It’s running! Yeah!

main.py

@@ -0,0 +1,24 @@
+from random import randint
+
+from kivy.app import App
+from kivy.uix.boxlayout import BoxLayout
+
+
+class RanNum(BoxLayout):
+    pass
+
+
+class RanKivApp(App):
+    def build(self):
+        return RanNum()
+
+    def generate_random_number(self):
+        try:
+            upper_boundary = int(self.root.ids.upper_boundary_input.text)
+            self.root.ids.output.text = str(randint(1, upper_boundary))
+        except ValueError:
+            self.root.ids.output.text = 'Bitte nur positive,\nganze Zahlen eingeben!'
+
+
+if __name__ == '__main__':
+    RanKivApp().run()