[FEATURE] Add is_selected and num_selected expressions #3681
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| @@ -2172,7 +2172,7 @@ class TestQgsExpression: public QObject | |||
| QgsExpressionContext context = QgsExpressionContextUtils::createFeatureBasedContext( f, QgsFields() ); | |||
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| QVariantList builderExpected; | |||
| QCOMPARE( QgsExpression( "array()" ).evaluate( &context ), QVariant( ) ); | |||
| QCOMPARE( QgsExpression( "array()" ).evaluate( &context ), QVariant( builderExpected ) ); | |||
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@pvalsecc I assume it's expected that array() returns an emty QVariantList() and not an invalid QVariant()?
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Yes, that would be better.
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wonderful feature... was in my plan since a lot of time, but I haven't to work on. I didn't follow in detail the evolution of QgsExpressionContext, since when the QgsExpressionContext.variable( "layer" ) is available is available? |
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layer_id and layer_name for quite some time. |
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Thanks for this new feature @m-kuhn. Looking forward master availability in osgeo4w Would that sound reasonable to have among the expression functions a list of the layers in the project? There are more and more functions that access layers, but user still needs to type its name or id (instead of simple double-click, as done with fields, values and functions). |
* is_selected() returns if the current feature is selected * num_selected() returns the number of selected features on the current layer * is_selected(layer, feature) returns if the "feature" is selected. "feature" must be on "layer". * num_selected(layer) returns the number of selected features on "layer"
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Here's an idea: copying the list box that shows up when the user selects a field to insert, a list of layers could pop up when the user selects a function that relies on layer names. |
| @@ -312,14 +312,19 @@ static QgsExpression::Node* getNode( const QVariant& value, QgsExpression* paren | |||
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| QgsVectorLayer* getVectorLayer( const QVariant& value, QgsExpression* ) | |||
| { | |||
| QString layerString = value.toString(); | |||
| QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( QgsMapLayerRegistry::instance()->mapLayer( layerString ) ); //search by id first | |||
| QgsVectorLayer* vl = value.value<QgsVectorLayer*>(); | |||
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Is this safe? What if the layer has been deleted?
| "description": "Returns if a feature is selected. If called with no parameters checks the current feature.", | ||
| "arguments": [ | ||
| {"arg":"feature","description":"The feature which should be checked for selection"}, | ||
| {"arg":"layer","description":"The layer (or its id or name) on which the selection will be checked"} |
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Check out the newly introduced array _to_string help - there's a proper way to mark optional arguments in the help so that there are styled correctly
must be on "layer".