Le portail francophone de la géomatique

from qgis.core import (
    QgsProject, QgsVectorLayer, QgsSymbol, QgsSimpleFillSymbolLayer,
    QgsRendererCategory, QgsCategorizedSymbolRenderer, QgsSvgMarkerSymbolLayer,
    QgsLineSymbol
)
from PyQt5.QtWidgets import QFileDialog


from .resources_rc2 import *  # mon fichier compilé qui contient les symboles svg
...
def open(self):
        filter = "geojson (*.geojson)"
        fileName, _ = QFileDialog.getOpenFileName(None, "geojson", "", filter)
        if fileName:
            print(fileName)

            vlayer = QgsVectorLayer(fileName, "myLayer", "ogr")
            print(vlayer.geometryType())
            if not vlayer.isValid():
                print("Layer failed to load!")
            else:
                QgsProject.instance().addMapLayer(vlayer)
                fni = vlayer.fields().indexFromName('code')
                unique_values = vlayer.uniqueValues(fni)

                categories = []
                for unique_value in unique_values:
                    # initialize the default symbol for this geometry type
                    symbol = QgsSymbol.defaultSymbol(vlayer.geometryType())

                    # configure a symbol layer
                    if unique_value == 'Cable':
                        svgStyle = {}
                        svgStyle['name'] = ':/resources/symbols/line/CBLSUB06.svg'
                        svgStyle['size'] = '12'
                        symbol_layer = QgsSvgMarkerSymbolLayer.create(svgStyle)
                    else:
                        layer_style = {}
                        layer_style['color'] = '%d, %d, %d' % (randrange(0, 256), randrange(0, 256), randrange(0, 256))
                        symbol_layer = QgsSimpleFillSymbolLayer.create(layer_style)

                    # replace default symbol layer with the configured one
                    if symbol_layer is not None:
                        symbol.changeSymbolLayer(0, symbol_layer)

                    # create renderer object
                    category = QgsRendererCategory(unique_value, symbol, str(unique_value))
                    # entry for the list of category items
                    categories.append(category)

                    # create renderer object
                    renderer = QgsCategorizedSymbolRenderer('code', categories)

                    # assign the created renderer to the layer
                    if renderer is not None:
                        vlayer.setRenderer(renderer)

                    vlayer.triggerRepaint()