Why KivyMD on_action_button is not working

Question

Can anyone help me.When working with KivyMD in python syntax the on_action_button parameter of MDBottomAppBar(MDTopAppBar()) does not work.Can anyone guide me why does on_action_button: app.presser() is not working in kivymd

from kivymd.app import MDApp
from kivy.lang import Builder

class MyFirst_App(MDApp):

   def build(self):
       self.theme_cls.theme_style = "Dark"

       self.theme_cls.primary_palette = "BlueGray"

       return Builder.load_file("BottomBar.kv")

   def presser(self):

       print("hello")


MyFirst_App().run()

###############################KVFILE##########################################################

MDBoxLayout:
    orientation: "vertical"

    MDTopAppBar:
            title: " Our Top Bar"

            left_action_items: [["menu",lambda x: app.presser()]]

            right_action_items: [["dots-vertical",lambda x: app.presser()]]

    MDLabel:
            id: my_label

            text:"Some Stuff"

            halign:"center"

    MDBottomAppBar:
            MDTopAppBar:
                    icon: "git"

                    #title: "Bottom Bar"

                    mode: "free-end"

                    #mode: "end"

                    #mode: "center"

                    #mode: "free-center"

                    on_action_button: app.presser()

Answer 1

You create the MDBottomAppBar icons the same way as the MDTopAppBar, just inside the MDBottomAppBar.

ie.

    MDBottomAppBar:
        MDTopAppBar:
            left_action_items: [["account-circle",lambda x: app.presser()]]
            right_action_items: [["account-child",lambda x: app.presser()],["account-child",lambda x: app.presser()]]