How to automatically scroll down in a Kivy ScrollView?

Question

I add widgets to a GridLayout in a ScrollView, so its content expands dynamically.
By default, without user scrolling, the view stays at the top, no matter how many more widgets do you add. If the user scrolls, the view attaches to this point, but it seems a little annoying for me to have to scroll down (even a little bit) for the view to always show the latest content. How can I make it show the downmost part by default?

Here is the sample code just in case:

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import Screen
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.uix.scrollview import ScrollView
from kivy.uix.gridlayout import GridLayout

Builder.load_string('''
<MessageView>:
    canvas:
        Color:
            rgba: 1, 1, 1, 1
        Rectangle:
            pos: self.pos
            size: self.size

<Message>:
    canvas:
        Color:
            rgba: 0, 1, 0, 0.3
        Rectangle:
            pos: self.pos
            size: self.size
''')

class Message(Widget):
    pass

class MessageView(ScrollView):
    pass

class TestApp(App):
    def msg_in(self, btn):
        msg = Message()
        msg.size_hint = [None, None]
        self.msg_layout.add_widget(msg)

    def build(self):
        self.scr = Screen()
        self.sv1_main = MessageView(pos_hint={"top": 0.87, "center_x": 0.5},
                                    size_hint=(0.97, 0.65))
        self.msg_layout = GridLayout(cols=1,
                                     size_hint_y=None)
        self.msg_layout.bind(minimum_height=self.msg_layout.setter('height'))
        self.bt1_main = Button(size_hint=(0.1, 0.078),
                               pos_hint={"top": 0.097, "center_x": 0.927},
                               on_press=self.msg_in)
        self.scr.add_widget(self.sv1_main)
        self.sv1_main.add_widget(self.msg_layout)
        self.scr.add_widget(self.bt1_main)
        return self.scr

TestApp().run()

Answer 1

You can use scroll_to method after adding a new content.

class TestApp(App):
    def msg_in(self, btn):
        msg = Message()
        msg.size_hint = [None, None]
        self.msg_layout.add_widget(msg)
        self.sv1_main.scroll_to(msg)
    # ...