ScrollableControl

ScrollableControl

Bases: Control

auto_scroll

auto_scroll: bool = False

True if scrollbar should automatically move its position to the end when children updated. Must be False for scroll_to() method to work.

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][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.].

key

key: KeyValue | None = None

on_scroll

on_scroll: EventHandler[OnScrollEvent] | None = None

Called when scroll position is changed by a user. class.

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 | 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.

rtl

rtl: bool = False

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

scroll

scroll: ScrollMode | None = None

Enables a vertical scrolling for the Column to prevent its content overflow.

Defaults to ScrollMode.None.

scroll_interval

scroll_interval: Number = 10

Throttling in milliseconds for on_scroll event.

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()

init

init()

is_isolated

is_isolated()

scroll_to

scroll_to(
    offset: float | None = None,
    delta: float | None = None,
    scroll_key: str
    | int
    | float
    | bool
    | ScrollKey
    | None = None,
    duration: DurationValue | None = None,
    curve: AnimationCurve | None = None,
)

Moves scroll position to either absolute offset, relative delta or jump to the control with specified key.

offset is an absolute value between minimum and maximum extents of a scrollable control, for example:

await products.scroll_to(offset=100, duration=1000)

offset could be a negative to scroll from the end of a scrollable. For example, to scroll to the very end:

await products.scroll_to(offset=-1, duration=1000)

delta allows moving scroll relatively to the current position. Use positive delta to scroll forward and negative delta to scroll backward. For example, to move scroll on 50 pixels forward:

await products.scroll_to(delta=50)

key allows moving scroll position to a control with specified key. Most of Flet controls have key property which is translated to Flutter as "global key". key must be unique for the entire page/view. For example:

import flet as ft


def main(page: ft.Page):
    cl = ft.Column(
        spacing=10,
        height=200,
        width=200,
        scroll=ft.ScrollMode.ALWAYS,
    )
    for i in range(0, 50):
        cl.controls.append(ft.Text(f"Text line {i}", key=str(i)))

    async def scroll_to_key(e):
        await cl.scroll_to(scroll_key="20", duration=1000)

    page.add(
        ft.Container(cl, border=ft.border.all(1)),
        ft.Button("Scroll to key '20'", on_click=scroll_to_key),
    )


ft.run(main)

Note

scroll_to() method won't work with ListView and GridView controls building their items dynamically.

duration is scrolling animation duration in milliseconds. Defaults to 0 - no animation.

curve configures animation curve. Property value is [AnimationCurve][flet.] enum.

Defaults to AnimationCurve.EASE.

update

update() -> None

will_unmount

will_unmount()