Python - Kivy - example

# --- main.py ---

from kivy.app import App
from kivy.uix.boxlayout import BoxLayout

class ChoseFile(BoxLayout):

    def select(self, *args):
        try:
            self.ids.label.text = args[1][0]
        except Exception as ex:
            print(ex)
        else:
            print(self.ids.label.text)


class ChoseFileApp(App):

    def build(self):
        return ChoseFile()


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


# --- chosefile.kv ---

<ChoseFile>:
    FileChooserListView:
        canvas.before:
            Color:
                rgb: .4,.5,.5
            Rectangle:
                pos: self.pos
                size: self.size
        on_selection: root.select(*args)
    FileChooserIconView:
        canvas.before:
            Color:
                rgb: .5,.4,.5
            Rectangle:
                pos: self.pos
                size: self.size
        on_selection: root.select(*args)
    Label:
        id: label
        size_hint_y: .1
        canvas.before:
            Color:
                rgb: .5,.5,.4
            Rectangle:
                pos: self.pos
                size: self.size