title: Kivy - how to change size of elements inside grid layout?
body: <p>I'm new to the kivy framework and am trying to use a GridLayout to create three columns. Inside the 3rd column, I want to change the width of the element to be smaller and aligned to the right (I do not want to change the entire column width), however my attempts are not working.    </p>
  
  <p>main.py</p>
  
  <pre><code>from kivy.app import App
  from kivy.uix.widget import Widget
  
  class AppCore(Widget):
      pass
  
  class TestApp(App):
      def build(self):
          return AppCore()
  
  def run_app():
      TestApp().run()
  
  if __name__ == '__main__':
      run_app()
  </code></pre>
  
  <p>test.kv</p>
  
  <pre><code>&lt;AppCore&gt;
      GridLayout:
          cols: 3
          size: root.width * 0.8, root.height * 0.8
  
          row_default_height: 30
          row_force_default: True
          center: root.width / 2, root.height / 2
  
          Label:
              text: 'hello world'
  
          TextInput:
              id: text_field
              multiline: False
  
          Button:
              id: f_but
              padding_right: 0
              width: 10
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/KEJKJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KEJKJ.png" alt="enter image description here"></a></p>