qgis - How to check if plugin icon is toggled?

I've created a plugin icon which can toggle and is connected to the run() function. At the moment, whenever a user clicks on the icon, it executes the run() function.

How could I make it so that it only executes this function when its toggle state isChecked()?

A simple example:

def add_action(self,icon_path,text,callback,checkable=False,enabled_flag=True,add_to_menu=True,add_to_toolbar=True,status_tip=None,whats_this=None,parent=None):

    icon = QIcon(icon_path)
    action = QAction(icon, text, parent)
    action.triggered.connect(callback)
    action.setEnabled(enabled_flag)
    action.setCheckable(checkable)

    if status_tip is not None:
        action.setStatusTip(status_tip)
    if whats_this is not None:
        action.setWhatsThis(whats_this)

    if add_to_toolbar:
        self.toolbar.addAction(action)
    if add_to_menu:
        self.iface.addPluginToMenu(
            self.menu,
            action)

    self.actions.append(action)
    return action


def initGui(self):
    icon_path = ':/plugins/Example/icon.png'
    self.add_action(
        icon_path,
        text=self.tr(u'Example'),
        callback=self.run,
        checkable=True,
        parent=self.iface.mainWindow())

def run(self):

    print 'Plugin loaded.'
    #if checkable == True:
    #   print 'Checked'
    #else:
    #   print 'Unchecked'

Answer

It's a matter of writing a conditional inside the run() function.

QAction.triggered SIGNAL sends the checked state to its connected SLOTs. Add the checked parameter to run() and write a conditional based on that state.

Every button click will still execute the run() function, but you could choose what code you want to be executed for each state.