Introduction

Flet is a framework for building web, desktop, and mobile applications using Python. It requires no prior frontend development experience.

Flet App Example: Counter

This example demonstrates a simple counter application.

Code (counter.py)

import flet as ft
def main(page: ft.Page):
    page.title = "Flet counter example"
    page.vertical_alignment = ft.MainAxisAlignment.CENTER
    input = ft.TextField(value="0", text_align=ft.TextAlign.RIGHT, width=100)
    def minus_click(e):
        input.value = str(int(input.value) - 1)
        page.update() # Added for completeness, though not in original text
    def plus_click(e):
        input.value = str(int(input.value) + 1)
        page.update() # Added for completeness, though not in original text
    page.add(
        ft.Row(
            alignment=ft.MainAxisAlignment.CENTER,
            controls=[
                ft.IconButton(ft.Icons.REMOVE, on_click=minus_click),
                input,
                ft.IconButton(ft.Icons.ADD, on_click=plus_click),
            ],
        )
    )
ft.run(main)

Running the App

1. **Install Flet:**

    pip install 'flet[all]'
    

2. **Launch the app:**

    flet run counter.py
    

This opens the app in a native OS window.

3. **Run as a web app:**

    flet run --web counter.py
    

Related Documentation Sections

[Getting Started](https://docs.flet.dev/getting-started/)

[Installation](https://docs.flet.dev/getting-started/installation/)

[API Reference](https://docs.flet.dev/api-reference/)

[Cookbook](https://docs.flet.dev/cookbook/)

[Publishing Flet app](https://docs.flet.dev/publish/)

[Extending Flet](https://docs.flet.dev/extend/)