Introduction

What is Flet?

Flet is a framework that allows building web, desktop and mobile applications in Python without prior experience in frontend development.

You can build a UI for your program with Flet controls which are based on Flutter by Google. Flet goes beyond merely wrapping Flutter widgets. It adds its own touch by combining smaller widgets, simplifying complexities, implementing UI best practices, and applying sensible defaults. This ensures that your applications look stylish and polished without requiring additional design efforts on your part.

Flet app example

Create a sample "Counter" app:

counter.py
import flet as ft

def main(page: ft.Page):
    page.title = "Flet counter example"
    page.vertical_alignment = ft.MainAxisAlignment.CENTER

    txt_number = ft.TextField(value="0", text_align=ft.TextAlign.RIGHT, width=100)

    def minus_click(e):
        txt_number.value = str(int(txt_number.value) - 1)
        page.update()

    def plus_click(e):
        txt_number.value = str(int(txt_number.value) + 1)
        page.update()

    page.add(
        ft.Row(
            [
                ft.IconButton(ft.icons.REMOVE, on_click=minus_click),
                txt_number,
                ft.IconButton(ft.icons.ADD, on_click=plus_click),
            ],
            alignment=ft.MainAxisAlignment.CENTER,
        )
    )

ft.app(main)