QGIS API Documentation  2.13.0-Master
qgsfieldexpressionwidget.h
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1 /***************************************************************************
2  qgsfieldexpressionwidget.h
3  --------------------------------------
4  Date : 01.04.2014
5  Copyright : (C) 2014 Denis Rouzaud
6  Email : [email protected]
7 ***************************************************************************
8 * *
9 * This program is free software; you can redistribute it and/or modify *
10 * it under the terms of the GNU General Public License as published by *
11 * the Free Software Foundation; either version 2 of the License, or *
12 * (at your option) any later version. *
13 * *
14 ***************************************************************************/
15 
16 #ifndef QGSFIELDEXPRESSIONWIDGET_H
17 #define QGSFIELDEXPRESSIONWIDGET_H
18 
19 #include <QSharedPointer>
20 #include <QWidget>
21 #include <QToolButton>
22 #include <QComboBox>
23 #include <QColor>
24 
25 #include "qgsdistancearea.h"
26 #include "qgsfieldproxymodel.h"
27 
28 class QgsMapLayer;
29 class QgsVectorLayer;
30 
31 
40 class GUI_EXPORT QgsFieldExpressionWidget : public QWidget
41 {
42  Q_OBJECT
43  Q_PROPERTY( QString expressionDialogTitle READ expressionDialogTitle WRITE setExpressionDialogTitle )
44  Q_FLAGS( QgsFieldProxyModel::Filters )
45  Q_PROPERTY( QgsFieldProxyModel::Filters filters READ filters WRITE setFilters )
46 
47  public:
51  explicit QgsFieldExpressionWidget( QWidget *parent = nullptr );
52 
54  void setExpressionDialogTitle( const QString& title );
55 
57  const QString expressionDialogTitle() { return mExpressionDialogTitle; }
58 
60  void setFilters( const QgsFieldProxyModel::Filters& filters );
61 
62  void setLeftHandButtonStyle( bool isLeft );
63 
65  QgsFieldProxyModel::Filters filters() const { return mFieldProxyModel->filters(); }
66 
68  void setGeomCalculator( const QgsDistanceArea &da );
69 
75  QString currentField( bool *isExpression = nullptr, bool *isValid = nullptr ) const;
76 
80  bool isValidExpression( QString *expressionError = nullptr ) const;
81 
85  bool isExpression() const;
86 
90  QString currentText() const;
91 
93  QgsVectorLayer* layer() const;
94 
96  typedef QgsExpressionContext( *ExpressionContextCallback )( const void* context );
97 
105  void registerGetExpressionContextCallback( ExpressionContextCallback fnGetExpressionContext, const void* context );
106 
107  signals:
109  void fieldChanged( const QString& fieldName );
110 
112  void fieldChanged( const QString& fieldName, bool isValid );
113 
114 // void returnPressed();
115 
116  public slots:
118  void setLayer( QgsVectorLayer* layer );
119 
121  void setLayer( QgsMapLayer* layer );
122 
124  void setField( const QString &fieldName );
125 
126  protected slots:
128  void editExpression();
129 
131  void expressionEdited( const QString& expression );
132 
134  void expressionEditingFinished();
135 
136  void currentFieldChanged();
137 
143  void updateLineEditStyle( const QString& expression = QString() );
144 
145  bool isExpressionValid( const QString& expressionStr );
146 
147  protected:
148  void changeEvent( QEvent* event ) override;
149 
150  private slots:
151  void reloadLayer();
152 
153  void beforeResetModel();
154  void afterResetModel();
155 
156  private:
157  QComboBox* mCombo;
158  QToolButton* mButton;
159  QgsFieldProxyModel* mFieldProxyModel;
160  QString mExpressionDialogTitle;
162  QScopedPointer< QgsExpressionContext > mExpressionContext;
163  ExpressionContextCallback mExpressionContextCallback;
164  const void* mExpressionContextCallbackContext;
165  QString mBackupExpression;
166 
167  friend class TestQgsFieldExpressionWidget;
168 };
169 
170 #endif // QGSFIELDEXPRESSIONWIDGET_H
The QgsFieldExpressionWidget class reates a widget to choose fields and edit expressions It contains ...
Base class for all map layer types.
Definition: qgsmaplayer.h:49
The QgsFieldProxyModel class provides an easy to use model to display the list of fields of a layer...
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
virtual void changeEvent(QEvent *event)
QgsFieldProxyModel::Filters filters() const
currently used filter on list of fields
General purpose distance and area calculator.
Represents a vector layer which manages a vector based data sets.