Совместимость с ранними версиями QGIS

Plugin menu

If you place your plugin menu entries into one of the new menus (Raster, Vector, Database or Web), you should modify the code of the initGui() and unload() functions. Since these new menus are available only in QGIS 2.0 and greater, the first step is to check that the running QGIS version has all the necessary functions. If the new menus are available, we will place our plugin under this menu, otherwise we will use the old Plugins menu. Here is an example for Raster menu

def initGui(self):
  # create action that will start plugin configuration
  self.action = QAction(QIcon(":/plugins/testplug/icon.png"), "Test plugin", self.iface.mainWindow())
  self.action.setWhatsThis("Configuration for test plugin")
  self.action.setStatusTip("This is status tip")
  QObject.connect(self.action, SIGNAL("triggered()"), self.run)

  # check if Raster menu available
  if hasattr(self.iface, "addPluginToRasterMenu"):
    # Raster menu and toolbar available
    self.iface.addRasterToolBarIcon(self.action)
    self.iface.addPluginToRasterMenu("&Test plugins", self.action)
  else:
    # there is no Raster menu, place plugin under Plugins menu as usual
    self.iface.addToolBarIcon(self.action)
    self.iface.addPluginToMenu("&Test plugins", self.action)

  # connect to signal renderComplete which is emitted when canvas rendering is done
  QObject.connect(self.iface.mapCanvas(), SIGNAL("renderComplete(QPainter *)"), self.renderTest)

def unload(self):
  # check if Raster menu available and remove our buttons from appropriate
  # menu and toolbar
  if hasattr(self.iface, "addPluginToRasterMenu"):
    self.iface.removePluginRasterMenu("&Test plugins", self.action)
    self.iface.removeRasterToolBarIcon(self.action)
  else:
    self.iface.removePluginMenu("&Test plugins", self.action)
    self.iface.removeToolBarIcon(self.action)

  # disconnect from signal of the canvas
  QObject.disconnect(self.iface.mapCanvas(), SIGNAL("renderComplete(QPainter *)"), self.renderTest)