Smarter default edit widgets with plugins to pick them

Now the widgets factories can give a score on how good they could handle
a widget.

Additionaly, plugins can be added to choose a widget factory in function
of an external information. One of them uses a table in PostgresQL to
allow specification of the widget type and configuration.

I took the opportunity to remove a few deprecated method in relation to
this.

Author: Patrick Valsecchi

doc/api_break.dox

@@ -492,6 +492,8 @@ place of a null pointer.</li>
 
 <ul>
 <li>Does no longer inherit QObject
+<li>widgetType() and widgetConfig() now reflect only the user configured values.
+QgsEditorWidgetRegistry::instance()->findBest() must be used instead.</li>
 </ul>
 
 \subsection qgis_api_break_3_0_QgsExpression QgsExpression
@@ -590,6 +592,13 @@ and the new ramp can be retrieved after executing the dialog by calling ramp().<
 plugins calling this method will need to be updated.</li>
 </ul>
 
+\subsection qgis_api_break_3_0_QgsEditorWidgetRegistry QgsEditorWidgetRegistry
+
+<ul>
+<li>The signature of isFieldSupported() has been changed to return an unsigned (how good it supports the given field)
+and to const-correct it.</li>
+</ul>
+
 \subsection qgis_api_break_3_0_QgsGroupWMSDataDialog QgsGroupWMSDataDialog
 
 <ul>
@@ -817,6 +826,14 @@ plugins calling this method will need to be updated.</li>
 
 <ul>
 <li>setMapRenderer() has been removed. Use setMapSettings() instead.</li>
+<li>excludeAttributesWMS() and setExcludeAttributesWMS() have been renamed to excludeAttributesWms() and
+setExcludeAttributesWms()</li>
+<li>excludeAttributesWFS() and setExcludeAttributesWFS() have been renamed to excludeAttributesWfs() and 
+setExcludeAttributesWfs()</li>
+<li>editorWidgetV2() and editorWidgetV2Config() have been removed and QgsEditorWidgetRegistry::instance()->findBest() must be used instead.</li>
+<li>setEditorWidgetV2(), setEditorWidgetV2Config() have been removed and their equivalent in editFormConfig() must be used instead.</li>
+<li>setCheckedState() is removed. Use editFormConfig()->setWidgetConfig()` instead.</li>
+<li>valueMap(), valueRelation(), dateFormat(), widgetSize() have been removed. Use QgsEditorWidgetRegistry::instance()->findBest().config() instead.</li>
 </ul>
 
 \subsection qgis_api_break_3_0_QgsRenderContext QgsRenderContext

python/core/qgseditformconfig.sip

@@ -142,15 +142,6 @@ class QgsEditFormConfig
      */
     void setWidgetType( int fieldIdx, const QString& widgetType );
 
-    /**
-     * Get the id for the editor widget used to represent the field at the given index
-     *
-     * @param fieldIdx  The index of the field
-     *
-     * @return The id for the editor widget or a NULL string if not applicable
-     */
-    QString widgetType( int fieldIdx ) const;
-
     /**
      * Get the id for the editor widget used to represent the field at the given index
      *
@@ -177,40 +168,14 @@ class QgsEditFormConfig
      */
     void setWidgetConfig( int attrIdx, const QgsEditorWidgetConfig& config );
 
-    /**
-     * Set the editor widget config for a widget.
-     *
-     * Example:
-     * \code{.py}
-     *   layer.setWidgetConfig( 'relation_id', { 'nm-rel': 'other_relation' } )
-     * \endcode
-     *
-     * @param widgetName  The name of the widget or field to configure
-     * @param config      The config to set for this field
-     *
-     * @see setWidgetType() for a list of widgets and choose the widget to see the available options.
-     *
-     * @note not available in python bindings
-     */
-    // void setWidgetConfig( const QString& widgetName, const QgsEditorWidgetConfig& config );
-
-    /**
-     * Get the configuration for the editor widget used to represent the field at the given index
-     *
-     * @param fieldIdx  The index of the field
-     *
-     * @return The configuration for the editor widget or an empty config if the field does not exist
-     */
-    QgsEditorWidgetConfig widgetConfig( int fieldIdx ) const;
-
     /**
      * Get the configuration for the editor widget used to represent the field with the given name
      *
-     * @param widgetName The name of the widget. This can be a field name or the name of an additional widget.
+     * @param fieldName The name of the field.
      *
      * @return The configuration for the editor widget or an empty config if the field does not exist
      */
-    QgsEditorWidgetConfig widgetConfig( const QString& widgetName ) const;
+    QgsEditorWidgetConfig widgetConfig( const QString& fieldName ) const;
 
     /**
      * Remove the configuration for the editor widget used to represent the field at the given index
@@ -224,11 +189,11 @@ class QgsEditFormConfig
     /**
      * Remove the configuration for the editor widget used to represent the field with the given name
      *
-     * @param widgetName The name of the widget. This can be a field name or the name of an additional widget.
+     * @param fieldName The name of the field.
      *
      * @return true if successful, false if the field does not exist
      */
-    bool removeWidgetConfig( const QString& widgetName );
+    bool removeWidgetConfig( const QString& fieldName );
 
     /**
      * This returns true if the field is manually set to read only or if the field
@@ -372,4 +337,9 @@ class QgsEditFormConfig
      * Deserialize drag and drop designer elements.
      */
     QgsAttributeEditorElement* attributeEditorElementFromDomElement( QDomElement &elem, QgsAttributeEditorElement* parent );
+
+     /**
+      * Parse the XML for the config of one editor widget.
+      */
+    static QgsEditorWidgetConfig parseEditorWidgetConfig( const QDomElement& cfgElem );
 };

python/core/qgsfield.sip

@@ -1,3 +1,35 @@
+/** \ingroup core
+ * Holder for the widget type and its configuration for a field.
+ */
+class QgsEditorWidgetSetup
+{
+%TypeHeaderCode
+#include <qgsfield.h>
+%End
+  public:
+    /**
+     * Constructor
+     */
+    QgsEditorWidgetSetup( const QString& type, const QgsEditorWidgetConfig& config );
+    QgsEditorWidgetSetup();
+
+    /**
+     * @return the widget type to use
+     */
+    QString type() const;
+
+    /**
+     * @return the widget configuration to used
+     */
+    QgsEditorWidgetConfig config() const;
+
+    /**
+     * @return true if there is no widget configured.
+     */
+    bool isNull() const;
+};
+
+
 /** \class QgsField
   * \ingroup core
   * Encapsulate a field in an attribute table or data source.
@@ -179,6 +211,19 @@ class QgsField
     //! Allows direct construction of QVariants from fields.
     operator QVariant() const;
 
+    /**
+     * Set the editor widget setup for the field.
+     *
+     * @param v  The value to set
+     */
+    void setEditorWidgetSetup( const QgsEditorWidgetSetup& v );
+
+    /**
+     * Get the editor widget setup for the field.
+     *
+     * @return the value
+     */
+    const QgsEditorWidgetSetup& editorWidgetSetup() const;
 }; // class QgsField
 
 

python/gui/editorwidgets/core/qgseditorwidgetautoconf.sip

@@ -0,0 +1,41 @@
+/***************************************************************************
+    qgseditorwidgetautoconf.sip
+    ---------------------
+    begin                : July 2016
+    copyright            : (C) 2016 by Patrick Valsecchi
+    email                : patrick.valsecchi at camptocamp.com
+ ***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+/**
+ * Base class for plugins allowing to pick automatically a widget type for editing fields.
+ *
+ * @note added in QGIS 3.0
+ */
+class QgsEditorWidgetAutoConfPlugin
+{
+  %TypeHeaderCode
+  #include <qgseditorwidgetautoconf.h>
+  %End
+
+  public:
+    /**
+     * Typical scores are:
+     *   * 0: no matching type found.
+     *   * 10: a widget has been guessed from the type of field.
+     *   * 20: a widget has been determined from an external configuration (for example a database table)
+     *
+     * @param vl        The vector layer for which this widget will be created
+     * @param fieldName The field name on the specified layer for which this widget will be created
+     * @param score     Where the score is returned (default to 0)
+     *
+     * @return and integer value rating how good is the setup provided by this plugin.
+     */
+    virtual QgsEditorWidgetSetup editorWidgetSetup( const QgsVectorLayer* vl, const QString& fieldName, int& score /Out/ ) const = 0;
+};

python/gui/editorwidgets/core/qgseditorwidgetfactory.sip

@@ -170,17 +170,23 @@ class QgsEditorWidgetFactory
      */
     virtual QgsEditorWidgetConfig readConfig( const QDomElement& configElement, QgsVectorLayer* layer, int fieldIdx );
 
-  private:
     /**
      * This method allows disabling this editor widget type for a certain field.
-     * By default, it returns true for all fields.
+     * By default, it returns 5 for every fields.
      * Reimplement this if you only support certain fields.
      *
+     * Typical return values are:
+     *   * 0: not supported
+     *   * 5: maybe support (for example, Datetime support strings depending on their content)
+     *   * 10: basic support (this is what returns TextEdit for example, since it supports everything in a crude way)
+     *   * 20: specialised support
+     *
      * @param vl
      * @param fieldIdx
-     * @return True if the field is supported.
+     * @return 0 if the field is not supported or a bigger number if it can (the widget with the biggest number will be
+     *      taken by default). The default implementation returns 5..
      *
      * @see supportsField( QgsVectorLayer* vl, fieldIdx )
      */
-    virtual bool isFieldSupported( QgsVectorLayer* vl, int fieldIdx );
+    virtual unsigned int fieldScore( const QgsVectorLayer* vl, int fieldIdx ) const;
 };

python/gui/editorwidgets/core/qgseditorwidgetregistry.sip

@@ -13,6 +13,7 @@
  *                                                                         *
  ***************************************************************************/
 
+
 /**
  * This class manages all known edit widget factories
  */
@@ -43,6 +44,17 @@ class QgsEditorWidgetRegistry : QObject
      */
     static void initEditors( QgsMapCanvas* mapCanvas = 0, QgsMessageBar* messageBar = 0 );
 
+    /**
+     * Find the best editor widget and its configuration for a given field.
+     *
+     * @param vl        The vector layer for which this widget will be created
+     * @param fieldIdx  The field index on the specified layer for which this widget will be created
+     *
+     * @return The id of the widget type to use and its config
+     */
+    QgsEditorWidgetSetup findBest( const QgsVectorLayer* vl, const QString& fieldName ) const;
+
+
     /**
      * Create an attribute editor widget wrapper of a given type for a given field.
      * The editor may be NULL if you want the widget wrapper to create a default widget.
@@ -116,4 +128,11 @@ class QgsEditorWidgetRegistry : QObject
      * @return true, if successful, false, if the widgetId is already in use or widgetFactory is NULL
      */
     bool registerWidget( const QString& widgetId, QgsEditorWidgetFactory* widgetFactory /Transfer/ );
+
+     /**
+     * Register a new auto-conf plugin.
+     *
+     * @param plugin The plugin (ownership is transfered)
+     */
+    void registerAutoConfPlugin( QgsEditorWidgetAutoConfPlugin* plugin );
 };

python/gui/gui.sip

@@ -260,6 +260,7 @@
 %Include effects/qgspainteffectwidget.sip
 
 %Include editorwidgets/core/qgseditorconfigwidget.sip
+%Include editorwidgets/core/qgseditorwidgetautoconf.sip
 %Include editorwidgets/core/qgseditorwidgetfactory.sip
 %Include editorwidgets/core/qgseditorwidgetregistry.sip
 %Include editorwidgets/core/qgseditorwidgetwrapper.sip

src/app/ogr/qgsvectorlayersaveasdialog.cpp

@@ -249,8 +249,9 @@ void QgsVectorLayerSaveAsDialog::on_mFormatComboBox_currentIndexChanged( int idx
     bool foundFieldThatCanBeExportedAsDisplayedValue = false;
     for ( int i = 0; i < mLayer->fields().size(); ++i )
     {
-      if ( mLayer->editFormConfig().widgetType( i ) != "TextEdit" &&
-           QgsEditorWidgetRegistry::instance()->factory( mLayer->editFormConfig().widgetType( i ) ) )
+      const QgsEditorWidgetSetup setup = QgsEditorWidgetRegistry::instance()->findBest( mLayer, mLayer->fields()[i].name() );
+      if ( setup.type() != "TextEdit" &&
+           QgsEditorWidgetRegistry::instance()->factory( setup.type() ) )
       {
         foundFieldThatCanBeExportedAsDisplayedValue = true;
         break;
@@ -285,10 +286,11 @@ void QgsVectorLayerSaveAsDialog::on_mFormatComboBox_currentIndexChanged( int idx
 
       if ( foundFieldThatCanBeExportedAsDisplayedValue )
       {
+        const QgsEditorWidgetSetup setup = QgsEditorWidgetRegistry::instance()->findBest( mLayer, mLayer->fields()[i].name() );
         QgsEditorWidgetFactory *factory = nullptr;
         if ( flags == Qt::ItemIsEnabled &&
-             mLayer->editFormConfig().widgetType( i ) != "TextEdit" &&
-             ( factory = QgsEditorWidgetRegistry::instance()->factory( mLayer->editFormConfig().widgetType( i ) ) ) )
+             setup.type() != "TextEdit" &&
+             ( factory = QgsEditorWidgetRegistry::instance()->factory( setup.type() ) ) )
         {
           item = new QTableWidgetItem( tr( "Use %1" ).arg( factory->name() ) );
           item->setFlags(( selectAllFields ) ? ( Qt::ItemIsEnabled | Qt::ItemIsUserCheckable ) : Qt::ItemIsUserCheckable );

src/app/qgisapp.cpp

@@ -6149,11 +6149,11 @@ QVariant QgisAppFieldValueConverter::convert( int idx, const QVariant& value )
   {
     return value;
   }
-  QgsEditorWidgetFactory *factory = QgsEditorWidgetRegistry::instance()->factory( mLayer->editFormConfig().widgetType( idx ) );
+  const QgsEditorWidgetSetup setup = QgsEditorWidgetRegistry::instance()->findBest( mLayer, mLayer->fields().field( idx ).name() );
+  QgsEditorWidgetFactory *factory = QgsEditorWidgetRegistry::instance()->factory( setup.type() );
   if ( factory )
   {
-    QgsEditorWidgetConfig cfg( mLayer->editFormConfig().widgetConfig( idx ) );
-    return QVariant( factory->representValue( mLayer, idx, cfg, QVariant(), value ) );
+    return QVariant( factory->representValue( mLayer, idx, setup.config(), QVariant(), value ) );
   }
   return value;
 }

src/app/qgsattributetabledialog.cpp

@@ -391,7 +391,7 @@ void QgsAttributeTableDialog::columnBoxInit()
     if ( idx < 0 )
       continue;
 
-    if ( mLayer->editFormConfig().widgetType( idx ) != "Hidden" )
+    if ( QgsEditorWidgetRegistry::instance()->findBest( mLayer, field.name() ).type() != "Hidden" )
     {
       QIcon icon = mLayer->fields().iconForField( idx );
       QString alias = mLayer->attributeDisplayName( idx );
@@ -527,10 +527,9 @@ void QgsAttributeTableDialog::filterColumnChanged( QObject* filterAction )
   int fldIdx = mLayer->fieldNameIndex( fieldName );
   if ( fldIdx < 0 )
     return;
-  const QString widgetType = mLayer->editFormConfig().widgetType( fldIdx );
-  const QgsEditorWidgetConfig widgetConfig = mLayer->editFormConfig().widgetConfig( fldIdx );
+  const QgsEditorWidgetSetup setup = QgsEditorWidgetRegistry::instance()->findBest( mLayer, fieldName );
   mCurrentSearchWidgetWrapper = QgsEditorWidgetRegistry::instance()->
-                                createSearchWidget( widgetType, mLayer, fldIdx, widgetConfig, mFilterContainer, mEditorContext );
+                                createSearchWidget( setup.type(), mLayer, fldIdx, setup.config(), mFilterContainer, mEditorContext );
   if ( mCurrentSearchWidgetWrapper->applyDirectly() )
   {
     connect( mCurrentSearchWidgetWrapper, SIGNAL( expressionChanged( QString ) ), SLOT( filterQueryChanged( QString ) ) );

src/app/qgsfieldsproperties.cpp

@@ -392,9 +392,9 @@ void QgsFieldsProperties::loadRelations()
       if ( nmrel.fieldPairs().at( 0 ).referencingField() != relation.fieldPairs().at( 0 ).referencingField() )
         nmCombo->addItem( QString( "%1 (%2)" ).arg( nmrel.referencedLayer()->name(), nmrel.fieldPairs().at( 0 ).referencedField() ), nmrel.id() );
 
-      QgsEditorWidgetConfig cfg = mLayer->editFormConfig().widgetConfig( relation.id() );
+      const QgsEditorWidgetSetup setup = QgsEditorWidgetRegistry::instance()->findBest( mLayer, relation.id() );
 
-      QVariant nmrelcfg = cfg.value( "nm-rel" );
+      const QVariant nmrelcfg = setup.config().value( "nm-rel" );
 
       int idx =  nmCombo->findData( nmrelcfg.toString() );
 
@@ -1028,8 +1028,9 @@ QgsFieldsProperties::FieldConfig::FieldConfig( QgsVectorLayer* layer, int idx )
   mNotNull = layer->editFormConfig().notNull( idx );
   mConstraint = layer->editFormConfig().expression( idx );
   mConstraintDescription = layer->editFormConfig().expressionDescription( idx );
-  mEditorWidgetType = layer->editFormConfig().widgetType( idx );
-  mEditorWidgetConfig = layer->editFormConfig().widgetConfig( idx );
+  const QgsEditorWidgetSetup setup = QgsEditorWidgetRegistry::instance()->findBest( layer, layer->fields().field( idx ).name() );
+  mEditorWidgetType = setup.type();
+  mEditorWidgetConfig = setup.config();
 }
 
 /*