title: I am getting this error when I am using Screen Manager: kivy.uix.screenmanager.ScreenManagerException: No Screen with name "display"
body: <p>I am making an application using Screen Manager in kivy and I am stuck here. I am new to kivy and python. as far as I know I am doing everything correctly.</p>
  
  <p>error says- </p>
  
  <blockquote>
    <p>kivy.uix.screenmanager.ScreenManagerException: No Screen with name
    "display"</p>
  </blockquote>
  
  <p>Note: this is only a part of my code for the sake of simplicity I am only showing the lines where the error is occuring.</p>
  
  <pre><code>    import kivy
      kivy.require('1.10.0')
  
      from kivy.uix.stacklayout import StackLayout
      from kivy.uix.floatlayout import FloatLayout
      from kivy.uix.boxlayout import BoxLayout
      from kivy.uix.label import Label 
      from kivy.app import App
      from kivy.uix.popup import Popup  
      from kivy.uix.screenmanager import ScreenManager, Screen 
      from kivy.lang import Builder 
      from kivy.properties import ObjectProperty
      from kivy.uix.textinput import TextInput
      from kivy.properties import StringProperty
  
  
      import json
  
      Builder.load_file('VocabularyJournal.kv')
  
      class MenuPage(Screen, StackLayout):
          pass
  
      class DisplayPage(Screen, BoxLayout):
  
  
  
          def __init__(self, *args):# the error occured after I wrote these line before that every other screens were working properly.
              BoxLayout.__init__(self,*args)
              with open('vocab_words.json') as rfile:
                  data=json.load(rfile)
  
              #some codes here
  
      class WordInsertPage(Screen,FloatLayout):
          pass
  
  
      class NewWordPage(Screen,StackLayout):
          pass
  
      class FlashCard(Screen):
          pass
  
      class WordGroups(Screen):
          pass
  
      sm=ScreenManager()
      sm.add_widget(MenuPage(name='menu'))
      sm.add_widget(WordInsertPage(name='insertword'))
      sm.add_widget(NewWordPage(name='newword'))
      sm.add_widget(FlashCard(name='flashcard'))
      sm.add_widget(WordGroups(name='wordgroup'))
      sm.add_widget(DisplayPage(name='display'))
  
      class VocabularyJournalApp(App):
          def build(self):
              return sm
  
      object = VocabularyJournalApp()
      object.run()
  </code></pre>
  
  <p>heres the part of kv file where the error is occuring:</p>
  
  <pre><code>    # the part of the code where the error is occuring
  
      &lt;WordInsertPage&gt;:
  
          FloatLayout:
  
              Button: 
                  text: "New Word"
                  on_press: root.manager.current='newword'# this is working very well
                  font_size: 30
                  color: 0,0,0,1
                  size_hint: .2, .1
                  pos_hint: {"center_x": .5, "center_y": 0.3}
                  background_down: 'darkgrey.png'
              Button:
                  text: "search word"
                  on_press: root.manager.current='display' # here the error says kivy.uix.screenmanager.ScreenManagerException: No Screen with name "display".
  
                  font_size: 30
                  color: 0,0,0,1
                  size_hint: .2, .1
                  pos_hint: {"center_x": .5, "center_y": 0.5}
                  background_down: 'darkgrey.png'
              Button:
                  text: 'Flash Cards'
                  on_press: root.manager.current="flashcard"
                  font_size: 30
                  color: 0,0,0,1
                  size_hint: .2, .1
                  pos_hint: {"center_x": .5, "center_y": 0.7}
                  background_down: 'darkgrey.png'
  </code></pre>
  
  <p>here is the traceback:</p>
  
  <pre><code>    [INFO   ] [Logger      ] Record log in C:\Users\HP\.kivy\logs\kivy_18-03-01_31.txt
      [INFO   ] [Kivy        ] v1.10.0
      [INFO   ] [Python      ] v3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)]
      [INFO   ] [Factory     ] 194 symbols loaded
      [INFO   ] [Image       ] Providers: img_tex, img_dds, img_sdl2, img_gif (img_pil, img_ffpyplayer ignored)
      [INFO   ] [Text        ] Provider: sdl2
      [INFO   ] [OSC         ] using &lt;thread&gt; for socket
      [INFO   ] [Window      ] Provider: sdl2
      [INFO   ] [GL          ] Using the "OpenGL" graphics system
      [INFO   ] [GL          ] GLEW initialization succeeded
      [INFO   ] [GL          ] Backend used &lt;glew&gt;
      [INFO   ] [GL          ] OpenGL version &lt;b'4.4.0 - Build 21.20.16.4627'&gt;
      [INFO   ] [GL          ] OpenGL vendor &lt;b'Intel'&gt;
      [INFO   ] [GL          ] OpenGL renderer &lt;b'Intel(R) HD Graphics 520'&gt;
      [INFO   ] [GL          ] OpenGL parsed version: 4, 4
      [INFO   ] [GL          ] Shading version &lt;b'4.40 - Build 21.20.16.4627'&gt;
      [INFO   ] [GL          ] Texture max size &lt;16384&gt;
      [INFO   ] [GL          ] Texture max units &lt;32&gt;
      [INFO   ] [Shader      ] fragment shader: &lt;b"WARNING: 0:7: '' :  #version directive missing"&gt;
      [INFO   ] [Shader      ] vertex shader: &lt;b"WARNING: 0:7: '' :  #version directive missing"&gt;
      [INFO   ] [Window      ] auto add sdl2 input provider
      [INFO   ] [Window      ] virtual keyboard not allowed, single mode, not docked
      [INFO   ] [GL          ] NPOT texture support is available
      [INFO   ] [Base        ] Start application main loop
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [WARNING] [Accordion   ] not enough space for displaying all children
      [WARNING] [Accordion   ] need 176px, got 100px
      [WARNING] [Accordion   ] layout aborted.
      [INFO   ] [Base        ] Leaving application in progress...
       Traceback (most recent call last):
         File "E:\SharanyaPy\desktop vocabulary journal\vocabJournal.py", line 92, in &lt;module&gt;
           object.run()
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\app.py", line 828, in run
           runTouchApp()
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\base.py", line 504, in runTouchApp
           EventLoop.window.mainloop()
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\core\window\window_sdl2.py", line 663, in mainloop
           self._mainloop()
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\core\window\window_sdl2.py", line 405, in _mainloop
           EventLoop.idle()
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\base.py", line 342, in idle
           self.dispatch_input()
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\base.py", line 327, in dispatch_input
           post_dispatch_input(*pop(0))
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\base.py", line 233, in post_dispatch_input
           listener.dispatch('on_motion', etype, me)
         File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8191)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\core\window\__init__.py", line 1188, in on_motion
           self.dispatch('on_touch_down', me)
         File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8191)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\core\window\__init__.py", line 1204, in on_touch_down
           if w.dispatch('on_touch_down', touch):
         File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8191)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\screenmanager.py", line 1189, in on_touch_down
           return super(ScreenManager, self).on_touch_down(touch)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\widget.py", line 457, in on_touch_down
           if child.dispatch('on_touch_down', touch):
         File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8191)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\relativelayout.py", line 288, in on_touch_down
           ret = super(RelativeLayout, self).on_touch_down(touch)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\widget.py", line 457, in on_touch_down
           if child.dispatch('on_touch_down', touch):
         File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8191)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\widget.py", line 457, in on_touch_down
           if child.dispatch('on_touch_down', touch):
         File "kivy\_event.pyx", line 718, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8191)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\behaviors\button.py", line 151, in on_touch_down
           self.dispatch('on_press')
         File "kivy\_event.pyx", line 714, in kivy._event.EventDispatcher.dispatch (kivy\_event.c:8146)
         File "kivy\_event.pyx", line 1225, in kivy._event.EventObservers.dispatch (kivy\_event.c:14035)
         File "kivy\_event.pyx", line 1109, in kivy._event.EventObservers._dispatch (kivy\_event.c:12816)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\lang\builder.py", line 64, in custom_callback
           exec(__kvlang__.co_value, idmap)
         File "E:\SharanyaPy\desktop vocabulary journal\VocabularyJournal.kv", line 51, in &lt;module&gt;
           on_press: root.manager.current='display'
         File "kivy\properties.pyx", line 478, in kivy.properties.Property.__set__ (kivy\properties.c:5572)
         File "kivy\properties.pyx", line 516, in kivy.properties.Property.set (kivy\properties.c:6405)
         File "kivy\properties.pyx", line 571, in kivy.properties.Property.dispatch (kivy\properties.c:7105)
         File "kivy\_event.pyx", line 1225, in kivy._event.EventObservers.dispatch (kivy\_event.c:14035)
         File "kivy\_event.pyx", line 1131, in kivy._event.EventObservers._dispatch (kivy\_event.c:13193)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\screenmanager.py", line 1037, in on_current
           screen = self.get_screen(value)
         File "C:\Users\HP\AppData\Local\Programs\Python\Python36-32\lib\site-packages\kivy\uix\screenmanager.py", line 1063, in get_screen
           raise ScreenManagerException('No Screen with name "%s".' % name)
       kivy.uix.screenmanager.ScreenManagerException: No Screen with name "display".
  </code></pre>