I try to run a qgis native algorithm in a qgis plugin and I can't make it work. I follow espescially this answer on a GIS SE question. I will add my whole code at the end of the question, since I do not know where the fault is located at and I'm new to pyqgis.
If I start my plugin I can add a vectorlayer from the layerslist and choose the output destination. Those are supposed to be the input and output of the algorithm. But when I run it I just get an errormessage from QGIS, but the errorlog contains no python errors, even though it says so. So I am stuck at that point. On top of it, after closing QGIS, the desktop shortcut didn't work anymore, because the .exe was not found (it was supposed to be located at C:\OSGeo4W64\bin, but it is not anymore. It seems to be deleted somehow).
Heres the code. At first I import everything, what I think is needed and with the function "IntersectionsToNodes" I try running the algorithm. I use QGIS 3.2.
import os.path
import sys
from PyQt5.QtCore import QSettings, QTranslator, qVersion, QCoreApplication
from PyQt5.QtGui import QIcon
from PyQt5.QtWidgets import QAction, QFileDialog
from qgis.core import *
from qgis.analysis import QgsNativeAlgorithms
#Access the processing algorithm
QgsApplication.setPrefixPath('C:/OSGeo4W64/apps/qgis', True)
qgs = QgsApplication([],False)
qgs.initQgis()
#Folder location of processing plugin
sys.path.append('C:/OSGeo4W64/apps/qgis/python/plugins')
import processing
from processing.core.Processing import Processing
Processing.initialize()
QgsApplication.processingRegistry().addProvider(QgsNativeAlgorithms())
# Initialize Qt resources from file resources.py
# Import the code for the dialog
from .befahrungsplanung_dialog import BefahrungsplanungDialog
class Befahrungsplanung:
"""QGIS Plugin Implementation."""
def __init__(self, iface):
"""Constructor.
:param iface: An interface instance that will be passed to this class
which provides the hook by which you can manipulate the QGIS
application at run time.
:type iface: QgsInterface
"""
# Save reference to the QGIS interface
self.iface = iface
# initialize plugin directory
self.plugin_dir = os.path.dirname(__file__)
# initialize locale
locale = QSettings().value('locale/userLocale')[0:2]
locale_path = os.path.join(
self.plugin_dir,
'i18n',
'Befahrungsplanung_{}.qm'.format(locale))
if os.path.exists(locale_path):
self.translator = QTranslator()
self.translator.load(locale_path)
if qVersion() > '4.3.3':
QCoreApplication.installTranslator(self.translator)
# Create the dialog (after translation) and keep reference
self.dlg = BefahrungsplanungDialog()
# Declare instance attributes
self.actions = []
self.menu = self.tr(u'&Befahrungsplanung')
# TODO: We are going to let the user set this up in a future iteration
self.toolbar = self.iface.addToolBar(u'Befahrungsplanung')
self.toolbar.setObjectName(u'Befahrungsplanung')
self.dlg.directory.clear()
self.dlg.push_directory.clicked.connect(self.output)
self.dlg.button_box.clicked.connect(self.IntersectionsToNodes)
# noinspection PyMethodMayBeStatic
def tr(self, message):
"""Get the translation for a string using Qt translation API.
We implement this ourselves since we do not inherit QObject.
:param message: String for translation.
:type message: str, QString
:returns: Translated version of message.
:rtype: QString
"""
# noinspection PyTypeChecker,PyArgumentList,PyCallByClass
return QCoreApplication.translate('Befahrungsplanung', message)
def add_action(
self,
icon_path,
text,
callback,
enabled_flag=True,
add_to_menu=True,
add_to_toolbar=True,
status_tip=None,
whats_this=None,
parent=None):
"""Add a toolbar icon to the toolbar.
:param icon_path: Path to the icon for this action. Can be a resource
path (e.g. ':/plugins/foo/bar.png') or a normal file system path.
:type icon_path: str
:param text: Text that should be shown in menu items for this action.
:type text: str
:param callback: Function to be called when the action is triggered.
:type callback: function
:param enabled_flag: A flag indicating if the action should be enabled
by default. Defaults to True.
:type enabled_flag: bool
:param add_to_menu: Flag indicating whether the action should also
be added to the menu. Defaults to True.
:type add_to_menu: bool
:param add_to_toolbar: Flag indicating whether the action should also
be added to the toolbar. Defaults to True.
:type add_to_toolbar: bool
:param status_tip: Optional text to show in a popup when mouse pointer
hovers over the action.
:type status_tip: str
:param parent: Parent widget for the new action. Defaults None.
:type parent: QWidget
:param whats_this: Optional text to show in the status bar when the
mouse pointer hovers over the action.
:returns: The action that was created. Note that the action is also
added to self.actions list.
:rtype: QAction
"""
icon = QIcon(icon_path)
action = QAction(icon, text, parent)
action.triggered.connect(callback)
action.setEnabled(enabled_flag)
if status_tip is not None:
action.setStatusTip(status_tip)
if whats_this is not None:
action.setWhatsThis(whats_this)
if add_to_toolbar:
self.toolbar.addAction(action)
if add_to_menu:
self.iface.addPluginToMenu(
self.menu,
action)
self.actions.append(action)
return action
def initGui(self):
"""Create the menu entries and toolbar icons inside the QGIS GUI."""
icon_path = ':/plugins/befahrungsplanung/icon.png'
self.add_action(
icon_path,
text=self.tr(u'Befahrungsplanung'),
callback=self.run,
parent=self.iface.mainWindow())
self.layerlist()
def unload(self):
"""Removes the plugin menu item and icon from QGIS GUI."""
for action in self.actions:
self.iface.removePluginMenu(
self.tr(u'&Befahrungsplanung'),
action)
self.iface.removeToolBarIcon(action)
# remove the toolbar
del self.toolbar
def run(self):
"""Run method that performs all the real work"""
# show the dialog
self.dlg.show()
# Run the dialog event loop
result = self.dlg.exec_()
# See if OK was pressed
if result:
# Do something useful here - delete the line containing pass and
# substitute with your code.
pass
def layerlist(self):
"""Load all linevector layers"""
self.dlg.layerlist.clear()
layers = [layer for layer in QgsProject.instance().mapLayers().values()]
vector_layers = []
for layer in layers:
if layer.type() == QgsMapLayer.VectorLayer and layer.geometryType() == QgsWkbTypes.LineGeometry:
vector_layers.append(layer.name())
self.dlg.layerlist.addItems(vector_layers)
def output(self):
"""Choose Shapefile or Geopackage as Output File"""
filename = str(QFileDialog.getSaveFileName(self.dlg,
"Output Datei auswählen ",
"",
"shapefile (*.shp);;geopackage (*.gpkg)")[0])
self.dlg.directory.setText(filename)
def IntersectionsToNodes(self):
"""Transforms all intersections in the selected layer into nodes"""
layers = self.iface.legendInterface().layers()
inputIndex = self.dlg.layerlist.currentIndex()
input = layers[inputIndex]
filename = self.dlg.directory.text()
output = open(filename, 'w')
params = {
'INPUT' : input,
'LINES' : input,
'OUTPUT' : output
}
res = processing.run('native:splitwithlines', params)
res['OUTPUT']
#processing.algorithmHelp("qgis:splitwithlines")
