如何将xml文件拖放到Qtableview中并同时解析xml

Question

I am trying to drag an XML file in QtableView or QtableWidget and parse the file at the same time and display it in different columns in QtableView.

I have gone through many examples but not sure where to begin with , are there any tutorial or example , I need this to be done in PyQt5.

I am doing this for the first time and not sure , how to start this.

one very simple examples of XML file that i have is: each layer name is the first columns and then the subtags are the corresponding properties of the same.

<xtech>
  <Layer id="0" name="EM_UPKG">
    <SourceLayer>NoSource</SourceLayer>
    <Color>
      <R>255</R>
      <G>255</G>
      <B>0</B>
    </Color>
    <Offset>
      <value>114.215</value>
      <dependent>EM_AlN</dependent>
      <placement>Top</placement>
    </Offset>
    <Thickness>
      <value>50</value>
      <dependent>-1</dependent>
    </Thickness>
    <Material>air</Material>
    <Port>NO</Port>
    <Resistivity>0</Resistivity>
    <Transparency>0.8</Transparency>
    <Sheet_Priority>0</Sheet_Priority>
  </Layer>
  <Layer id="1" name="EM_UP">
    <SourceLayer>NoSource</SourceLayer>
    <Color>
      <R>255</R>
      <G>128</G>
      <B>0</B>
    </Color>
    <Offset>
      <value>164.215</value>
      <dependent>EM_UVIA</dependent>
      <placement>Top</placement>
    </Offset>
    <Thickness>
      <value>40</value>
      <dependent>-1</dependent>
    </Thickness>
    <Material>copper</Material>
    <Port>NO</Port>
    <Resistivity>0</Resistivity>
    <Transparency>0</Transparency>
    <Sheet_Priority>0</Sheet_Priority>
  </Layer>
  <Layer id="2" name="EM_UVIA">
    <SourceLayer>NoSource</SourceLayer>
    <Color>
      <R>128</R>
      <G>128</G>
      <B>0</B>
    </Color>
    <Offset>
      <value>114.215</value>
      <dependent>EM_AlN</dependent>
      <placement>Top</placement>
    </Offset>
    <Thickness>
      <value>50</value>
      <dependent>-1</dependent>
    </Thickness>
    <Material>copper</Material>
    <Port>NO</Port>
    <Resistivity>0</Resistivity>
    <Transparency>0</Transparency>
    <Sheet_Priority>0</Sheet_Priority>
  </Layer>
  <Layer id="3" name="EM_PKG">
    <SourceLayer>NoSource</SourceLayer>
    <Color>
      <R>255</R>
      <G>255</G>
      <B>0</B>
    </Color>
    <Offset>
      <value>114.215</value>
      <dependent>EM_AlN</dependent>
      <placement>Top</placement>
    </Offset>
    <Thickness>
      <value>20</value>
      <dependent>-1</dependent>
    </Thickness>
    <Material>air</Material>
    <Port>NO</Port>
    <Resistivity>0</Resistivity>
    <Transparency>0.8</Transparency>
    <Sheet_Priority>0</Sheet_Priority>
  </Layer>
  <Layer id="4" name="EM_PL">
    <SourceLayer>NoSource</SourceLayer>
    <Color>
      <R>255</R>
      <G>128</G>
      <B>0</B>
    </Color>
    <Offset>
      <value>114.215</value>
      <dependent>EM_AlN</dependent>
      <placement>Top</placement>
    </Offset>
    <Thickness>
      <value>95</value>
      <dependent>-1</dependent>
    </Thickness>
    <Material>copper</Material>
    <Port>NO</Port>
    <Resistivity>0</Resistivity>
    <Transparency>0</Transparency>
    <Sheet_Priority>0</Sheet_Priority>
  </Layer>
  <Mesh_Operations>
    <Model_Resolution>60</Model_Resolution>
    <Surface_Approximation>0.5</Surface_Approximation>
  </Mesh_Operations>
  <Port_Processing>
    <Use_Delta>True</Use_Delta>
    <hport_delta>5</hport_delta>
  </Port_Processing>
</xtech>

columns should be displayed as:

TargetLayer, Color, Offset, Thickness, MAterial, Port, Sheet Resistivity, Transparency, Priority and Source Layer

So i wrote the code below to implement drag and drop , now i have to look into how to parse the XML file.

    def __init__(self,parent=None):
    super().__init__()
    self.ui = Ui_MainWindowEtechEditor()
    self.ui.setupUi(self)
    self.setAcceptDrops(True)

    self.ui.pushButton.clicked.connect(self.opecolorEditor)

def opecolorEditor(self):
    color = QColorDialog(self)
    color.setSizeGripEnabled(True)
    color.layout().setSizeConstraint(QLayout.SetNoConstraint)
    color.show()


def dragEnterEvent(self, e):
    if e.mimeData().hasUrls:
        e.accept()
    else:
        e.ignore()

def dragMoveEvent(self, e):
    if e.mimeData().hasUrls:
        e.accept()
    else:
        e.ignore()

def dropEvent(self, e, event=None):
    if e.mimeData().hasUrls():
        e.setDropAction(QtCore.Qt.CopyAction)
        e.accept()

        drop_list = []
        for url in e.mimeData().urls():
            fName = (str(url.toLocalFile()))
            print("path ", fName)

        self.loadExtechfile(fName)

    else:
        e.ignore()

Answer 1

Qt provides QXmlStreamReader , an Xml parser.
The parser reads one element at a time, keeping the current element type and contents, so the only problem is to understand how to keep track of nested elements, as long as the source is well formed.

readNext() returns the element type ("token") of the xml element (which is accessible through tokenType() also).
The most important token types are StartElement and EndElement , you can use QXmlStreamReader.attributes().value(attrName) to read the attributes of a StartElement, and xml.readElementText() for its contents, which might be its text contents or even the raw text of child elements as long as QXmlStreamReader.IncludeChildElements is provided as last argument.

Columns = ('Target Layer', 'Color', 'Offset', 'Thickness', 'Material', 
    'Port', 'Resistivity', 'Transparency', 'Sheet_Priority', 'SourceLayer')
SimpleFields = ('SourceLayer', 'Material', 'Resistivity', 'Port', 
    'Transparency', 'Sheet_Priority')

class Table(QtWidgets.QTableView):
    def __init__(self, *args, **kwargs):
        QtWidgets.QTableView.__init__(self, *args, **kwargs)
        self.setAcceptDrops(True)
        model = QtGui.QStandardItemModel(0, len(Columns))
        model.setHorizontalHeaderLabels(Columns)
        self.setModel(model)

    def dragEnterEvent(self, e):
        # be careful, as you forgot the parenthesis of hasUrls()!
        if e.mimeData().hasUrls() and any(u.isLocalFile() for u in e.mimeData().urls()):
            e.accept()
        else:
            e.ignore()

# ...

    def dropEvent(self, e):
        f = QtCore.QFile(e.mimeData().urls()[0].toLocalFile())
        if not f.open(f.ReadOnly):
            return
        xml = QtCore.QXmlStreamReader(f)
        valid = False
        currentLayer = None
        while not xml.atEnd():
            if xml.readNext() == xml.StartElement:
                # track the first start element and ensure that it's of
                # the right type, otherwise ignore the file
                if not valid:
                    if xml.name() != 'xtech':
                        break
                    valid = True
                    continue
                if xml.name() == 'Layer':
                    # if a currentLayer exists, we assume it's finished,
                    # so we can process it and add its items
                    if currentLayer:
                        self.addLayer(currentLayer)
                    currentLayer = {'Target Layer': xml.attributes().value('name')}
                elif xml.name() in SimpleFields:
                    currentLayer[xml.name()] = xml.readElementText()
                elif xml.name() == 'Color':
                    currentLayer['Color'] = color = QtGui.QColor()
                    # this is a "nested" field, read its contents until
                    # it's reached the end element;
                    while xml.readNext():
                        if xml.tokenType() == xml.EndElement and xml.name() == 'Color':
                            break
                        elif xml.name() == 'R':
                            color.setRed(int(xml.readElementText()))
                        elif xml.name() == 'G':
                            color.setGreen(int(xml.readElementText()))
                        elif xml.name() == 'B':
                            color.setBlue(int(xml.readElementText()))
                # use the same logic for all other nested fields.
        f.close()

    def addLayer(self, layer):
        # create an empty "row" that can be filled with items in the correct
        # order, and that will leave empty cells if some fields do not exist
        row = [None] * len(Columns)
        for field, value in layer.items():
            item = QtGui.QStandardItem()
            if isinstance(value, QtGui.QColor):
                item.setBackground(value)
            else:
                item.setData(value, QtCore.Qt.DisplayRole)
            row[Columns.index(field)] = item
        self.model().appendRow(row)

Some care is necessary about letter cases when parsing elements, you should probably use xml.name().lower() for comparisons against field names.

Answer 2

After struglling for few hours i found another parser xml.etree.ElementTree and implemented the parser code like below which works like a charm.

    def loadExtechfile(self,fName):
    print("load file from  ", fName)
    tree = ET.parse(fName)
    root = tree.getroot()

    for layer in root.findall('Layer'):
        layerName =layer.get('name')
        sourceLayer = layer.find('SourceLayer').text

        for color in layer.findall('Color'):
            r = color.find('R').text
            g = color.find('G').text
            b = color.find('B').text

        combinedRGB = r+","+g+","+b

        for offset in layer.findall('Offset'):
            value = offset.find('value').text
            dep = offset.find('dependent').text
            plc = offset.find('placement').text

        if dep == "-1" and plc == "None":
            combinedOffset = value
        else:
            combinedOffset = value + "(= " + dep + " [" + plc + "])"

        for thickness in layer.findall('Thickness'):
            valueT = thickness.find('value').text
            depT = thickness.find('dependent').text

        if depT != "-1":
            combinedThickness = valueT + "(=" + depT + ")"
        else:
            combinedThickness = valueT
        material = layer.find('Material').text
        port = layer.find('Port').text
        res = layer.find('Resistivity').text
        trans = layer.find('Transparency').text
        sheetPrio = layer.find('Sheet_Priority').text
        #print(layerName,r,g,b,sourceLayer,material,port,res,trans,sheetPrio)