example.py

from kivy.metrics import dp

from kivymd.app import MDApp
from kivymd.uix.datatables import MDDataTable
from kivymd.uix.boxlayout import MDBoxLayout
from kivymd.uix.floatlayout import MDFloatLayout
from kivymd.uix.button import MDRaisedButton


class Example(MDApp):
    data_tables = None

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

        layout = MDFloatLayout()  # root layout
        # Creating control buttons.
        button_box = MDBoxLayout(
            pos_hint={"center_x": 0.5},
            adaptive_size=True,
            padding="24dp",
            spacing="24dp",
        )

        for button_text in ["Add row", "Remove row"]:
            button_box.add_widget(
                MDRaisedButton(
                    text=button_text, on_release=self.on_button_press
                )
            )

        # Create a table.
        self.data_tables = MDDataTable(
            pos_hint={"center_y": 0.5, "center_x": 0.5},
            size_hint=(0.9, 0.6),
            use_pagination=False,
            column_data=[
                ("No.", dp(30)),
                ("Column 1", dp(40)),
                ("Column 2", dp(40)),
                ("Column 3", dp(40)),
            ],
            row_data=[("1", "1", "2", "3")],
        )
        # Adding a table and buttons to the toot layout.
        layout.add_widget(self.data_tables)
        layout.add_widget(button_box)

        return layout

    def on_button_press(self, instance_button: MDRaisedButton) -> None:
        '''Called when a control button is clicked.'''

        try:
            {
                "Add row": self.add_row,
                "Remove row": self.remove_row,
            }[instance_button.text]()
        except KeyError:
            pass

    def add_row(self) -> None:
        last_num_row = int(self.data_tables.row_data[-1][0])
        self.data_tables.add_row((str(last_num_row + 1), "1", "2", "3"))

    def remove_row(self) -> None:
        if len(self.data_tables.row_data) > 1:
            self.data_tables.remove_row(self.data_tables.row_data[-1])


Example().run()