QGIS API Documentation  3.17.0-Master (df2c9ff931)
qgsfieldmappingmodel.h
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1 /***************************************************************************
2  qgsfieldmappingmodel.h - QgsFieldMappingModel
3 
4  ---------------------
5  begin : 17.3.2020
6  copyright : (C) 2020 by Alessandro Pasotti
7  email : elpaso at itopen dot it
8  ***************************************************************************
9  * *
10  * This program is free software; you can redistribute it and/or modify *
11  * it under the terms of the GNU General Public License as published by *
12  * the Free Software Foundation; either version 2 of the License, or *
13  * (at your option) any later version. *
14  * *
15  ***************************************************************************/
16 #ifndef QGSFIELDMAPPINGMODEL_H
17 #define QGSFIELDMAPPINGMODEL_H
18 
19 #include <QAbstractTableModel>
20 #include <QStyledItemDelegate>
21 
22 #include "qgsfields.h"
24 #include "qgsfieldconstraints.h"
25 #include "qgsproperty.h"
26 #include "qgis_gui.h"
27 
28 
39 class GUI_EXPORT QgsFieldMappingModel: public QAbstractTableModel
40 {
41 
42  Q_OBJECT
43 
44  public:
45 
49  enum class ColumnDataIndex : int
50  {
51  SourceExpression,
52  DestinationName,
53  DestinationType,
54  DestinationLength,
55  DestinationPrecision,
56  DestinationConstraints,
57  };
58 
59  Q_ENUM( ColumnDataIndex );
60 
64  struct Field
65  {
67  QString originalName;
71  QString expression;
72  };
73 
81  QgsFieldMappingModel( const QgsFields &sourceFields = QgsFields(),
82  const QgsFields &destinationFields = QgsFields(),
83  const QMap<QString, QString> &expressions = QMap<QString, QString>(),
84  QObject *parent = nullptr );
85 
87  bool destinationEditable() const;
88 
90  void setDestinationEditable( bool editable );
91 
93  static const QMap<QVariant::Type, QString> dataTypes();
94 
96  QgsFields sourceFields() const;
97 
99  QList<QgsFieldMappingModel::Field> mapping() const;
100 
107  QMap< QString, QgsProperty > fieldPropertyMap() const;
108 
114  void setFieldPropertyMap( const QMap< QString, QgsProperty > &map );
115 
117  void appendField( const QgsField &field, const QString &expression = QString() );
118 
120  bool removeField( const QModelIndex &index );
121 
123  bool moveUp( const QModelIndex &index );
124 
126  bool moveDown( const QModelIndex &index );
127 
129  void setSourceFields( const QgsFields &sourceFields );
130 
132  QgsExpressionContextGenerator *contextGenerator() const;
133 
138  void setBaseExpressionContextGenerator( const QgsExpressionContextGenerator *generator );
139 
145  void setDestinationFields( const QgsFields &destinationFields,
146  const QMap<QString, QString> &expressions = QMap<QString, QString>() );
147 
148  // QAbstractItemModel interface
149  int rowCount( const QModelIndex &parent = QModelIndex() ) const override;
150  int columnCount( const QModelIndex &parent = QModelIndex() ) const override;
151  QVariant data( const QModelIndex &index, int role ) const override;
152  QVariant headerData( int section, Qt::Orientation orientation, int role ) const override;
153  Qt::ItemFlags flags( const QModelIndex &index ) const override;
154  bool setData( const QModelIndex &index, const QVariant &value, int role ) override;
155 
156  private:
157 
158  class ExpressionContextGenerator: public QgsExpressionContextGenerator
159  {
160 
161  public:
162 
163  ExpressionContextGenerator( const QgsFields &sourceFields );
164 
165  // QgsExpressionContextGenerator interface
166  QgsExpressionContext createExpressionContext() const override;
167  void setBaseExpressionContextGenerator( const QgsExpressionContextGenerator *generator );
168  void setSourceFields( const QgsFields &fields );
169 
170  private:
171 
172  const QgsExpressionContextGenerator *mBaseGenerator = nullptr;
173 
174  QgsFields mSourceFields;
175 
176  };
177 
178 
179  QgsFieldConstraints::Constraints fieldConstraints( const QgsField &field ) const;
180 
181  bool moveUpOrDown( const QModelIndex &index, bool up = true );
182 
192  QString findExpressionForDestinationField( const QgsFieldMappingModel::Field &field, QStringList &excludedFieldNames );
193 
194  QList<Field> mMapping;
195  bool mDestinationEditable = false;
196  QgsFields mSourceFields;
197  std::unique_ptr<ExpressionContextGenerator> mExpressionContextGenerator;
198 
200 
201 };
202 
203 
204 
205 #endif // QGSFIELDMAPPINGMODEL_H
The QgsAggregateMappingModel holds mapping information for defining sets of aggregates of fields from...
Container of fields for a vector layer.
Definition: qgsfields.h:44
QString originalName
The original name of the field.
Expression contexts are used to encapsulate the parameters around which a QgsExpression should be eva...
QgsField field
The field in its current status (it might have been renamed)
Encapsulate a field in an attribute table or data source.
Definition: qgsfield.h:49
Abstract interface for generating an expression context.
ColumnDataIndex
The ColumnDataIndex enum represents the column index for the view.
QString expression
The expression for the mapped field from the source fields.
The QgsFieldMappingModel holds mapping information for mapping from one set of QgsFields to another...
The Field struct holds information about a mapped field.
const QgsField & field
Definition: qgsfield.h:471