PyQGIS standalone script does not work. Error "QGraphicsScene::addItem: item has alre
I try to test a PyQGIS standalone script which should just show one Shapefile.Sounds pretty simple but does not work.
Here is my script:
from PyQt4 import *from PyQt4 import *from PyQt4.QtCore import *from PyQt4.QtGui import *from qgis.core import *from qgis.gui import *from qgis.utils import *import sysimport osqgishome = "C:\OSGeo4W64\apps\qgis"app = QgsApplication([], True)QgsApplication.setPrefixPath(qgishome, True)QgsApplication.initQgis()canvas = QgsMapCanvas()canvas.setCanvasColor(Qt.yellow)canvas.enableAntiAliasing(True)canvas.show()layer = QgsVectorLayer(r"C:/daten/polygons.shp", "Testdaten", "ogr")reg = QgsMapLayerRegistry.instance()reg.addMapLayer(layer)canvas.setExtent(layer.extent())canvas.setLayerSet([QgsMapCanvasLayer(layer)])QgsApplication.exitQgis()app.exec_()app.exitQgis()The Window openes, I can see the yellow background but the Layer is not shown. instad of that there is an error message:
QGraphicsScene::addItem: item has already been added to this sceneQObject::connect: Cannot connect (null)::repaintRequested() to QgsMapCanvas::refresh()QObject::connect: Cannot connect (null)::layerCrsChanged() to QgsMapCanvas::layerCrsChange()Sometimes this also brings python to crash, so that a windows error reporting is opened.
I loaded the neccessary environmental variables, which should be ok, as I can import qgis.core and qgis.gui without problems.
does anyone has an idea what's the problem?
أكثر...
I try to test a PyQGIS standalone script which should just show one Shapefile.Sounds pretty simple but does not work.
Here is my script:
from PyQt4 import *from PyQt4 import *from PyQt4.QtCore import *from PyQt4.QtGui import *from qgis.core import *from qgis.gui import *from qgis.utils import *import sysimport osqgishome = "C:\OSGeo4W64\apps\qgis"app = QgsApplication([], True)QgsApplication.setPrefixPath(qgishome, True)QgsApplication.initQgis()canvas = QgsMapCanvas()canvas.setCanvasColor(Qt.yellow)canvas.enableAntiAliasing(True)canvas.show()layer = QgsVectorLayer(r"C:/daten/polygons.shp", "Testdaten", "ogr")reg = QgsMapLayerRegistry.instance()reg.addMapLayer(layer)canvas.setExtent(layer.extent())canvas.setLayerSet([QgsMapCanvasLayer(layer)])QgsApplication.exitQgis()app.exec_()app.exitQgis()The Window openes, I can see the yellow background but the Layer is not shown. instad of that there is an error message:
QGraphicsScene::addItem: item has already been added to this sceneQObject::connect: Cannot connect (null)::repaintRequested() to QgsMapCanvas::refresh()QObject::connect: Cannot connect (null)::layerCrsChanged() to QgsMapCanvas::layerCrsChange()Sometimes this also brings python to crash, so that a windows error reporting is opened.
I loaded the neccessary environmental variables, which should be ok, as I can import qgis.core and qgis.gui without problems.
does anyone has an idea what's the problem?
أكثر...