Save Vector layer on disk with help of PyQGIS

Question

I have a vector layer, which I ma adding it to a subgroup "streets_greoup". My code also save it to the disk. But it still show temporary layer when I close my project and saved feature data lost. Below is my code.

How can I remove this temporary storage symbol and save data in this layer? Data should not removed after closed project. It should save permanently.

project_dir_path = str(QFileDialog.getExistingDirectory(None,"Select Directory"))

project = QgsProject.instance()
project.write(project_dir_path +"/qgs_design_test.qgs")

root = QgsProject.instance().layerTreeRoot()
master_group = root.addGroup('streets_group')
mygroup = root.findGroup("streets_group")  # We assume the group exists

layer_name = 'terminal'
Fl_ou = project_dir_path + '/' + layer_name + ".shp"
mylayer =  QgsVectorLayer("Point", layer_name, "memory")
QgsProject.instance().addMapLayer(mylayer, False)
mygroup.addLayer(mylayer)

options = QgsVectorFileWriter.SaveVectorOptions()
options.driverName = "ESRI Shapefile"
options.overrideGeometryType = QgsWkbTypes.PointZ
QgsVectorFileWriter.writeAsVectorFormatV2(mylayer, Fl_ou, QgsCoordinateTransformContext(), options)

Answer 1

Using writeAsVectorFormatV2 is like using "Save as.." or "Extract". Therefore, it doesn't change the layer source. You need to set data source of the layer to just saved source. Use the following lines after writeAsVectorFormatV2:

# set data source
mylayer.setDataSource(Fl_ou, mylayer.name(), "ogr")

# refresh layer symbol, removes the memory indicator
iface.layerTreeView().refreshLayerSymbology(mylayer.id())