Switch

Examples

Live example

Basic Example

import flet as ft


def main(page: ft.Page):
    def handle_button_click(e: ft.Event[ft.Button]):
        message.value = (
            f"Switch values are:  {c1.value}, {c2.value}, {c3.value}, {c4.value}."
        )
        page.update()

    page.add(
        c1 := ft.Switch(label="Unchecked switch", value=False),
        c2 := ft.Switch(label="Checked switch", value=True),
        c3 := ft.Switch(label="Disabled switch", disabled=True),
        c4 := ft.Switch(
            label="Switch with rendered label_position='left'",
            label_position=ft.LabelPosition.LEFT,
        ),
        ft.Button(content="Submit", on_click=handle_button_click),
        message := ft.Text(),
    )


ft.run(main)

Handling change events

import flet as ft


def main(page: ft.Page):
    def handle_switch_change(e: ft.Event[ft.Switch]):
        page.theme_mode = (
            ft.ThemeMode.DARK
            if page.theme_mode == ft.ThemeMode.LIGHT
            else ft.ThemeMode.LIGHT
        )
        e.control.label = (
            "Light ThemeMode"
            if page.theme_mode == ft.ThemeMode.LIGHT
            else "Dark ThemeMode"
        )
        page.update()

    page.theme_mode = ft.ThemeMode.LIGHT
    page.add(ft.Switch(label="Light ThemeMode", on_change=handle_switch_change))


ft.run(main)

Switch

Bases: LayoutControl, AdaptiveControl

A toggle represents a physical switch that allows someone to choose between two mutually exclusive options.

For example, "On/Off", "Show/Hide".

RAISES	DESCRIPTION
AssertionError	If splash_radius is negative.

active_color

active_color: ColorValue | None = None

The color to use when this switch is on.

active_track_color

active_track_color: ColorValue | None = None

The color to use on the track when this switch is on.

If track_color returns a non-none color in the ControlState.SELECTED state, it will be used instead of this color.

adaptive

adaptive: bool | None = None

Whether an adaptive Switch should be created based on the target platform.

On iOS and macOS, a CupertinoSwitch is created, which has matching functionality and presentation as Switch, and the graphics as expected on iOS. On other platforms, a Material Switch is created.

Defaults to False. See the example of usage here.

align

align: Alignment | None = None

Alignment of the control within its parent.

animate_align

animate_align: AnimationValue | None = None

Enables implicit animation of the [align][flet.LayoutControl.] property.

More information here.

animate_margin

animate_margin: AnimationValue | None = None

Enables implicit animation of the [margin][flet.LayoutControl.] property.

More information here.

animate_offset

animate_offset: AnimationValue | None = None

Enables implicit animation of the [offset][flet.LayoutControl.] property.

More information here.

animate_opacity

animate_opacity: AnimationValue | None = None

Enables implicit animation of the [opacity][flet.LayoutControl.] property.

More information here.

animate_position

animate_position: AnimationValue | None = None

Enables implicit animation of the positioning properties ([left][flet.LayoutControl.], [right][flet.LayoutControl.], [top][flet.LayoutControl.] and [bottom][flet.LayoutControl.]).

More information here.

animate_rotation

animate_rotation: AnimationValue | None = None

Enables implicit animation of the [rotate][flet.LayoutControl.] property.

More information here.

animate_scale

animate_scale: AnimationValue | None = None

Enables implicit animation of the [scale][flet.LayoutControl.] property.

More information here.

animate_size

animate_size: AnimationValue | None = None

TBD

aspect_ratio

aspect_ratio: Number | None = None

The aspect ratio of the control. It is defined as the ratio of the width to the height.

autofocus

autofocus: bool = False

Whether this switch will be selected as the initial focus. If there is more than one control on a page with autofocus set, then the first one added to the page will get focus.

badge

badge: BadgeValue | None = None

A badge to show on top of this control.

bottom

bottom: Number | None = None

The distance that the child's bottom edge is inset from the bottom of the stack.

Note

Effective only if this control is a descendant of one of the following: [Stack][flet.] control, [Page.overlay][flet.] list.

col

col: ResponsiveNumber = 12

If a parent of this control is a [ResponsiveRow][flet.], 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

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][flet.], [Row][flet.], [View][flet.], [Page][flet.].

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][flet.], [Row][flet.], [View][flet.], [Page][flet.].

focus_color

focus_color: ColorValue | None = None

The color to use for the focus highlight for keyboard interactions.

height

height: Number | None = None

Imposed Control height in virtual pixels.

hover_color

hover_color: ColorValue | None = None

The color to be used when it is being hovered over by the mouse pointer.

inactive_thumb_color

inactive_thumb_color: ColorValue | None = None

The color to use on the thumb when this switch is off.

Defaults to colors defined in the material design specification.

If thumb_color returns a non-none color in the ControlState.DEFAULT state, it will be used instead of this color.

inactive_track_color

inactive_track_color: ColorValue | None = None

The color to use on the track when this switch is off.

Defaults to colors defined in the material design specification.

If track_color returns a non-none color in the ControlState.DEFAULT state, it will be used instead of this color.

key

key: KeyValue | None = None

label

label: StrOrControl | None = None

The clickable label to display on the right of this switch.

label_position

label_position: LabelPosition = RIGHT

The position of the label, if provided.

label_text_style

label_text_style: TextStyle | None = None

The label's text style, when it is a string.

left

left: Number | None = None

The distance that the child's left edge is inset from the left of the stack.

Note

Effective only if this control is a descendant of one of the following: [Stack][flet.] control, [Page.overlay][flet.] list.

margin

margin: MarginValue | None = None

Sets the margin of the control.

mouse_cursor

mouse_cursor: MouseCursor | None = None

The cursor to be displayed when a mouse pointer enters or is hovering over this control.

offset

offset: OffsetValue | None = None

Applies a translation transformation before painting the control.

The translation is expressed as an Offset scaled to the control's size. So, Offset(x=0.25, y=0), for example, will result in a horizontal translation of one quarter the width of this control.

Example

The following example displays container at 0, 0 top left corner of a stack as transform applies -1 * 100, -1 * 100 (offset * control's size) horizontal and vertical translations to the control:

import flet as ft

def main(page: ft.Page):
    page.add(
        ft.Stack(
            width=1000,
            height=1000,
            controls=[
                ft.Container(
                    bgcolor="red",
                    width=100,
                    height=100,
                    left=100,
                    top=100,
                    offset=ft.Offset(-1, -1),
                )
            ],
        )
    )

ft.run(main)

on_animation_end

on_animation_end: (
    ControlEventHandler[LayoutControl] | None
) = None

Called when animation completes.

Can be used to chain multiple animations.

The data property of the event handler argument contains the name of the animation.

More information here.

on_blur

on_blur: ControlEventHandler[Switch] | None = None

Called when the control has lost focus.

on_change

on_change: ControlEventHandler[Switch] | None = None

Called when the state of the Switch is changed.

on_focus

on_focus: ControlEventHandler[Switch] | None = None

Called when the control has received focus.

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).

overlay_color

overlay_color: ControlStateValue[ColorValue] | None = None

The color for the switch's Material in various ControlState states.

The following states are supported: ControlState.PRESSED, ControlState.SELECTED, ControlState.HOVERED, ControlState.FOCUSED and ControlState.DEFAULT.

padding

padding: PaddingValue | None = None

The amount of space to surround the child inside the bounds of the Switch.

Defaults to horizontal padding of 4 pixels. If Theme.use_material3 is false, then there is no padding by default.

page

page: Page | BasePage | None

The page 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.

right

right: Number | None = None

The distance that the child's right edge is inset from the right of the stack.

Note

Effective only if this control is a descendant of one of the following: [Stack][flet.] control, [Page.overlay][flet.] list.

rotate

rotate: RotateValue | None = None

Transforms this control using a rotation around its center.

The value of rotate property could be one of the following types:

• number - a rotation in clockwise radians. Full circle 360° is math.pi * 2 radians, 90° is pi / 2, 45° is pi / 4, etc.
• Rotate - allows to specify rotation angle as well as alignment - the location of rotation center.

Example

For example:

ft.Image(
    src="https://picsum.photos/100/100",
    width=100,
    height=100,
    border_radius=5,
    rotate=Rotate(angle=0.25 * pi, alignment=ft.Alignment.CENTER_LEFT)
)

rtl

rtl: bool = False

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

scale

scale: ScaleValue | None = None

Scales this control along the 2D plane. Default scale factor is 1.0, meaning no-scale.

Setting this property to 0.5, for example, makes this control twice smaller, while 2.0 makes it twice larger.

Different scale multipliers can be specified for x and y axis, by setting Control.scale property to an instance of Scale class. Either scale or scale_x and scale_y could be specified, but not all of them.

Example

ft.Image(
    src="https://picsum.photos/100/100",
    width=100,
    height=100,
    border_radius=5,
    scale=ft.Scale(scale_x=2, scale_y=0.5)
)

splash_radius

splash_radius: Number | None = None

The radius of the splash effect when the switch is pressed.

thumb_color

thumb_color: ControlStateValue[ColorValue] | None = None

The color of this switch's thumb in various ControlState states.

The following states are supported: ControlState.SELECTED, ControlState.HOVERED, ControlState.DISABLED, ControlState.FOCUSED and ControlState.DEFAULT (fallback).

thumb_icon

thumb_icon: ControlStateValue[IconData] | None = None

The icon of this Switch's thumb in various ControlState states.

The following states are supported: ControlState.SELECTED, ControlState.HOVERED, ControlState.DISABLED, ControlState.FOCUSED and ControlState.DEFAULT (fallback).

tooltip

tooltip: TooltipValue | None = None

The tooltip ot show when this control is hovered over.

top

top: Number | None = None

The distance that the child's top edge is inset from the top of the stack.

Note

Effective only if this control is a descendant of one of the following: [Stack][flet.] control, [Page.overlay][flet.] list.

track_color

track_color: ControlStateValue[ColorValue] | None = None

The color of this switch's track in various ControlState states.

The following states are supported: ControlState.SELECTED, ControlState.HOVERED, ControlState.DISABLED, ControlState.FOCUSED and ControlState.DEFAULT (fallback).

track_outline_color

track_outline_color: (
    ControlStateValue[ColorValue] | None
) = None

The outline color of this switch's track in various ControlState states.

The following states are supported: ControlState.SELECTED, ControlState.HOVERED, ControlState.DISABLED, ControlState.FOCUSED and ControlState.DEFAULT (fallback).

track_outline_width

track_outline_width: (
    ControlStateValue[Number | None] | None
) = None

The outline width of this switch's track in all or specific ControlState states.

The following states are supported: ControlState.SELECTED, ControlState.HOVERED, ControlState.DISABLED, ControlState.FOCUSED and ControlState.DEFAULT (fallback).

value

value: bool = False

Current value of this switch.

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.

width

width: Number | None = None

Imposed Control width in virtual pixels.

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()

init

init()

is_isolated

is_isolated()

update

update() -> None

will_unmount

will_unmount()