[v0.4.0] New option to calculate the expression on existing features …

…right before creating an AutoField.

AutoFieldManager.py

@@ -27,6 +27,7 @@
 from PyQt4.QtGui import QApplication
 
 from EventManager import EventManager
+from FieldCalculator import FieldCalculator
 
 class AutoFieldManager( QObject ):
     """ Class in charge of the AutoFields administration. 
@@ -52,9 +53,11 @@ def __init__( self, messageManager, iface, settingsPrefix="/AutoFields", organiz
         self.eventManager.attributesDeletedCheckIfAutoFields.connect( self.checkAndDisableAutoFieldsForLayer )
 
         self.eventManager.setAFM( self )
+
+        self.fieldCalculator = FieldCalculator( self.msg, iface )
 
 
-    def createAutoField( self, layer, fieldName, expression, layer2="", field2="" ):
+    def createAutoField( self, layer, fieldName, expression, layer2="", field2="", calculateOnExisting=True ):
         """ Add AutoField properties to both QSettings and dictAutoFields """    
         if not layer or not type(layer) is QgsVectorLayer:
             self.msg.show( 
@@ -115,7 +118,7 @@ def createAutoField( self, layer, fieldName, expression, layer2="", field2="" ):
             self.msg.show( QApplication.translate( "AutoFieldManager",
                 "[Error] 'expression' variable has not a valid value." ),
                 'warning' )
-            return False
+            return False        
 
         autoFieldId = self.buildAutoFieldId( layer, fieldName )
 
@@ -127,6 +130,11 @@ def createAutoField( self, layer, fieldName, expression, layer2="", field2="" ):
                 'warning' )
             return False
 
+
+        if calculateOnExisting: 
+            self.fieldCalculator.calculate( layer, fieldName, expression )
+
+
         # Create AutoField in dictionary
         if not self.dictAutoFields:
             order = 1
@@ -150,12 +158,12 @@ def createAutoField( self, layer, fieldName, expression, layer2="", field2="" ):
         return autoFieldId
 
 
-    def overwriteAutoField( self, layer, fieldName, expression, layer2="", field2="" ):
+    def overwriteAutoField( self, layer, fieldName, expression, layer2="", field2="", calculateOnExisting=True ):
         """ Logic to overwrite an existing AutoField in both QSettings and dictAutoFields """ 
         autoFieldId = self.buildAutoFieldId( layer, fieldName ) 
         if autoFieldId in self.dictAutoFields:
             self.removeAutoField( autoFieldId )        
-            return self.createAutoField( layer, fieldName, expression, layer2, field2 )
+            return self.createAutoField( layer, fieldName, expression, layer2, field2, calculateOnExisting )
 
         return False
 

AutoFieldsDockWidget.py

@@ -97,6 +97,10 @@ def __init__( self, parent, iface, autoFieldManager, messageManager, language='e
             self.autoFieldManager.settingsPrefix + "/showOnlyEnabledAutoFields",
             True, type=bool )
         self.chkOnlyEnabledAutoFields.setChecked( check )
+        check = settings.value( 
+            self.autoFieldManager.settingsPrefix + "/calculateOnExistingFeatures",
+            True, type=bool )
+        self.chkCalculateOnExisting.setChecked( check )
         self.btnRemoveAutoFields.setEnabled( False )
         self.tblAutoFields.sortItems(0, Qt.AscendingOrder)
         self.populateAutoFieldsTable()
@@ -106,6 +110,7 @@ def __init__( self, parent, iface, autoFieldManager, messageManager, language='e
         self.autoFieldManager.autoFieldDisabled.connect( self.populateAutoFieldsTable )
         self.tblAutoFields.itemSelectionChanged.connect( self.updateRemoveAutoFieldButton )
         self.chkOnlyEnabledAutoFields.toggled.connect( self.saveShowOnlyEnabledPreference )
+        self.chkCalculateOnExisting.toggled.connect( self.saveCalculateOnExistingPreference )        
         self.btnRemoveAutoFields.clicked.connect( self.removeAutoFieldFromTable )
 
         # About Tab
@@ -405,6 +410,7 @@ def doSaveAutoField( self, layer, fieldName, expression ):
         """ Repetitive logic to save or overwrite an AutoField """
         # Check if the field is an AutoField and ask if we should overwrite it
         res = True
+        bCalculateOnExisting = self.chkCalculateOnExisting.isChecked()
         if self.autoFieldManager.isFieldAnAutoField( layer, fieldName ):                                        
             reply = QMessageBox.question( self.iface.mainWindow(), 
                 QApplication.translate( "AutoFieldsDockWidgetPy", "Confirmation" ),
@@ -416,10 +422,10 @@ def doSaveAutoField( self, layer, fieldName, expression ):
                 QMessageBox.Yes | QMessageBox.No, QMessageBox.No )
 
             if reply == QMessageBox.Yes:
-                res = self.autoFieldManager.overwriteAutoField( layer, fieldName, expression )
+                res = self.autoFieldManager.overwriteAutoField( layer, fieldName, expression, calculateOnExisting=bCalculateOnExisting )
 
         else:
-            res = self.autoFieldManager.createAutoField( layer, fieldName, expression )
+            res = self.autoFieldManager.createAutoField( layer, fieldName, expression, calculateOnExisting=bCalculateOnExisting )
 
         if not res: 
             # res will only be False if create/overwriteAutoField return False
@@ -592,7 +598,13 @@ def saveShowOnlyEnabledPreference( self, status ):
         settings = QSettings()
         settings.setValue( self.autoFieldManager.settingsPrefix + "/showOnlyEnabledAutoFields" , status )
         self.populateAutoFieldsTable()
-
+
+
+    def saveCalculateOnExistingPreference( self, status ):
+        """ Saves the preference in QSettings """
+        settings = QSettings()
+        settings.setValue( self.autoFieldManager.settingsPrefix + "/calculateOnExistingFeatures" , status )
+
 
     def openDocumentation( self ):
         """ Open a browser to show documentation page """

FieldCalculator.py

@@ -0,0 +1,94 @@
+# -*- coding:utf-8 -*-
+"""
+/***************************************************************************
+AutoFields
+A QGIS plugin
+Automatic attribute updates when creating or modifying vector features
+                             -------------------
+begin                : 2016-09-08 
+copyright            : (C) 2016 by Germán Carrillo (GeoTux)
+email                : [email protected] 
+Adapted from         : https://github.com/qgis/QGIS/blob/322da8b2cf522bc0d6e5d1ba03f4f0597cdf09d2/python/plugins/processing/algs/qgis/FieldsCalculator.py
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+"""
+
+from qgis.core import ( QgsExpression, QgsExpressionContext,
+    QgsExpressionContextUtils, QgsDistanceArea, QgsProject, QGis, GEO_NONE )
+from PyQt4.QtGui import QApplication
+
+class FieldCalculator():
+    """ Class to perform field calculations on existing features. 
+        Not the core of the plugin, but a helpful option.
+        Adapted from QGIS/python/plugins/processing/algs/qgis/FieldsCalculator.py 
+    """     
+
+    def __init__( self, messageManager, iface ):
+        self.msg = messageManager
+        self.iface = iface
+
+
+    def calculate( self, layer, fieldName, expression ):
+        if ( layer.featureCount() == 0 ):
+            self.msg.show( "[Info] * No existing features on layer " + layer.name() + " to calculate expression.", 'info', True )
+            return
+
+        expression = QgsExpression( expression )
+        if expression.hasParserError():
+            self.msg.show( QApplication.translate( "AutoFields-FieldCalculator", "[Error] (Parsing) " ) + \
+                expression.parserErrorString(), 'critical' )
+            return
+
+        context = QgsExpressionContext()
+        context.appendScope( QgsExpressionContextUtils.globalScope() )
+        context.appendScope( QgsExpressionContextUtils.projectScope() )
+        context.appendScope( QgsExpressionContextUtils.layerScope( layer ) )
+        context.setFields( layer.fields() )
+
+        if expression.needsGeometry():
+            if self.iface:
+                # This block was borrowed from QGIS/python/plugins/processing/algs/qgis/FieldsCalculator.py 
+                da = QgsDistanceArea()
+                da.setSourceCrs( layer.crs().srsid() )
+                da.setEllipsoidalMode( self.iface.mapCanvas().mapSettings().hasCrsTransformEnabled() )
+                da.setEllipsoid( QgsProject.instance().readEntry( 'Measure', '/Ellipsoid', GEO_NONE )[0] )
+                expression.setGeomCalculator( da )
+                if QGis.QGIS_VERSION_INT >= 21400: # Methods added in QGIS 2.14
+                    expression.setDistanceUnits( QgsProject.instance().distanceUnits() ) 
+                    expression.setAreaUnits( QgsProject.instance().areaUnits() )
+
+        expression.prepare( context )
+
+        fieldIndex = layer.fieldNameIndex( fieldName )
+        if fieldIndex == -1:
+            return           
+        field = layer.fields()[fieldIndex]
+
+        dictResults = {}
+        for feature in layer.getFeatures():
+            context.setFeature( feature )
+            result = expression.evaluate( context )
+            if expression.hasEvalError():
+                self.msg.show( QApplication.translate( "AutoFields-FieldCalculator", "[Error] (Evaluating) " ) + \
+                    expression.evalErrorString(), 'critical' )
+                return
+
+            dictResults[feature.id()] = { fieldIndex: field.convertCompatible( result ) }
+
+
+        layer.dataProvider().changeAttributeValues( dictResults )
+
+        self.msg.show( "[Info] * An expression was calculated on existing features of layer " + layer.name() + ", field " + fieldName + ".", 'info', True )
+
+
+
+
+

Ui_AutoFields_dock.ui

@@ -40,9 +40,9 @@
            <property name="geometry">
             <rect>
              <x>0</x>
-             <y>0</y>
+             <y>-383</y>
              <width>288</width>
-             <height>726</height>
+             <height>775</height>
             </rect>
            </property>
            <layout class="QVBoxLayout" name="verticalLayout_2">
@@ -591,6 +591,51 @@
               </layout>
              </widget>
             </item>
+            <item>
+             <spacer name="verticalSpacer_10">
+              <property name="orientation">
+               <enum>Qt::Vertical</enum>
+              </property>
+              <property name="sizeType">
+               <enum>QSizePolicy::Fixed</enum>
+              </property>
+              <property name="sizeHint" stdset="0">
+               <size>
+                <width>20</width>
+                <height>4</height>
+               </size>
+              </property>
+             </spacer>
+            </item>
+            <item>
+             <widget class="QCheckBox" name="chkCalculateOnExisting">
+              <property name="toolTip">
+               <string>If there are features in this layer already, enabling this option calculates the expression on them</string>
+              </property>
+              <property name="text">
+               <string>Calculate expression on existing features</string>
+              </property>
+              <property name="checked">
+               <bool>true</bool>
+              </property>
+             </widget>
+            </item>
+            <item>
+             <spacer name="verticalSpacer_12">
+              <property name="orientation">
+               <enum>Qt::Vertical</enum>
+              </property>
+              <property name="sizeType">
+               <enum>QSizePolicy::Fixed</enum>
+              </property>
+              <property name="sizeHint" stdset="0">
+               <size>
+                <width>20</width>
+                <height>5</height>
+               </size>
+              </property>
+             </spacer>
+            </item>
            </layout>
           </widget>
          </widget>

__init__.py

@@ -26,7 +26,7 @@ def description():
   return "Automatic vector field updates when modifying or creating features"
 
 def version(): 
-  return "Version 0.3.0" 
+  return "Version 0.4.0" 
 
 def qgisMinimumVersion():
   return "2.12"

changelog.txt

@@ -1,4 +1,6 @@
 Changes:
+  [0.4.0] (20160909)
+   - New option to calculate the expression on existing features. 
   [0.3.0] (20160817)
    - Official release!
    - AutoFieldManager: normalize sources from 'Add PostgreSQL layer' and 

i18n/AutoFields.pro

@@ -3,6 +3,7 @@ FORMS = ../Ui_AutoFields_dock.ui \
 
 SOURCES = ../EventManager.py \
           ../AutoFieldManager.py \
-          ../AutoFieldsDockWidget.py
+          ../AutoFieldsDockWidget.py \
+          ../FieldCalculator.py
 
 TRANSLATIONS = AutoFields_es.ts

i18n/AutoFields_es.ts

@@ -70,6 +70,17 @@ Necesitarías exportar los datos a otro formato para agregar AutoFields.</transl
         <translation>, por lo cual no pudo ser removido.</translation>
     </message>
 </context>
+<context>
+    <name>AutoFields-FieldCalculator</name>
+    <message>
+        <source>[Error] (Parsing) </source>
+        <translation>[Error] (Parseando) </translation>
+    </message>
+    <message>
+        <source>[Error] (Evaluating) </source>
+        <translation>[Error] (Evaluando) </translation>
+    </message>
+</context>
 <context>
     <name>AutoFieldsDockWidget</name>
     <message>
@@ -334,6 +345,14 @@ Marcela Suárez&lt;br/&gt;
         <source>Save AutoFields</source>
         <translation>Guardar AutoFields</translation>
     </message>
+    <message>
+        <source>If there are features in this layer already, enabling this option calculates the expression on them</source>
+        <translation>Si ya existen registros en esta capa, habilita esta opción para calcular la expresión sobre ellos.</translation>
+    </message>
+    <message>
+        <source>Calculate expression on existing features</source>
+        <translation>Calcular expresión en registros existentes</translation>
+    </message>
 </context>
 <context>
     <name>AutoFieldsDockWidgetPy</name>

metadata.txt

@@ -1,12 +1,14 @@
 [general]
 name=AutoFields
 description=Automatic attribute updates when creating or modifying vector features
-version=0.3.0
+version=0.4.0
 qgisMinimumVersion=2.12
 category=Vector
 author=Germán Carrillo (GeoTux)
 [email protected]
 changelog=
+  [0.4.0] (20160909)
+   - New option to calculate the expression on existing features. 
   [0.3.0] (20160817)
    - Official release!
    - AutoFieldManager: normalize sources from 'Add PostgreSQL layer' and