python - Odd behavior in a QGIS plugin: my function is triggered twice

I have a plugin with a function (triggered by a button) that selects a specific layer by name, then shows its attribute table. When I close the plugin and open it again, the attribute table pops up twice, and repeating this keeps adding another table popup. What's wrong?

Code:

def showTable(self):
    for lyrs in QgsMapLayerRegistry.instance().mapLayers().values():

        if lyrs.name() == "TestFeatures":
            lyrTest = lyrs
    self.iface.showAttributeTable(lyrTest)

Answer

You are probably setting a connection between a SIGNAL (button clicked) and a SLOT (your method showTable) every time your plugin is open (run() method?) and you are not disconnecting such SIGNAL/SLOT when your plugin is closed. This leads to a new call to showTable() every time you open your plugin, because there's a new connection calling it.

A couple of solutions for this problem are to:

• Disconnect your SIGNAL/SLOT when closing the plugin; or (recommended)


• Set your connection only in the initGui() method of your plugin, this way a new connection won't be set when opening your plugin, but only when initializing QGIS (or reloading the whole plugin).