[Kivy] Need to render updated recycler view

[test]

hi! refined the code a little, although output is the same. Tried to make the second RV a dynamic class in a widget and then clear the widget and update it everytime a button is clicked on the left. Kindly advice.

import openpyxl
from kivy.app import App
from kivy.lang import Builder
from kivy.uix.recycleview import RecycleView
from kivy.uix.recycleview.views import RecycleDataViewBehavior
from kivy.uix.label import Label
from kivy.properties import BooleanProperty
from kivy.uix.recycleboxlayout import RecycleBoxLayout
from kivy.uix.behaviors import FocusBehavior
from kivy.uix.recycleview.layout import LayoutSelectionBehavior
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.widget import Widget
from kivy.factory import Factory

Builder.load_string('''


<SelectableLabel>:
	# Draw a background to indicate selection
	canvas.before:
		Color:
			rgba: (.0, 0.5, .1, .3) if self.selected else (0, 0, 0, 1)
		Rectangle:
			pos: self.pos
			size: self.size

<RootWid>:
	orientation: 'vertical'
	ActionBar:
		pos_hint: {'top':1}
		ActionView:
			use_separator: True
			ActionPrevious:
				title: 'StuCheck'
				with_previous: False
			ActionOverflow:
			ActionButton:
				text: 'Populate list'
				on_press: QuestionsList().populate()
			ActionButton:
				text: 'Sort list'
				on_press: root.sort()
			ActionButton:
				text: 'Clear list'
				on_press: root.clear()
			ActionGroup:
				text: 'More'
				ActionButton:
					text: 'Insert new item'
					on_press: root.insert(new_item_input.text)
				ActionButton:
					text: 'Update first item'
					on_press: root.update(update_item_input.text)
				ActionButton:
					text: 'Remove first item'
					on_press: root.remove()
	BoxLayout:
		orientation: 'horizontal'
		RV:
		Middle_c:
			Questions_list:

<Middle_c>:
	orientation: 'horizontal'

<Questions_list@RecycleView>:
	data: [{'text':'123'}]
	viewclass: 'SelectableLabel'
	SelectableRecycleBoxLayout:
		default_size: None, dp(56)
		default_size_hint: 1, None
		size_hint_y: None
		height: self.minimum_height
		orientation: 'vertical'
		multiselect: False
		touch_multiselect: True

<RV>:
	data: self.data
	viewclass: 'SelectableLabel'
	SelectableRecycleBoxLayout:
		default_size: None, dp(56)
		default_size_hint: 1, None
		size_hint_y: None
		height: self.minimum_height
		orientation: 'vertical'
		multiselect: False
		touch_multiselect: True

''')

class RootWid(BoxLayout):
	pass
	

class Middle_c(BoxLayout):

	uq = Factory.Questions_list()

	def update_questions(self, subject):
		uq = Factory.Questions_list()
		self.clear_widgets()
		uq.data = self.populate(subject)
		
	def populate(self, subject):
		wb = openpyxl.load_workbook('sWL.xlsx')
		sheet = wb[subject]
		self.data = []
		for row in range (2, sheet.max_row+1):
			question = sheet.cell(row=row, column=1).value
			self.data.append({'text' : question})
		return self.data	


class RV(RecycleView):
	def __init__(self, **kwargs):
		super(RV, self).__init__(**kwargs)
		subjects = [some list here]
		self.data = []
		for subject in subjects:
			self.data.append({'text':subject})


class SelectableRecycleBoxLayout(FocusBehavior, LayoutSelectionBehavior,
								 RecycleBoxLayout):
	''' Adds selection and focus behaviour to the view. '''

class SelectableLabel(RecycleDataViewBehavior, Label):
	''' Add selection support to the Label '''
	index = None
	selected = BooleanProperty(False)
	selectable = BooleanProperty(True)

	def refresh_view_attrs(self, rv, index, data):
		''' Catch and handle the view changes '''
		self.index = index
		return super(SelectableLabel, self).refresh_view_attrs(
			rv, index, data)


	def on_touch_down(self, touch):
		''' Add selection on touch down '''
		if super(SelectableLabel, self).on_touch_down(touch):
			Middle_c().update_questions(RV().data[self.index]['text'])
			return True
		if self.collide_point(*touch.pos) and self.selectable:
			Middle_c().update_questions(RV().data[self.index]['text'])
			return self.parent.select_with_touch(self.index, touch)

	def apply_selection(self, rv, index, is_selected):
		''' Respond to the selection of items in the view. '''
		self.selected = is_selected
		if is_selected:
			Middle_c().update_questions(RV().data[self.index]['text'])
			print("selection changed to {0}".format(rv.data[index]))
		else:
			print("selection removed for {0}".format(rv.data[index]))


class TestApp(App):
	def build(self):
		return RootWid()

if __name__ == '__main__':
	TestApp().run()