Python | FloatLayout in Kivy using .kv file

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.

👉🏽 Kivy Tutorial – Learn Kivy with Examples.

FloatLayout:

Floatlayout provides us the flexibility to arrange the elements like button relatively i.e it allows us to place the elements using something called relative position. This means rather than defining the specific position or the coordinates we will place everything using the percentage w.r.t the size of window i.e we can dynamically arrange the position of the elements.

The first thing we need to do import FloatLayout –

from kivy.uix.floatlayout import FloatLayout

We have 2 properties to create the dynamic placement –

1) pos_hint: provide hint of position
We can define upto 6 keys i.e. it takes arguments in form of dictionary.
pos_hint = {“x”:1, “y”:1, “left”:1, “right”:1, “top”:1, “bottom”:1}

2) size_hint: provide hint of size
Contains two arguments i.e. width and height

Note:

• You can only use values between 0-1 for both size_hint and pos_hint. Where 0 = 0% and 1 = 100%.
• The coordinate system in kivy works from the bottom left! This will be important when placing our objects. (i.e (0, 0) is the bottom left).

Basic Approach:

1) import kivy
2) import kivyApp
3) import Floatlayout
4) Set minimum version(optional)
5) create Layout class
6) create App class
7) Set up .kv file
8) return Layout/widget/Class(according to requirement)
9) Run an instance of the class

Implementation of the approach –

main.py file

## Sample Python application demonstrating the
## working of FloatLayout in Kivy using .kv file

###################################################
# import modules

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

# module consist the floatlayout
# to work with FloatLayout first
# you have to import it
from kivy.uix.floatlayout import FloatLayout

# To change the kivy default settings
# we use this module config
from kivy.config import Config

# 0 being off 1 being on as in true / false
# you can use 0 or 1 && True or False
Config.set('graphics', 'resizable', True)


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

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

# run the app
if __name__ == "__main__":
    Float_LayoutApp().run()

This file includes the dynamic placements of button i.e as the screen size changes the button adjust themselves relatively this is the benefit of the FloatLayout.

.kv file implementation of approach –

#.kv file implementation of FloatLayout

# creating button feature
<Button>:
    font_size: 40

    # creating button
    # a button 30 % of the width and 50 %
    # of the height of the layout
    size_hint: 0.3, 0.3

<FloatLayout>:

    Button:
        text: "Helooo !!!!! "
        background_color: 0.1, 0.5, 0.6, 1

        # positioned at 0 % right and 100 % up / top
        # from bottom left, i.e x, top = 0, 100 from bottom left:
        pos_hint: {"x":0, "top":1}

    Button:
        text:"Rajnish:)"
        background_color: 1, 0, 0, 1
        pos_hint: {"x":0.35, "y":0.3}


    Button:
        text:"Ravi:)"
        background_color: 0.4, 0.5, 0.6, 1
        pos_hint: {"x":.7, "bottom":0}

    Button:
        text:"Sanjeev:)"
        background_color: 0, 0, 1, 1
        pos_hint: {"x":.7, "top":1}

    Button:
        text:"Suraj:)"
        background_color: 0.8, 0.9, 0.2, 1
        pos_hint: {"x":0, "bottom":1}

Output:

Video Output:

Reference:
https://kivy.org/doc/stable/api-kivy.uix.floatlayout.html
https://techwithtim.net/tutorials/kivy-tutorial/floatlayout/