Question

我正在使用pyqt5制作一个Qgis 3.4插件，该插件应该加载成对的图层并缩放到选定的图层，但是代码执行得太快，并且在将图层加载到Qgis中之前通过了缩放线。

代码如下：

def openFileNameDialog(self):

    options = QFileDialog.Options()
    options |= QFileDialog.DontUseNativeDialog
    fileName, _ = QFileDialog.getOpenFileName(self,"QFileDialog.getOpenFileName()", "","All Files (*);;Shapefile's (*.shp)", options=options)
    if fileName:
        shape_name = fileName

    shapelayer = QgsVectorLayer(shape_name, "project's shapefile", "ogr")
    if not shapelayer:
      self.statusBar().showMessage('shapefile is invalid')

    else:


        urlWithParams = 'url=urltoBaseMap'

        rlayer = QgsRasterLayer(urlWithParams, 'BaseMap', 'wms')

        if not rlayer.isValid():
            self.statusBar().showMessage('Layer failed to load!')

        QgsProject.instance().addMapLayer(rlayer)
        QgsProject.instance().addMapLayer(shapelayer)

        self.iface.setActiveLayer(shapelayer)

def layerzoom(self):

    self.iface.zoomToActiveLayer()

def runboth(self):

    self.openFileNameDialog()
    #time.sleep(5)
    self.layerzoom()

在加载图层的函数完成图层的加载之后，如何调用缩放函数？

我已经尝试过time.sleep（）了，但是它不等待openFileNameFialog（）完成，所以问题仍然存在。

Answer 1

在代码中添加这两行代码，就可以等待图层加载到zoomIn，这要归功于eyllanesc和ekhumoro的指导

def stop_signal():  self.layeropen()
self.iface.mapCanvas().renderComplete.connect(stop_signal)

代码如下：

def openFileNameDialog(self):

    options = QFileDialog.Options()
    options |= QFileDialog.DontUseNativeDialog
    fileName, _ = QFileDialog.getOpenFileName(self,"QFileDialog.getOpenFileName()", "","All Files (*);;Shapefile's (*.shp)", options=options)
    if fileName:
        shape_name = fileName

    shapelayer = QgsVectorLayer(shape_name, "project's shapefile", "ogr")
    if not shapelayer:
      self.statusBar().showMessage('shapefile is invalid')

    else:


        urlWithParams = 'url=urltoBaseMap'

        rlayer = QgsRasterLayer(urlWithParams, 'BaseMap', 'wms')

        if not rlayer.isValid():
            self.statusBar().showMessage('Layer failed to load!')
        def stop_signal():  
            self.layeropen()
            self.istft = 'yes'

        QgsProject.instance().addMapLayer(rlayer)
        QgsProject.instance().addMapLayer(shapelayer)

        self.iface.mapCanvas().renderComplete.connect(stop_signal)

def layerzoom(self):
    if self.istft == 'yes':
        self.iface.zoomToActiveLayer()
    if self.istft != 'yes':
        pass

def mainprocess(self):

    self.istft = None

在加载图层的函数最终加载图层之后，我该如何调用函数？

1 个答案: