KeyboardListener

Examples

Press any keys

import flet as ft


async def main(page: ft.Page):
    pressed_keys = set()

    def key_down(e: ft.KeyDownEvent):
        pressed_keys.add(e.key)
        keys.controls = [ft.Text(k, size=20) for k in pressed_keys]

    def key_up(e: ft.KeyUpEvent):
        pressed_keys.remove(e.key)
        keys.controls = [ft.Text(k, size=20) for k in pressed_keys]

    page.add(
        ft.Text("Press any keys..."),
        ft.KeyboardListener(
            content=(keys := ft.Row()),
            autofocus=True,
            on_key_down=key_down,
            on_key_up=key_up,
        ),
    )


ft.run(main)

KeyboardListener

Bases: Control

A control that calls a callback whenever the user presses or releases a key on a keyboard.

autofocus

autofocus: bool = False

True if this control will be selected as the initial focus when no other node in its scope is currently focused.

badge

badge: BadgeValue | None = None

A badge to show on top of this control.

col

col: ResponsiveNumber = 12

If a parent of this control is a ResponsiveRow, this property is used to determine how many virtual columns of a screen this control will span.

Can be a number or a dictionary configured to have a different value for specific breakpoints, for example col={"sm": 6}.

This control spans the 12 virtual columns by default.

Dimensions

Breakpoint	Dimension
xs	<576px
sm	≥576px
md	≥768px
lg	≥992px
xl	≥1200px
xxl	≥1400px

content

content: Control

The content control of the keyboard listener.

data

data: Any = skip_field()

Arbitrary data of any type.

disabled

disabled: bool = False

Every control has disabled property which is False by default - control and all its children are enabled.

Note

The value of this property will be propagated down to all children controls recursively.

Example

For example, if you have a form with multiple entry controls you can disable them all together by disabling container:

ft.Column(
    disabled = True,
    controls=[
        ft.TextField(),
        ft.TextField()
    ]
)

expand

expand: bool | int | None = None

Specifies whether/how this control should expand to fill available space in its parent layout.

More information here.

Note

Has effect only if the direct parent of this control is one of the following controls, or their subclasses: Column, Row, View, Page.

expand_loose

expand_loose: bool = False

Allows the control to expand along the main axis if space is available, but does not require it to fill all available space.

More information here.

Note

If expand_loose is True, it will have effect only if:

• expand is not None and
• the direct parent of this control is one of the following controls, or their subclasses: Column, Row, View, Page.

include_semantics

include_semantics: bool = True

Include semantics information in this control.

key

key: KeyValue | None = None

on_key_down

on_key_down: EventHandler[KeyDownEvent] | None = None

Fires when a keyboard key is pressed.

on_key_repeat

on_key_repeat: EventHandler[KeyRepeatEvent] | None = None

Fires when a keyboard key is being hold, causing repeated events.

on_key_up

on_key_up: EventHandler[KeyUpEvent] | None = None

Fires when a keyboard key is released.

opacity

opacity: Number = 1.0

Defines the transparency of the control.

Value ranges from 0.0 (completely transparent) to 1.0 (completely opaque without any transparency).

page

page: Page | PageView | None

The page (of type Page or PageView) to which this control belongs to.

parent

parent: BaseControl | None

The direct ancestor(parent) of this control.

It defaults to None and will only have a value when this control is mounted (added to the page tree).

The Page control (which is the root of the tree) is an exception - it always has parent=None.

rtl

rtl: bool = False

Whether the text direction of the control should be right-to-left (RTL).

tooltip

tooltip: TooltipValue | None = None

The tooltip ot show when this control is hovered over.

visible

visible: bool = True

Every control has visible property which is True by default - control is rendered on the page. Setting visible to False completely prevents control (and all its children if any) from rendering on a page canvas. Hidden controls cannot be focused or selected with a keyboard or mouse and they do not emit any events.

before_event

before_event(e: ControlEvent)

before_update

before_update()

build

build()

Called once during control initialization to define its child controls. self.page is available in this method.

clean

clean() -> None

did_mount

did_mount()

focus

focus()

focus_async

focus_async()

init

init()

is_isolated

is_isolated()

update

update() -> None

will_unmount

will_unmount()