test.py

#!/usr/bin/env python
from kivy.app import App
from kivy.core.audio import SoundLoader
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.slider import Slider
from functools import partial


def test(sound, *args):
    print args[1]
    sound.volume = args[1]


class MyWidget(FloatLayout):
    def __init__(self):
        super(MyWidget, self).__init__()
        s = SoundLoader.load('/home/gabriel/Musique/coding music/01 - coding in c.mp3')
        slider = Slider(value=s.volume, min=0, max=1)
        s.play()
        slider.bind(value=partial(test, s))
        self.add_widget(slider)


class MyApp(App):
    def build(self):
        return MyWidget()


if __name__ == '__main__':
    MyApp().run()