title: Get textinput value in Kivy app
body: <p>New to Python/Kivy trying to build a test app with an input box, an ok button and a label that should change text when the ok button is clicked. But instead I get 'NameError: global name 'txt1' is not defined'. What am I doing wrong?</p>
  
  <pre><code># import Kivy
  import kivy
  import random
  
  from kivy.app import App
  from kivy.uix.button import Button
  from kivy.uix.boxlayout import BoxLayout
  from kivy.uix.label import Label
  from kivy.uix.textinput import TextInput
  
  # my app
  class MyApp(App):
  # layout
      def build(self):
          layout = BoxLayout(padding=10, orientation='vertical')
          btn1 = Button(text="OK")
          btn1.bind(on_press=self.buttonClicked)
          layout.add_widget(btn1)
          lbl1 = Label(text="test")
          layout.add_widget(lbl1)
          txt1 = TextInput(text='', multiline=False)
          layout.add_widget(txt1)
          return layout
  
  # button click function
      def buttonClicked(self,btn):
          lbl1.text = "You wrote " + txt1.text
  
  # run app
  if __name__ == "__main__":
      MyApp().run()
  </code></pre>