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Radio

Examples#

Live example

Basic Example#

import flet as ft


def main(page: ft.Page):
    def handle_button_click(e: ft.Event[ft.ElevatedButton]):
        message.value = f"Your favorite color is:  {group.value}"
        page.update()

    page.add(
        ft.Text("Select your favorite color:"),
        group := ft.RadioGroup(
            content=ft.Column(
                controls=[
                    ft.Radio(value="red", label="Red"),
                    ft.Radio(value="green", label="Green"),
                    ft.Radio(value="blue", label="Blue"),
                ]
            )
        ),
        ft.ElevatedButton(content="Submit", on_click=handle_button_click),
        message := ft.Text(),
    )


ft.run(main)

basic

Handling selection changes#

import flet as ft


def main(page: ft.Page):
    def handle_selection_change(e: ft.Event[ft.RadioGroup]):
        message.value = f"Your favorite color is:  {e.control.value}"
        page.update()

    page.add(
        ft.Text("Select your favorite color:"),
        ft.RadioGroup(
            on_change=handle_selection_change,
            content=ft.Column(
                controls=[
                    ft.Radio(value="red", label="Red"),
                    ft.Radio(value="green", label="Green"),
                    ft.Radio(value="blue", label="Blue"),
                ]
            ),
        ),
        message := ft.Text(),
    )


ft.run(main)

handling-selection-changes

Styled radio buttons#

import flet as ft


def main(page: ft.Page):
    page.add(
        ft.RadioGroup(
            ft.Column(
                controls=[
                    ft.Radio(label="Radio with default style", value="1"),
                    ft.Radio(
                        label="Radio with constant fill color",
                        value="2",
                        fill_color=ft.Colors.RED,
                    ),
                    ft.Radio(
                        label="Radio with dynamic fill color",
                        value="3",
                        fill_color={
                            ft.ControlState.HOVERED: ft.Colors.BLUE,
                            ft.ControlState.SELECTED: ft.Colors.GREEN,
                            ft.ControlState.DEFAULT: ft.Colors.RED,
                        },
                    ),
                ]
            )
        )
    )


ft.run(main)

Radio #

Bases: ConstrainedControl, AdaptiveControl

Radio buttons let people select a single option from two or more choices.

active_color #

active_color: ColorValue | None = None

The color used to fill this radio when it is selected.

adaptive #

adaptive: bool | None = None

Enables platform-specific rendering or inheritance of adaptiveness from parent controls.

animate_offset #

animate_offset: AnimationValue | None = None

Enables implicit animation of the offset property.

More information here.

animate_opacity #

animate_opacity: AnimationValue | None = None

Enables implicit animation of the opacity property.

More information here.

animate_position #

animate_position: AnimationValue | None = None

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

More information here.

animate_rotation #

animate_rotation: AnimationValue | None = None

Enables implicit animation of the rotate property.

More information here.

animate_scale #

animate_scale: AnimationValue | None = None

Enables implicit animation of the scale property.

More information here.

animate_size #

animate_size: AnimationValue | None = None

TBD

aspect_ratio #

aspect_ratio: Number | None = None

TBD

autofocus #

autofocus: bool = False

True if the control 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 control, Page.overlay list.

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

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.

fill_color #

fill_color: ControlStateValue[ColorValue] | None = None

The color that fills the radio, in all or specific ControlState states.

focus_color #

focus_color: ColorValue | None = None

The color of this radio when it has the input focus.

height #

height: Number | None = None

Imposed Control height in virtual pixels.

hover_color #

hover_color: ColorValue | None = None

The color of this radio when it is hovered.

key #

key: (
    str | int | float | bool | ValueKey | ScrollKey | None
) = None

label #

label: str = ''

The clickable label to display on the right of a Radio.

label_position #

label_position: LabelPosition = RIGHT

Defaults to LabelPosition.RIGHT.

label_style #

label_style: TextStyle | None = None

The label's style.

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 control, Page.overlay list.

mouse_cursor #

mouse_cursor: MouseCursor | None = None

The cursor for a mouse pointer entering or 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[ConstrainedControl] | 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[Radio] | None = None

Called when the control has lost focus.

on_focus #

on_focus: ControlEventHandler[Radio] | 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 overlay color of this radio in all or specific ControlState states.

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.

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 control, Page.overlay 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 splash radius of the circular Material ink response.

toggleable #

toggleable: bool = False

Set to True if this radio button is allowed to be returned to an indeterminate state by selecting it again when selected.

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 control, Page.overlay list.

value #

value: str | None = None

The value to set to containing RadioGroup when the radio is selected.

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.

visual_density #

visual_density: VisualDensity | None = None

Defines how compact the radio's layout will be.

width #

width: Number | None = None

Imposed Control width in virtual pixels.

before_event #

before_event(e: ControlEvent)

before_update #

before_update()

clean #

clean() -> None

did_mount #

did_mount()

init #

init()

is_isolated #

is_isolated()

update #

update() -> None

will_unmount #

will_unmount()