title: Geeting error in reading a file and pronting it as Label in kivy
body: <p>I am trying to read text from a file and show it as Label in another screen but i am getting error that text file's content in not str even after using str() function.
  Error:
  ValueError: Screen1.usename accept only str</p>
  <pre><code>from kivy.app import App
  from kivy.uix.screenmanager import Screen
  from kivy.lang import Builder
  from kivy.properties import StringProperty
  
  class Screen1(Screen):
      def gb(self):
          f=open('test.txt','r')
          b=f.read()
          t=str(b)
          return t
      usename = StringProperty(&quot;&quot;)
  
  class Screen2(Screen):
      username = StringProperty(&quot;&quot;)
  
  
  root = Builder.load_string('''
  
  &lt;Screen1&gt;:
      BoxLayout:
          orientation: &quot;vertical&quot;
          Button:
              text:'ue'
              on_release: root.usename = root.gb; root.manager.current = &quot;screen2&quot;
  
  
  &lt;Screen2&gt;:
      name: &quot;screen2&quot;
      Label:
          text: root.username
  
  
  ScreenManager:
      Screen1:
          id: loginscreen
      Screen2:
          username: loginscreen.usename
  
  ''')
  
  
  
  class MyApp(App):
      def build(self):
          return root
  r=MyApp()
  r.run()
  </code></pre>