsExpressionContext mExpressionContext;
};

#endif // QGSEXPRESSIONBUILDER_H