handle null

qgis · Feb 21, 2022 · 5850003 · 5850003
1 parent 3372009
commit 5850003
Showing 1 changed file with 4 additions and 2 deletions.
diff --git a/src/core/symbology/qgsrulebasedrenderer.cpp b/src/core/symbology/qgsrulebasedrenderer.cpp
@@ -1202,15 +1202,17 @@ void QgsRuleBasedRenderer::refineRuleCategories( QgsRuleBasedRenderer::Rule *ini
   {
     QString value;
     // not quoting numbers saves a type cast
-    if ( cat.value().type() == QVariant::Int )
+    if ( cat.value().isNull() )
+      value = "NULL";
+    else if ( cat.value().type() == QVariant::Int )
       value = cat.value().toString();
     else if ( cat.value().type() == QVariant::Double )
       // we loose precision here - so we may miss some categories :-(
       // TODO: have a possibility to construct expressions directly as a parse tree to avoid loss of precision
       value = QString::number( cat.value().toDouble(), 'f', 4 );
     else
       value = QgsExpression::quotedString( cat.value().toString() );
-    const QString filter = QStringLiteral( "%1 = %2" ).arg( attr, value );
+    const QString filter = QStringLiteral( "%1 %2 %3" ).arg( attr, value == "NULL" ? "IS" : "=" , value );
     const QString label = !cat.label().isEmpty() ? cat.label() :
                           cat.value().isValid() ? value : QString();
     initialRule->appendChild( new Rule( cat.symbol()->clone(), 0, 0, filter, label ) );