Python | Layouts in layouts (Multiple Layouts) in Kivy

Kivy is a platform independent GUI tool in Python. As it can be run on Android, IOS, linux and Windows etc. It is basically used to develop the Android application, but it does not mean that it can not be used on Desktops applications.
In this article, we are going to discuss how we can use layouts in layouts basically multiple Layouts the most basic example of it. 
Most of the time we are able to use one layout but having difficulty to use multiple layouts.

Kivy Tutorial – Learn Kivy with Examples.

In kivy there are many Types of Layouts:  

1. AnchorLayout: Widgets can be anchored to the ‘top’, ‘bottom’, ‘left’, ‘right’ or ‘center’.
2. BoxLayout: Widgets are arranged sequentially, in either a ‘vertical’ or a ‘horizontal’ orientation.
3. FloatLayout: Widgets are essentially unrestricted.
4. RelativeLayout: Child widgets are positioned relative to the layout.
5. GridLayout: Widgets are arranged in a grid defined by the rows and cols properties.
6. PageLayout: Used to create simple multi-page layouts, in a way that allows easy flipping from one page to another using borders.
7. ScatterLayout: Widgets are positioned similarly to a RelativeLayout, but they can be translated, rotate and scaled.
8. StackLayout: Widgets are stacked in a lr-tb (left to right then top to bottom) or tb-lr order.

Note:You can use as many as you can in a single file.

Basic Approach to create multiple layouts in one file:  

1) import kivy
2) import kivyApp
3) import BoxLayout
4) import 
4) set minimum version(optional)
5) Extend the container class
6) set up .kv file :
7) create App class
8) return container class or layout
9) Run an instance of the class

Implementation of the Approach –
main.py file

Note:
If you were using .kv file to make multiple layouts There is no need to import Gridlayout, Boxlayout, AnchorLayout, FloatLayout, StackLayout, PageLayout, Button, etc. As .kv file supports all this as It has all this imported already. But if doing this without .kv file you must have to import these. 

Python3

## Sample Python application demonstrating the
## Program of How to use Multiple Layouts in Single file

########################################################################

# import kivy module
import kivy

# base Class of your App inherits from the App class.
# app:always refers to the instance of your application
from kivy.app import App

# this restrict the kivy version i.e
# below this kivy version you cannot
# use the app or software
kivy.require('1.9.0')

# creates the button in kivy
# if not imported shows the error
from kivy.uix.button import Button

# BoxLayout arranges children in a vertical or horizontal box.
# or help to put the childrens at the desired location.
from kivy.uix.boxlayout import BoxLayout

# The GridLayout arranges children in a matrix.
# It takes the available space and
# divides it into columns and rows,
# then adds widgets to the resulting “cells”.
from kivy.uix.gridlayout import GridLayout

# The PageLayout class is used to create
# a simple multi-page layout,
# in a way that allows easy flipping from
# one page to another using borders.
from kivy.uix.pagelayout import PageLayout


########################################################################

# creating the root widget used in .kv file
class MultipleLayout(PageLayout):
    pass

########################################################################

# creating the App class in which name
#.kv file is to be named PageLayout.kv
class Multiple_LayoutApp(App):
    # defining build()
    def build(self):
        # returning the instance of root class
        return MultipleLayout()

########################################################################

# creating object of Multiple_LayoutApp() class
MlApp = Multiple_LayoutApp()

# run the class
MlApp.run()

In this file we are creating/using all the layout as it is Simpler to built/ use all these in .kv file 
.kv file of the code

Python3

# Program of How to use Multiple Layouts in Single .kv file

########################################################################

# creating page Layout
<PageLayout>:

#########################################################################

    # Creating Page 1

    # Using BoxLayout inside PageLayout
    BoxLayout:

        # creating Canvas
        canvas:
            Color:
                rgba: 216 / 255., 195 / 255., 88 / 255., 1
            Rectangle:
                pos: self.pos
                size: self.size

        # Providing orientation to the BoxLayout
        orientation: 'vertical'

        # Adding Label to Page 1
        Label:
            size_hint_y: None
            height: 1.5 * self.texture_size[1]
            text: 'page 1'

        # Creating Button
        Button:
            text: 'GFG :)'

            # Adding On_press function
            # i.e binding function to press / touch
            on_press: print("This Is The First Page")

#########################################################################

    # Creating Page 2

    BoxLayout:
        orientation: 'vertical'
        canvas:
            Color:
                rgba: 109 / 255., 8 / 255., 57 / 255., 1
            Rectangle:
                pos: self.pos
                size: self.size
        Label:
            text: 'page 2'

        # This Image is directly from the websource
        # By using AsyncImage you can use that
        AsyncImage:
            source: 'http://kivy.org / logos / kivy-logo-black-64.png'

##########################################################################

    # Creating Page 3

    # Using The Second Layout
    # Creating GridLayout
    GridLayout:


        canvas:
            Color:
                rgba: 37 / 255., 39 / 255., 30 / 255., 1
            Rectangle:
                pos: self.pos
                size: self.size


        # Adding grids to Page 3
        # It may be row or column
        cols: 2


        # In first Grid
        # Adding Label + Image
        Label:
            text: 'page 3'

        AsyncImage:
            source: 'http://kivy.org/slides/kivyandroid-thumb.jpg'


        # In Second Grid
        # Adding Button + Image
        Button:
            text: 'Its User:):)'
            on_press: print("Heloo User This is the Last Page")

        AsyncImage:
            source: 'http://kivy.org/slides/kivypictures-thumb.jpg'


        # In third grid
        # Adding Widget + Image

        Widget

        AsyncImage:
            source: 'http://kivy.org/slides/particlepanda-thumb.jpg'

Output:
Image 1:

Image 2:

Image 3:

Video Output:

Reference: https://kivy.org/doc/stable/gettingstarted/layouts.html