Python core.QgsLayerDefinition类代码示例

    def load_qlr_file(self, path):
        # Load qlr into a group owned by us
        try:
            group = QgsLayerTreeGroup()

            # On Windows this locks the parent dirs indefinitely
            # See http://hub.qgis.org/issues/14811
            # QgsLayerDefinition.loadLayerDefinition(path, group)

            # Instead handle file ourselves
            f = QFile(path)
            if not f.open(QIODevice.ReadOnly):
                return False
            try:
                doc = QDomDocument()
                if not doc.setContent( f.readAll() ):
                    return False
                QgsLayerDefinition.loadLayerDefinition(doc, group)
            finally:
                f.close()

            # Get subtree of nodes
            nodes = group.children()
            # plain list of nodes
            nodeslist = []
            for addedNode in nodes:
                internalid = self._random_string()
                nodeinfo = {'internalid': internalid}
                addedNode.setCustomProperty(QlrManager.customPropertyName, internalid)
                if isinstance(addedNode, QgsLayerTreeGroup):
                    nodeinfo['type'] = 'group'
                    nodeinfo['name'] = addedNode.name()
                elif isinstance(addedNode, QgsLayerTreeLayer):
                    nodeinfo['type'] = 'layer'
                    nodeinfo['name'] = addedNode.layerName()
                    nodeinfo['layerid'] = addedNode.layerId()
                nodeslist.append(nodeinfo)
                # Remove from parent node. Otherwise we cant add it to a new parent
                group.takeChild(addedNode)
            self.fileSystemItemToLegendNode[path] = nodeslist

            # Insert them into the main project
            QgsProject.instance().layerTreeRoot().insertChildNodes(0, nodes)
            return True
        except:
            # For now just return silently
            return False

    def testVectorAndRaster(self):
        # Load a simple QLR containing a vector layer and a raster layer.
        QgsProject.instance().removeAllMapLayers()
        layers = QgsProject.instance().mapLayers()
        self.assertEqual(len(layers), 0)

        (result, errMsg) = QgsLayerDefinition.loadLayerDefinition(TEST_DATA_DIR + '/vector_and_raster.qlr', QgsProject.instance(), QgsProject.instance().layerTreeRoot())
        self.assertTrue(result)

        layers = QgsProject.instance().mapLayers()
        self.assertEqual(len(layers), 2)
        QgsProject.instance().removeAllMapLayers()

    def testInvalidSource(self):
        # Load a QLR containing a vector layer with a broken path
        QgsProject.instance().removeAllMapLayers()
        layers = QgsProject.instance().mapLayers()
        self.assertEqual(len(layers), 0)

        (result, errMsg) = QgsLayerDefinition.loadLayerDefinition(TEST_DATA_DIR + '/invalid_source.qlr', QgsProject.instance(), QgsProject.instance().layerTreeRoot())
        self.assertTrue(result)
        self.assertFalse(errMsg)

        layers = QgsProject.instance().mapLayers()
        self.assertEqual(len(layers), 1)
        self.assertFalse(list(layers.values())[0].isValid())
        QgsProject.instance().removeAllMapLayers()

    def test_layerDefinitionRewriteId(self):
        tmpfile = os.path.join(tempfile.tempdir, "test.qlr")

        ltr = QgsProject.instance().layerTreeRoot()

        self.pointsLayer.setDependencies([QgsMapLayerDependency(self.linesLayer.id())])

        QgsLayerDefinition.exportLayerDefinition(tmpfile, [ltr])

        grp = ltr.addGroup("imported")
        QgsLayerDefinition.loadLayerDefinition(tmpfile, grp)

        newPointsLayer = None
        newLinesLayer = None
        for l in grp.findLayers():
            if l.layerId().startswith('points'):
                newPointsLayer = l.layer()
            elif l.layerId().startswith('lines'):
                newLinesLayer = l.layer()
        self.assertFalse(newPointsLayer is None)
        self.assertFalse(newLinesLayer is None)
        self.assertTrue(newLinesLayer.id() in [dep.layerId() for dep in newPointsLayer.dependencies()])

        self.pointsLayer.setDependencies([])

    def testSaveFields(self):
        # Create a new py layerwith no fields
        myPyLayer = QgsVectorLayer(
            ('Point?crs=epsg:4326&index=yes'),
            'test',
            'pythonprovider')

        # Add some fields to the layer
        myFields = [QgsField('TestInt', QVariant.Int, 'integer', 2, 0),
                    QgsField('TestLong', QVariant.LongLong, 'long', -1, 0),
                    QgsField('TestDbl', QVariant.Double, 'double', 8, 6),
                    QgsField('TestString', QVariant.String, 'string', 50, 0),
                    QgsField('TestDate', QVariant.Date, 'date'),
                    QgsField('TestTime', QVariant.Time, 'time'),
                    QgsField('TestDateTime', QVariant.DateTime, 'datetime')]
        assert myPyLayer.startEditing()
        for f in myFields:
            assert myPyLayer.addAttribute(f)
        assert myPyLayer.commitChanges()
        myPyLayer.updateFields()

        # Export the layer to a layer-definition-XML
        qlr = QgsLayerDefinition.exportLayerDefinitionLayers([myPyLayer], QgsReadWriteContext())
        assert qlr is not None

        # Import the layer from the layer-definition-XML
        layers = QgsLayerDefinition.loadLayerDefinitionLayers(qlr, QgsReadWriteContext())
        assert layers is not None
        myImportedLayer = layers[0]
        assert myImportedLayer is not None

        # Check for the presence of the fields
        importedFields = myImportedLayer.fields()
        assert importedFields is not None
        for f in myFields:
            assert f == importedFields.field(f.name())