Add generic method to QgsMapLayerFactory to create map layers of

any type

python/core/auto_generated/qgsmaplayerfactory.sip.in

@@ -41,6 +41,16 @@ Returns the map layer type corresponding a ``string`` value.
 Converts a map layer ``type`` to a string value.
 
 .. seealso:: :py:func:`typeFromString`
+%End
+
+    static QgsMapLayer *createLayer( const QString &uri, const QString &name, QgsMapLayerType type,
+                                     const QString &provider = QString(), const QgsCoordinateTransformContext &transformContext = QgsCoordinateTransformContext() ) /Factory/;
+%Docstring
+Creates a map layer, given a ``uri``, ``name``, layer ``type`` and ``provider`` name.
+
+Caller takes ownership of the returned layer.
+
+.. versionadded:: 3.22
 %End
 
 };

src/core/qgsmaplayerfactory.cpp

@@ -16,6 +16,12 @@
  ***************************************************************************/
 
 #include "qgsmaplayerfactory.h"
+#include "qgsvectorlayer.h"
+#include "qgsrasterlayer.h"
+#include "qgsmeshlayer.h"
+#include "qgspointcloudlayer.h"
+#include "qgsvectortilelayer.h"
+#include "qgsannotationlayer.h"
 
 QgsMapLayerType QgsMapLayerFactory::typeFromString( const QString &string, bool &ok )
 {
@@ -60,3 +66,47 @@ QString QgsMapLayerFactory::typeToString( QgsMapLayerType type )
   }
   return QString();
 }
+
+QgsMapLayer *QgsMapLayerFactory::createLayer( const QString &uri, const QString &name, QgsMapLayerType type, const QString &provider, const QgsCoordinateTransformContext &transformContext )
+{
+  switch ( type )
+  {
+    case QgsMapLayerType::VectorLayer:
+    {
+      QgsVectorLayer::LayerOptions options;
+      options.transformContext = transformContext;
+      return new QgsVectorLayer( uri, name, provider, options );
+    }
+
+    case QgsMapLayerType::RasterLayer:
+    {
+      QgsRasterLayer::LayerOptions options;
+      options.transformContext = transformContext;
+      return new QgsRasterLayer( uri, name, provider, options );
+    }
+
+    case QgsMapLayerType::MeshLayer:
+    {
+      QgsMeshLayer::LayerOptions options;
+      options.transformContext = transformContext;
+      return new QgsMeshLayer( uri, name, provider, options );
+    }
+
+    case QgsMapLayerType::VectorTileLayer:
+      return new QgsVectorTileLayer( uri, name );
+
+    case QgsMapLayerType::AnnotationLayer:
+      return new QgsAnnotationLayer( name, QgsAnnotationLayer::LayerOptions( transformContext ) );
+
+    case QgsMapLayerType::PointCloudLayer:
+    {
+      QgsPointCloudLayer::LayerOptions options;
+      options.transformContext = transformContext;
+      return new QgsPointCloudLayer( uri, name, provider, options );
+    }
+
+    case QgsMapLayerType::PluginLayer:
+      break;
+  }
+  return nullptr;
+}

src/core/qgsmaplayerfactory.h

@@ -20,6 +20,7 @@
 
 #include "qgis_core.h"
 #include "qgis.h"
+#include "qgscoordinatetransformcontext.h"
 
 #include <QString>
 
@@ -52,6 +53,16 @@ class CORE_EXPORT QgsMapLayerFactory
      */
     static QString typeToString( QgsMapLayerType type );
 
+    /**
+     * Creates a map layer, given a \a uri, \a name, layer \a type and \a provider name.
+     *
+     * Caller takes ownership of the returned layer.
+     *
+     * \since QGIS 3.22
+     */
+    static QgsMapLayer *createLayer( const QString &uri, const QString &name, QgsMapLayerType type,
+                                     const QString &provider = QString(), const QgsCoordinateTransformContext &transformContext = QgsCoordinateTransformContext() ) SIP_FACTORY;
+
 };
 
 #endif // QGSMAPLAYERFACTORY_H

tests/src/python/test_qgsmaplayerfactory.py

@@ -12,8 +12,21 @@ __copyright__ = 'Copyright 2021, The QGIS Project'
 
 import qgis  # NOQA
 
-from qgis.core import QgsMapLayerFactory, QgsMapLayerType
+import os
+
+from qgis.core import (
+    QgsMapLayerFactory,
+    QgsMapLayerType,
+    QgsVectorLayer,
+    QgsRasterLayer,
+    QgsMeshLayer,
+    QgsPointCloudLayer,
+    QgsAnnotationLayer,
+    QgsVectorTileLayer,
+    QgsDataSourceUri
+)
 from qgis.testing import start_app, unittest
+from utilities import unitTestDataPath
 
 start_app()
 
@@ -62,6 +75,47 @@ class TestQgsMapLayerFactory(unittest.TestCase):
             QgsMapLayerFactory.typeFromString(QgsMapLayerFactory.typeToString(QgsMapLayerType.AnnotationLayer))[0],
             QgsMapLayerType.AnnotationLayer)
 
+    def testCreateLayer(self):
+        # create vector
+        ml = QgsMapLayerFactory.createLayer(os.path.join(unitTestDataPath(), 'lines.shp'), 'lines', QgsMapLayerType.VectorLayer, 'ogr')
+        self.assertTrue(ml.isValid())
+        self.assertIsInstance(ml, QgsVectorLayer)
+        self.assertEqual(ml.name(), 'lines')
+
+        # create raster
+        ml = QgsMapLayerFactory.createLayer(os.path.join(unitTestDataPath(), 'landsat.tif'), 'rl', QgsMapLayerType.RasterLayer, 'gdal')
+        self.assertTrue(ml.isValid())
+        self.assertIsInstance(ml, QgsRasterLayer)
+        self.assertEqual(ml.name(), 'rl')
+
+        # create mesh
+        ml = QgsMapLayerFactory.createLayer(os.path.join(unitTestDataPath(), 'mesh', 'lines.2dm'), 'ml', QgsMapLayerType.MeshLayer, 'mdal')
+        self.assertTrue(ml.isValid())
+        self.assertIsInstance(ml, QgsMeshLayer)
+        self.assertEqual(ml.name(), 'ml')
+
+        # create point cloud
+        ml = QgsMapLayerFactory.createLayer(os.path.join(unitTestDataPath(), 'point_clouds', 'ept', 'rgb', 'ept.json'), 'pcl', QgsMapLayerType.PointCloudLayer, 'ept')
+        self.assertTrue(ml.isValid())
+        self.assertIsInstance(ml, QgsPointCloudLayer)
+        self.assertEqual(ml.name(), 'pcl')
+
+        # annotation layer
+        ml = QgsMapLayerFactory.createLayer('', 'al', QgsMapLayerType.AnnotationLayer)
+        self.assertTrue(ml.isValid())
+        self.assertIsInstance(ml, QgsAnnotationLayer)
+        self.assertEqual(ml.name(), 'al')
+
+        # vector tile layer
+        ds = QgsDataSourceUri()
+        ds.setParam("type", "xyz")
+        ds.setParam("url", "file://{}/{{z}}-{{x}}-{{y}}.pbf".format(os.path.join(unitTestDataPath(), 'vector_tile')))
+        ds.setParam("zmax", "1")
+        ml = QgsMapLayerFactory.createLayer(ds.encodedUri().data().decode(), 'vtl', QgsMapLayerType.VectorTileLayer)
+        self.assertTrue(ml.isValid())
+        self.assertIsInstance(ml, QgsVectorTileLayer)
+        self.assertEqual(ml.name(), 'vtl')
+
 
 if __name__ == '__main__':
     unittest.main()