title: User text not showing after trying to access it in MDTextField (KivyMD)
body: <p>After creating a MDTextField in a MDDialog with KivyMD, I am trying to access the text entered by the user in the MDTextField and change a label's text to whatever was entered but to no avail. Here is my code below:</p>
  <pre><code># importing all the necessary modules and inheriting my dialog from boxlayout
  
  from kivymd.app import MDApp
  from kivy.lang import Builder
  from kivy.uix.boxlayout import BoxLayout   
  from kivymd.uix.dialog import MDDialog     
  
  # creating a string which will contain all my kv definitions that I would put in a .kv file
  
  the_kv_file = '''
  &lt;ContentOfAppointmentDialog&gt;:
      orientation: &quot;vertical&quot;
      spacing: &quot;10dp&quot;
      size_hint: None, None
      size: &quot;250dp&quot;, &quot;150dp&quot;
  
      MDTextField:
          hint_text: &quot;Enter details&quot;
          id: the_textfield
          helper_text: &quot;Be detailed and precise&quot;
          helper_text_mode: &quot;on_focus&quot;
          max_text_length: 75
          multiline: True
          mode: &quot;rectangle&quot;
  
      MDFlatButton:
          text: &quot;DISCARD&quot;
          on_release: app.CloseDialog()
      MDFlatButton:
          text: &quot;DONE&quot;
          on_release: app.ChangingLabel()
  
  MDFloatLayout:
     MDLabel:
         id: label_to_change
         text: &quot;hello&quot;
     MDFloatingActionButton:
         icon: 'pencil'
         on_press: app.OpenDialog()  
  '''
  # Creating the classes of My main app and the dialog as well as the required functions
  
  class ContentOfAppointmentDialog(BoxLayout):    # this defines the dialogs layout
      pass
  
  
  class MainApp(MDApp):   # my main app
      def build(self):
          self.main_screen = Builder.load_string(the_kv_file)
          self.dialog = MDDialog(title=&quot;my example&quot;, type=&quot;custom&quot;, content_cls=ContentOfAppointmentDialog()) # defining the dialog
          self.AccessDialog = ContentOfAppointmentDialog()
  
          return self.main_screen
  
      def OpenDialog(self):   # opens dialog
          self.dialog.open()
  
  
      def CloseDialog(self):  # closes dialog
          self.dialog.dismiss()
  
  # this is the function that is not working as I intended it to    
      def ChangingLabel(self):    # function that is supposed to change the label to what users input is
          self.main_screen.ids.label_to_change = self.AccessDialog.ids.the_textfield.text
          self.dialog.dismiss()
  
  
  MainApp().run()
  </code></pre>