class LoginScreen(Screen):def __init__(self,**kwargs):super(LoginScreen, self).__init__(**kwargs)print self,self.parent.currentclass AppScreenManager(ScreenManager):pass#Base Class
class AppBaseClass(App):def build(self):icon='app_icon'return Builder.load_file('appbase.kv')________________________________________________________________________________________________AppScreenManager:transition: FadeTransition()LoginScreen:

Error: AttributeError: 'NoneType' object has no attribute 'current'. Please help.

At the moment you call:

print self,self.parent.current

the LoginScreen is not instantiated yet, so you are calling for and object that does not exist.

The workaround is to delay the call by 1 frame, that can be done using Clock class:

 Clock.schedule_once(self._myprintfunction, 1/60)

and latter in your code but in the same class:

    def _myprintfunction(self, dt):print '-'*25print selfprint self.parent# print self.parent.curet <- this will throw you an error print '-'*25

Hope it helps.