title: kivy NumericProperty to StringProperty
body: <p>I tried to make my own Coockie Clicker in kivy, but with cristmas coockies.
  I created an Image of an Coockie, you can click on and an Label that shows you how many times you have clicked.
  The Label required an String, so I tried to convert the numeric property into an string, but it did not work, because I got the error message: </p>
  
  <pre><code>&lt;kivy.properties.NumericProperty object at 0xa6e32cc&gt;
  </code></pre>
  
  <p>This is the part of the code, where I suspect the error:</p>
  
  <pre><code>class Kecks(Widget):
  
      count = NumericProperty(0)
      amount = NumericProperty(1)
      txt = StringProperty(str(count))
  </code></pre>
  
  <p>Here is the rest of the code:</p>
  
  <pre><code>from kivy.app import App
  from kivy.lang import Builder
  
  from kivy.uix.widget import Widget
  from kivy.uix.label import Label
  from kivy.core.window import Window
  
  from kivy.clock import Clock
  from kivy.animation import Animation
  from  kivy.core.text.markup import *
  
  from kivy.uix.floatlayout import FloatLayout
  from kivy.properties import NumericProperty
  from kivy.properties import StringProperty
  
  Builder.load_string('''
  &lt;Root&gt;:
  
      Kecks:
          pos: 300, 300
  &lt;Kecks&gt;:
      Image:
          pos: root.pos
          id: my_image
          source: 'piernik.png'
  
      Label:
          id: my_Label
          font_size: 50
          text: root.txt
          center_x: root.width / 4
  
  ''')
  
  class Root(FloatLayout):
      pass
  
  class Kecks(Widget):
  
      count = NumericProperty(0)
      amount = NumericProperty(1)
      txt = StringProperty(str(count))
  
      def on_touch_down(self, touch):
          if self.collide_point(*touch.pos):
              self.count += self.amount
              print self.txt
  
  
  class app(App):
      def build(self):
          Window.clearcolor = (10, 0, 0, 1)
          return Root()
  
  if __name__ == "__main__":
      app().run()
  </code></pre>