class ScreenOne(Screen):
    story = StringProperty('')
    def __init__ (self,**kwargs):

        super (ScreenOne, self).__init__(**kwargs)

        Buttonlayout = GridLayout(orientation='vertical',cols=1, spacing=2, size_hint_y=None)
        Buttonlayout.bind(minimum_height=Buttonlayout.setter('height'))
        for i in range(len(id_ref)):
            btn = Button(text=heading[i], size_hint_y=None, height=80,text_size=(350,None),font_size='12sp')
            btn.bind(on_press=partial(self.changer,id_ref[i]))
            Buttonlayout.add_widget(btn)
        root = ScrollView()
        root.add_widget(Buttonlayout)
        self.add_widget(root)

    def changer(self,*args):
        global current_story
        current_story_id = args[0]
        current_story = id_ref.index(current_story_id)
        self.story = heading[current_story]
        self.manager.current = 'screen2'

class ScreenTwo(Screen):

    def __init__(self,**kwargs):
        super (ScreenTwo,self).__init__(**kwargs)
        self.screenOne = ScreenOne()
        my_box1 = BoxLayout(orientation='vertical')
        L1 = Label(text=self.screenOne.story,font_size='24dp')
        L1.bind(story = L1.setter('text'))
        #self.screenOne.bind(L1.setter('text')= story)
        my_button1 = Button(text="Go to screen 1",size_hint_y=None, size_y=100)
        my_button1.bind(on_press=self.changer)
        my_box1.add_widget(L1)
        my_box1.add_widget(my_button1)
        self.add_widget(my_box1)

    def changer(self,*args):
        self.manager.current = 'screen1'