How to make widgets appear from the bottom in scrollview in Python Kivy?

Question

how cen I make these dynamically added widgets appear from the bottom of the scrollview instead of the top. Kind of like WhatssApp or Telegram or Messenger. I am a bit stuck on this one. I tried with PushMatrix and PopMatrix, but then the text appeared upside down.

py file:

from kivy.app import App
from kivy.uix.label import Label
from kivy.uix.widget import Widget
from kivy.lang import Builder
from kivy.core.window import Window


Builder.load_file('scrollview_modification.kv')

class MyLayout(Widget):

    def add_widgets(self):
        settings_label = SettingsLabel(text="Widget added")
        self.ids.widgets.add_widget(settings_label)

class SettingsLabel(Label):
    pass

class AwesomeApp(App):
    def build(self):
        Window.clearcolor = (0,1,1,1)
        return MyLayout()

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

kv file:

<MyLayout>
BoxLayout:
    orientation:'vertical'
    size: root.width, root.height
    size_hint: 1, 0.6
    Button:
        text: "add_widgets"
        on_press: root.add_widgets()
        size_hint: 1, 0.25
    ScrollView:
        do_scroll_x: False
        do_scroll_y: True
        BoxLayout:
            size_hint_y: None
            height: self.minimum_height
            orientation: 'vertical'
            id: widgets
            spacing: 3
            padding: 3

<SettingsLabel>
    markup: True
    bold: True
    size_hint: 1, None
    height: 50
    font_size: 16
    col: (179/255, 89/255, 0 , 1)
    canvas.before:
        Color:
            rgba: self.col
        RoundedRectangle:
            size: self.size
            pos: self.pos
            radius: [10]

Answer 1

To make the dynamically added widgets appear from the bottom of the ScrollView, you can set the height of the widgets BoxLayout to be the sum of the heights of all the widgets it contains. This way, when a new widget is added, it will be placed at the bottom of the ScrollView.

You can modify your kv file like this:

<MyLayout>
BoxLayout:
    orientation:'vertical'
    size: root.width, root.height
    size_hint: 1, 0.6
    Button:
        text: "add_widgets"
        on_press: root.add_widgets()
        size_hint: 1, 0.25
    ScrollView:
        do_scroll_x: False
        do_scroll_y: True
        BoxLayout:
            size_hint_y: None
            height: self.minimum_height
            orientation: 'vertical'
            id: widgets
            spacing: 3
            padding: 3

and the python script as

class MyLayout(Widget):

def add_widgets(self):
    settings_label = SettingsLabel(text="Widget added")
    self.ids.widgets.add_widget(settings_label)
    self.ids.scroll_to(settings_label)
    self.ids.widgets.height = sum(child.height for child in self.ids.widgets.children)

This will make the new widget appear at the bottom of the ScrollView. Note that if the ScrollView is not full, the new widget may appear near the top, but as more widgets are added, they will appear at the bottom.