class Homepage(Screen):
    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        self.t = None # used to hold thread

    def on_enter(self,*args):
        if self.t:  # only allow 1 thread to be created
            return
        self.t =threading.Thread(target=self.fetch_data)
        self.t.start()

    def fetch_data(self):
        time.sleep(1)
        try:
        #self.ids.screen_man.current = 'showdata'
        # getting data from real-time database
            self.firebase = firebase.FirebaseApplication('https://lexconnectionsapp-default-rtdb.firebaseio.com/', None)

            self.result = self.firebase.get('lexconnectionsapp-default-rtdb/products', None)
            # data i fetched from my database
            self.data = self.result
            products = [item for item in self.data.values()]  # ignore primary key, get the inner dicts
            for product in products:
                sc = ShowCard(**product)  # same as Showcard(description=product['description'],...)
                self.ids.prduct_grid.add_widget(sc)
        except Exception as error:

            print (str(error))


           # toast(str(error) )