[FEATURE]: A field calculator, accessible with a button in the attrib…

…ute section of the vector properties

git-svn-id: http://svn.osgeo.org/qgis/trunk@11735 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/app/CMakeLists.txt

@@ -20,6 +20,7 @@ SET(QGIS_APP_SRCS
   qgsspatialitefilterproxymodel.cpp
   qgsspatialitetablemodel.cpp
   qgsdelattrdialog.cpp
+  qgsfieldcalculator.cpp
   qgsnewvectorlayerdialog.cpp
   qgsgraduatedsymboldialog.cpp
   qgshelpviewer.cpp
@@ -122,6 +123,7 @@ SET (QGIS_APP_MOC_HDRS
   qgsconfigureshortcutsdialog.h
   qgscustomprojectiondialog.h
   qgsdelattrdialog.h
+  qgsfieldcalculator.h
   qgsnewvectorlayerdialog.h
   qgsgraduatedsymboldialog.h
   qgshelpviewer.h

src/app/qgsfieldcalculator.cpp

@@ -0,0 +1,353 @@
+/***************************************************************************
+    qgsfieldcalculator.cpp
+    ---------------------
+    begin                : September 2009
+    copyright            : (C) 2009 by Marco Hugentobler
+    email                : marco at hugis dot net
+ ***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsfieldcalculator.h"
+#include "qgssearchtreenode.h"
+#include "qgssearchstring.h"
+#include "qgsvectorlayer.h"
+#include <QMessageBox>
+
+QgsFieldCalculator::QgsFieldCalculator( QgsVectorLayer* vl ): QDialog(), mVectorLayer( vl )
+{
+  setupUi( this );
+  mOutputFieldTypeComboBox->addItem( tr( "Double" ) );
+  mOutputFieldTypeComboBox->addItem( tr( "Integer" ) );
+  mOutputFieldTypeComboBox->addItem( tr( "String" ) );
+
+  populateFields();
+
+  //default values for field width and precision
+  mOuputFieldWidthSpinBox->setValue( 10 );
+  mOutputFieldPrecisionSpinBox->setValue( 3 );
+
+  //disable ok button until there is text for output field and expression
+  mButtonBox->button( QDialogButtonBox::Ok )->setEnabled( false );
+}
+
+QgsFieldCalculator::~QgsFieldCalculator()
+{
+
+}
+
+void QgsFieldCalculator::accept()
+{
+  if ( mVectorLayer && mVectorLayer->isEditable() )
+  {
+    QString calcString = mExpressionTextEdit->toPlainText();
+
+    //create QgsSearchString
+    QgsSearchString searchString;
+    if ( !searchString.setString( calcString ) )
+    {
+      //expression not valid
+      QMessageBox::critical( 0, tr( "Syntax error" ), tr( QString( "Invalid expression syntax. The error message of the parser is: '" + searchString.parserErrorMsg() + "'" ).toLocal8Bit().data() ) );
+      return;
+    }
+
+    //get QgsSearchTreeNode
+    QgsSearchTreeNode* searchTree = searchString.tree();
+    if ( !searchTree )
+    {
+      return;
+    }
+
+    mVectorLayer->beginEditCommand( "Field calculator" );
+
+    //create new field
+    QgsField newField( mOutputFieldNameLineEdit->text() );
+    if ( mOutputFieldTypeComboBox->currentText() == tr( "Double" ) )
+    {
+      newField.setType( QVariant::Double );
+    }
+    else if ( mOutputFieldTypeComboBox->currentText() == tr( "Integer" ) )
+    {
+      newField.setType( QVariant::Int );
+    }
+    else if ( mOutputFieldTypeComboBox->currentText() == tr( "String" ) )
+    {
+      newField.setType( QVariant::String );
+    }
+
+    newField.setLength( mOuputFieldWidthSpinBox->value() );
+    newField.setPrecision( mOutputFieldPrecisionSpinBox->value() );
+
+
+    if ( !mVectorLayer->addAttribute( newField ) )
+    {
+      mVectorLayer->destroyEditCommand();
+      return;
+    }
+
+    //get index of the new field
+    const QgsFieldMap fieldList = mVectorLayer->pendingFields();
+    int attributeId = -1;
+    QgsFieldMap::const_iterator it = fieldList.constBegin();
+    for ( ; it != fieldList.constEnd(); ++it )
+    {
+      if ( it.value().name() == mOutputFieldNameLineEdit->text() )
+      {
+        attributeId = it.key();
+        break;
+      }
+    }
+    if ( attributeId == -1 )
+    {
+      mVectorLayer->destroyEditCommand();
+      return;
+    }
+
+    //go through all the features and change the new attribute
+    QgsFeature feature;
+    bool calculationSuccess = true;
+
+    mVectorLayer->select( mVectorLayer->pendingAllAttributesList(), QgsRectangle(), false, false );
+    while ( mVectorLayer->nextFeature( feature ) )
+    {
+      QgsSearchTreeValue value = searchTree->valueAgainst( mVectorLayer->pendingFields(), feature.attributeMap() );
+      if ( value.isError() )
+      {
+        calculationSuccess = false;
+        break;
+      }
+      if ( value.isNumeric() )
+      {
+        mVectorLayer->changeAttributeValue( feature.id(), attributeId, value.number(), false );
+      }
+      else
+      {
+        mVectorLayer->changeAttributeValue( feature.id(), attributeId, value.string(), false );
+      }
+
+    }
+
+    if ( !calculationSuccess )
+    {
+      QMessageBox::critical( 0, tr( "Error" ), tr( "An error occured while evaluating the calculation string." ) );
+
+      //remove new attribute
+      mVectorLayer->deleteAttribute( attributeId );
+      mVectorLayer->destroyEditCommand();
+      return;
+    }
+
+    mVectorLayer->endEditCommand();
+  }
+  QDialog::accept();
+}
+
+void QgsFieldCalculator::populateFields()
+{
+  if ( !mVectorLayer )
+  {
+    return;
+  }
+
+  const QgsFieldMap fieldMap = mVectorLayer->pendingFields();
+  QgsFieldMap::const_iterator fieldIt = fieldMap.constBegin();
+  for ( ; fieldIt != fieldMap.constEnd(); ++fieldIt )
+  {
+    QString fieldName = fieldIt.value().name();
+    mFieldMap.insert( fieldName, fieldIt.key() );
+    mFieldsListWidget->addItem( fieldName );
+  }
+}
+
+void QgsFieldCalculator::on_mFieldsListWidget_itemDoubleClicked( QListWidgetItem * item )
+{
+  if ( !item )
+  {
+    return;
+  }
+  mExpressionTextEdit->insertPlainText( item->text() );
+}
+
+void QgsFieldCalculator::on_mValueListWidget_itemDoubleClicked( QListWidgetItem * item )
+{
+  if ( !item )
+  {
+    return;
+  }
+  mExpressionTextEdit->insertPlainText( " " + item->text() + " " );
+}
+
+void QgsFieldCalculator::on_mPlusPushButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " + " );
+}
+
+void QgsFieldCalculator::on_mMinusPushButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " - " );
+}
+
+void QgsFieldCalculator::on_mMultiplyPushButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " * " );
+}
+
+void QgsFieldCalculator::on_mDividePushButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " / " );
+}
+
+void QgsFieldCalculator::on_mSqrtButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " sqrt ( " );
+}
+
+void QgsFieldCalculator::on_mExpButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " ^ " );
+}
+
+void QgsFieldCalculator::on_mSinButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " sin ( " );
+}
+
+void QgsFieldCalculator::on_mCosButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " cos ( " );
+}
+
+void QgsFieldCalculator::on_mTanButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " tan ( " );
+}
+
+void QgsFieldCalculator::on_mASinButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " asin ( " );
+}
+
+void QgsFieldCalculator::on_mACosButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " acos ( " );
+}
+
+void QgsFieldCalculator::on_mATanButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " atan ( " );
+}
+
+void QgsFieldCalculator::on_mOpenBracketPushButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " ( " );
+}
+
+void QgsFieldCalculator::on_mCloseBracketPushButton_clicked()
+{
+  mExpressionTextEdit->insertPlainText( " ) " );
+}
+
+void QgsFieldCalculator::on_mSamplePushButton_clicked()
+{
+  getFieldValues( 25 );
+}
+
+void QgsFieldCalculator::on_mAllPushButton_clicked()
+{
+  getFieldValues( 0 );
+}
+
+void QgsFieldCalculator::on_mOutputFieldNameLineEdit_textChanged( const QString& text )
+{
+  setOkButtonState();
+}
+
+void QgsFieldCalculator::on_mExpressionTextEdit_textChanged()
+{
+  setOkButtonState();
+}
+
+void QgsFieldCalculator::on_mOutputFieldTypeComboBox_currentIndexChanged( const QString& text )
+{
+  if ( text == tr( "Double" ) )
+  {
+    mOutputFieldPrecisionSpinBox->setEnabled( true );
+  }
+  else
+  {
+    mOutputFieldPrecisionSpinBox->setEnabled( false );
+  }
+}
+
+void QgsFieldCalculator::getFieldValues( int limit )
+{
+  mValueListWidget->clear();
+
+  if ( !mVectorLayer )
+  {
+    return;
+  }
+
+  QListWidgetItem* currentItem = mFieldsListWidget->currentItem();
+  if ( !currentItem )
+  {
+    return;
+  }
+
+  QMap<QString, int>::const_iterator attIt = mFieldMap.find( currentItem->text() );
+  if ( attIt == mFieldMap.constEnd() )
+  {
+    return;
+  }
+
+  int attributeIndex = attIt.value();
+  QgsField field = mVectorLayer->pendingFields()[attributeIndex];
+  bool numeric = ( field.type() == QVariant::Int || field.type() == QVariant::Double );
+
+  QgsAttributeList attList;
+  attList << attributeIndex;
+
+  mVectorLayer->select( attList, QgsRectangle(), false );
+  QgsFeature f;
+  int resultCounter = 0;
+
+  mValueListWidget->setUpdatesEnabled( false );
+  mValueListWidget->blockSignals( true );
+  QSet<QString> insertedValues;
+
+  while ( mVectorLayer->nextFeature( f ) && ( limit == 0 || resultCounter != limit ) )
+  {
+    QString value = f.attributeMap()[attributeIndex].toString();
+    if ( !numeric )
+    {
+      value = ( "'" + value + "'" );
+    }
+    //QList<QListWidgetItem *> existingItems = mValueListWidget->findItems(value, Qt::MatchExactly);
+    //if(existingItems.isEmpty())
+    if ( !insertedValues.contains( value ) )
+    {
+      mValueListWidget->addItem( value );
+      insertedValues.insert( value );
+      ++resultCounter;
+    }
+  }
+  mValueListWidget->setUpdatesEnabled( true );
+  mValueListWidget->blockSignals( false );
+}
+
+void QgsFieldCalculator::setOkButtonState()
+{
+  bool okEnabled = true;
+  if ( mOutputFieldNameLineEdit->text().isEmpty() || mExpressionTextEdit->toPlainText().isEmpty() )
+  {
+    okEnabled = false;
+  }
+  mButtonBox->button( QDialogButtonBox::Ok )->setEnabled( okEnabled );
+}
+
+