QGIS API Documentation  2.15.0-Master (af20121)
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 
97  QString asExpression() const;
98 
100  QgsVectorLayer* layer() const;
101 
103  typedef QgsExpressionContext( *ExpressionContextCallback )( const void* context );
104 
112  void registerGetExpressionContextCallback( ExpressionContextCallback fnGetExpressionContext, const void* context );
113 
114  signals:
116  void fieldChanged( const QString& fieldName );
117 
119  void fieldChanged( const QString& fieldName, bool isValid );
120 
121 // void returnPressed();
122 
123  public slots:
125  void setLayer( QgsVectorLayer* layer );
126 
128  void setLayer( QgsMapLayer* layer );
129 
131  void setRow( int row ) { mCombo->setCurrentIndex( row ); }
132 
134  void setField( const QString &fieldName );
135 
136  protected slots:
138  void editExpression();
139 
141  void expressionEdited( const QString& expression );
142 
144  void expressionEditingFinished();
145 
146  void currentFieldChanged();
147 
153  void updateLineEditStyle( const QString& expression = QString() );
154 
155  bool isExpressionValid( const QString& expressionStr );
156 
157  protected:
158  void changeEvent( QEvent* event ) override;
159 
160  private slots:
161  void reloadLayer();
162 
163  void beforeResetModel();
164  void afterResetModel();
165 
166  private:
167  QComboBox* mCombo;
168  QToolButton* mButton;
169  QgsFieldProxyModel* mFieldProxyModel;
170  QString mExpressionDialogTitle;
172  QScopedPointer< QgsExpressionContext > mExpressionContext;
173  ExpressionContextCallback mExpressionContextCallback;
174  const void* mExpressionContextCallbackContext;
175  QString mBackupExpression;
176 
177  friend class TestQgsFieldExpressionWidget;
178 };
179 
180 #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.
void setRow(int row)
sets the current row in the widget
Represents a vector layer which manages a vector based data sets.