kv 24 popup

#popup.py

from kivy.app import App

from kivy.uix.floatlayout import FloatLayout

from kivy.uix.popup import Popup

from kivy.uix.widget import Widget

class P(FloatLayout):

    pass

class Popup1(Widget):

    def btn(self):

        popupWindow = Popup(title="Popup Window", content=P(),

                            size_hint=(None, None), size=(400, 400))

        popupWindow.open()

class PopupApp(App):

    def build(self):

        return Popup1()

PopupApp().run()

-------------------------------

#popup.kv

<Popup1>:

    Button:

        text: "Open popup"

        size: root.width, 0.2*root.height

        on_release: root.btn()

<p>:

    Label:

        text: "Popup button pressed"

        size_hint: 0.6, 0.2

        pos_hint: {"x":0.2, "top":1}

    Button:

        text: "click outside to close popup"

        size_hint: 0.8, 0.2

        pos_hint: {"x": 0.1, "y":0.1}

reference:

https://www.youtube.com/watch?v=PpLuyOzCKTQ