time.sleep() doesn't work properly with asynchronous function

Question

I am making a GUI using kivy. It fetches 'static map image' (png) and 'Reverse geo-coded string'(json) from url. For that I am using kivy's builtin asynchronous urlrequest library. My program fetches (latitude, longitude) from a .csv file and shows the picture and address details on screen.Also some internal operations is performed based on the json data (dict)(for ex: how many words there are in address..). There is a ' next ' button, on pressed, next (lat,long) is picked and projected. Now I added an ' automate ' button which will iterate through the (lat,long) and call the exactly same functions when ' next ' is manually pressed, but upon executing, screen freezes, sometimes not responding, if somehow get executed the json data does not get time to refresh.

I am using time.sleep() . But it seems it is of no use. I have searched for it, I don't know whether it is because 'buffer'or not. Bellow is a part of the code:

def automate(self):
    for i in range(5):)
        self.next('NaN')
        time.sleep(6)

Answer 1

You should use the Clock object instead of time.sleep() :

def automate(self):
    Clock.schedule_interval(self.automate_next, 6)

def automate_next(self, dt):
    self.next('NaN')