popup - Why are parentheses needed in Kivy but not in Python? -

popup - Why are parentheses needed in Kivy but not in Python? -

if want add together on_press event popup in program, can straight in python or using kv language.

if utilize python, example

from kivy.app import app kivy.uix.popup import popup kivy.uix.button import button class somepopup(popup): pass class somebox(box): popup = somepopup() popup.title = 'anything' popup.content = button(text='anytext', on_press=popup.dismiss)

and in kv language, supposing create same popup, be.

<somepopup> title: 'anything' content: popupcontent button: id: popupcontent text: 'anytext' on_press: root.dismiss()

so, in python, have utilize on_press=popup.dismiss , in kv language on_press: root_dismiss()

i don't understand why in kivy language should utilize parentheses , not in python. help me please?

although both accomplish same things, kv , python them in different ways.

in python, when button(text='anytext', on_press=popup.dismiss), you're telling kivy: when press occurs, phone call popup.dismiss method. is, you're passing object (a class method in case) kivy phone call @ right time.

in kv, when on_press: root.dismiss(), when press event occurs, kivy execute whatever text after colon (root.dismiss() in case). need phone call root.dismiss() in text.

python popup kivy