Graphics Reference
In-Depth Information
The Delete Track map tool
We now want to implement the
Delete Track
action. Fortunately, the map tool for doing is
very simple, thanks to our mixin class. Add the following class definition to the
mapTools.py
module:
class DeleteTrackTool(QgsMapTool, MapToolMixin):
def __init__(self, canvas, layer, onTrackDeleted):
QgsMapTool.__init__(self, canvas)
self.onTrackDeleted = onTrackDeleted
self.feature = None
self.setLayer(layer)
self.setCursor(Qt.CrossCursor)
def canvasPressEvent(self, event):
self.feature = self.findFeatureAt(event.pos())
def canvasReleaseEvent(self, event):
feature = self.findFeatureAt(event.pos())
if feature != None and feature.id() ==
self.feature.id():
self.layer.deleteFeature(self.feature.id())
self.onTrackDeleted()
Then, back in the
forestTrails.py
module, add the following to the end of the
setupMapTools()
method:
self.deleteTrackTool = DeleteTrackTool(
self.mapCanvas, self.trackLayer,
self.onTrackDeleted)
self.deleteTrackTool.setAction(self.actionDeleteTrack)
Then replace the dummy
deleteTrack()
method with the following:
def deleteTrack(self):
if self.actionDeleteTrack.isChecked():
self.mapCanvas.setMapTool(self.deleteTrackTool)
