BasePage

A visual container representing a top-level view in a Flet application.

BasePage serves as the base class for Page and MultiView, and provides a unified surface for rendering application content, app bars, navigation elements, dialogs, overlays, and more. It manages one or more View instances and exposes high-level layout, scrolling, and theming properties.

Unlike lower-level layout controls (e.g., Column, Container), BasePage represents an entire logical view or screen of the app. It provides direct access to view-level controls such as AppBar, NavigationBar, FloatingActionButton, and supports system-level events like window resizing and media changes.

This class is not intended to be used directly in most apps; instead, use Page or MultiView, which extend this base functionality.

Inherits: AdaptiveControl

Properties

• appbar - Gets or sets the top application bar (AppBar or CupertinoAppBar) for the view.
• auto_scroll - Whether root view should auto-scroll to the end on content changes.
• bgcolor - Background color of the root view.
• bottom_appbar - Bottom app bar displayed in the root view.
• controls - Root view content controls displayed by this page.
• dark_theme - Customizes the theme of the application when in dark theme mode.
• decoration - Background decoration of the root view container.
• drawer - Navigation drawer opened from the leading edge.
• enable_screenshots - Enable taking screenshots of the entire page with take_screenshot method.
• end_drawer - Navigation drawer opened from the trailing edge.
• floating_action_button - Floating action button shown for the root view.
• floating_action_button_location - Placement of the floating action button in the root view.
• foreground_decoration - Foreground decoration painted above root view content.
• height - Page height in logical pixels.
• horizontal_alignment - Horizontal alignment of root view child controls.
• locale_configuration - Configures supported locales and the current locale.
• media - The current environmental metrics of the page or window.
• navigation_bar - Bottom navigation bar for the root view.
• overlay - The list of overlay controls rendered above page content.
• padding - Inner padding for the root view content.
• scroll - Scroll behavior mode for root view content.
• services - Service instances attached to the root view lifecycle.
• show_semantics_debugger - Whether to turn on an overlay that shows the accessibility information reported by the framework.
• spacing - Default spacing between root view child controls.
• theme - Customizes the theme of the application when in light theme mode.
• theme_animation_style - Overrides the default animation style used when the application's theme is changed (for example, when theme_mode switches between light and dark).
• theme_mode - The page's theme mode.
• title - Page or window title.
• vertical_alignment - Vertical alignment of root view child controls.
• views - A list of views managed by the page.
• width - Page width in logical pixels.

Events

• on_media_change - Called when media has changed.
• on_resize - Called when a user resizes a browser or native OS window containing Flet app

Methods

• add - Adds controls to the page.
• clean - Remove all root view controls and send update to the client.
• close_drawer - Close the drawer.
• close_end_drawer - Close the end drawer.
• insert - Inserts controls at specific index of page.controls list.
• pop_dialog - Closes the most recently opened dialog.
• remove - Removes specific controls from page.controls list.
• remove_at - Remove controls from page.controls list at specific index.
• scroll_to - Moves scroll position to either absolute offset, relative delta or jump to the control with specified scroll_key.
• show_dialog - Displays a dialog and manages its dismissal lifecycle.
• show_drawer - Show the drawer.
• show_end_drawer - Show the end drawer.
• take_animation - Captures an animated sequence of page screenshots in a single round-trip.
• take_screenshot - Captures a screenshot of the entire page with overlays.
• update - Push pending updates to the connected client.

Properties

buildappbarpropertywritable

appbar: AppBar | CupertinoAppBar | None

Gets or sets the top application bar (AppBar or CupertinoAppBar) for the view.

The app bar typically displays the page title and optional actions such as navigation icons, menus, or other interactive elements.

buildauto_scrollpropertywritable

auto_scroll: bool

Whether root view should auto-scroll to the end on content changes.

buildbgcolorpropertywritable

bgcolor: ColorValue | None

Background color of the root view.

buildbottom_appbarpropertywritable

bottom_appbar: BottomAppBar | None

Bottom app bar displayed in the root view.

buildcontrolspropertywritable

controls: list[BaseControl]

Root view content controls displayed by this page.

builddark_themeclass-attributeinstance-attribute

dark_theme: Theme | None = None

Customizes the theme of the application when in dark theme mode.

builddecorationpropertywritable

decoration: BoxDecoration | None

Background decoration of the root view container.

builddrawerpropertywritable

drawer: NavigationDrawer | None

Navigation drawer opened from the leading edge.

buildenable_screenshotsclass-attributeinstance-attribute

enable_screenshots: bool = False

Enable taking screenshots of the entire page with take_screenshot method.

buildend_drawerpropertywritable

end_drawer: NavigationDrawer | None

Navigation drawer opened from the trailing edge.

buildfloating_action_buttonpropertywritable

floating_action_button: FloatingActionButton | None

Floating action button shown for the root view.

buildfloating_action_button_locationpropertywritable

floating_action_button_location: (
    FloatingActionButtonLocation | OffsetValue | None
)

Placement of the floating action button in the root view.

buildforeground_decorationpropertywritable

foreground_decoration: BoxDecoration | None

Foreground decoration painted above root view content.

buildheightclass-attributeinstance-attribute

height: Number | None = None

Page height in logical pixels.

Note

• This property is read-only.
• To get or set the full window height including window chrome (e.g., title bar and borders) when running a Flet app on desktop, use the Window.height property of Page.window instead.

buildhorizontal_alignmentpropertywritable

horizontal_alignment: CrossAxisAlignment

Horizontal alignment of root view child controls.

buildlocale_configurationclass-attributeinstance-attribute

locale_configuration: LocaleConfiguration | None = None

Configures supported locales and the current locale.

buildmediaclass-attributeinstance-attribute

media: PageMediaData = field(
    default_factory=lambda: PageMediaData(
        padding=Padding.zero(),
        view_padding=Padding.zero(),
        view_insets=Padding.zero(),
        device_pixel_ratio=0,
        orientation=Orientation.PORTRAIT,
        always_use_24_hour_format=False,
    )
)

The current environmental metrics of the page or window.

This data is updated whenever the platform window or layout changes, such as when rotating a device, resizing a browser window, or adjusting system UI elements like the keyboard or safe areas.

buildnavigation_barpropertywritable

navigation_bar: (
    NavigationBar | CupertinoNavigationBar | None
)

Bottom navigation bar for the root view.

buildoverlayproperty

overlay: list[BaseControl]

The list of overlay controls rendered above page content.

buildpaddingpropertywritable

padding: PaddingValue | None

Inner padding for the root view content.

buildscrollpropertywritable

scroll: ScrollMode | Scrollbar | None

Scroll behavior mode for root view content.

buildservicespropertywritable

services: list[Service]

Service instances attached to the root view lifecycle.

buildshow_semantics_debuggerclass-attributeinstance-attribute

show_semantics_debugger: bool = False

Whether to turn on an overlay that shows the accessibility information reported by the framework.

buildspacingpropertywritable

spacing: Number

Default spacing between root view child controls.

buildthemeclass-attributeinstance-attribute

theme: Theme | None = None

Customizes the theme of the application when in light theme mode. Currently, a theme can only be automatically generated from a "seed" color. For example, to generate light theme from a green color.

buildtheme_animation_styleclass-attributeinstance-attribute

theme_animation_style: AnimationStyle | None = None

Overrides the default animation style used when the application's theme is changed (for example, when theme_mode switches between light and dark).

Tip

Use AnimationStyle.no_animation to disable the theme transition entirely.

buildtheme_modeclass-attributeinstance-attribute

theme_mode: ThemeMode | None = ThemeMode.SYSTEM

The page's theme mode.

buildtitleclass-attributeinstance-attribute

title: str | None = None

Page or window title.

buildvertical_alignmentpropertywritable

vertical_alignment: MainAxisAlignment

Vertical alignment of root view child controls.

buildviewsclass-attributeinstance-attribute

views: list[View] = field(default_factory=lambda: [View()])

A list of views managed by the page.

Each View represents a distinct navigation state or screen in the application.

The first view in the list is considered the active one by default.

buildwidthclass-attributeinstance-attribute

width: Number | None = None

Page width in logical pixels.

Note

• This property is read-only.
• To get or set the full window height including window chrome (e.g., title bar and borders) when running a Flet app on desktop, use the Window.width property of Page.window instead.

Events

bolton_media_changeclass-attributeinstance-attribute

on_media_change: EventHandler[PageMediaData] | None = None

Called when media has changed.

bolton_resizeclass-attributeinstance-attribute

on_resize: EventHandler[PageResizeEvent] | None = None

Called when a user resizes a browser or native OS window containing Flet app

Example

def main(page: ft.Page):
    def handle_page_size(e):
        print("New page size:", page.window.width, page.window_height)

    page.on_resize = handle_page_size

Methods

deployed_codeadd

add(*controls: Control = ()) -> None

Adds controls to the page.

Example:

page.add(ft.Text("Hello!"), ft.FilledButton("Button"))

deployed_codeclean

clean() -> None

Remove all root view controls and send update to the client.

deployed_codeclose_drawerasync

close_drawer()

Close the drawer.

deployed_codeclose_end_drawerasync

close_end_drawer()

Close the end drawer.

deployed_codeinsert

insert(at: int, *controls: Control = ()) -> None

Inserts controls at specific index of page.controls list.

deployed_codepop_dialog

pop_dialog() -> DialogControl | None

Closes the most recently opened dialog.

This method searches the active dialog stack for the topmost dialog that is currently open, marks it as closed, updates its state, and returns the closed dialog.

Returns:

• DialogControl | None - The closed dialog instance if one was found, otherwise None.

deployed_coderemove

remove(*controls: Control = ()) -> None

Removes specific controls from page.controls list.

deployed_coderemove_at

remove_at(index: int) -> None

Remove controls from page.controls list at specific index.

deployed_codescroll_toasync

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

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

See Column.scroll_to for method details and examples.

deployed_codeshow_dialog

show_dialog(dialog: DialogControl) -> None

Displays a dialog and manages its dismissal lifecycle.

This method adds the specified dialog to the active dialog stack and renders it on the page. The DialogControl.on_dismiss handler of the dialog is temporarily wrapped to ensure the dialog is removed from the stack and its dismissal event is triggered appropriately.

Parameters:

• dialog (DialogControl) - The dialog instance to display. Must not yet be open.

Raises:

• RuntimeError - If the specified dialog is already open.

deployed_codeshow_drawerasync

show_drawer()

Show the drawer.

Raises:

• ValueError - If no drawer is defined.

deployed_codeshow_end_drawerasync

show_end_drawer()

Show the end drawer.

Raises:

• ValueError - If no end_drawer is defined.

deployed_codetake_animationasync

take_animation(
    name: str,
    frame_delays_ms: list[int],
    pixel_ratio: Number | None = None,
) -> list[bytes]

Captures an animated sequence of page screenshots in a single round-trip. Each entry in frame_delays_ms is the delay in milliseconds to wait before capturing that frame. The wait and capture loop runs entirely on the Flutter side, so animation timing isn't distorted by Python-Flutter RPC latency the way it is with a Python-driven take_screenshot loop.

Requires enable_screenshots = True.

Parameters:

• name (str) - Name prefix for the captured frames (for debugging).
• frame_delays_ms (list[int]) - Per-frame delays in milliseconds. The list length determines the number of frames captured.
• pixel_ratio (Number | None, default: None) - A pixel ratio of the captured frames. If None, device-specific pixel ratio will be used.

Returns:

• list[bytes] - List of PNG-encoded frames, one per entry in frame_delays_ms.

deployed_codetake_screenshotasync

take_screenshot(
    pixel_ratio: Number | None = None,
    delay: DurationValue | None = None,
) -> bytes

Captures a screenshot of the entire page with overlays.

Parameters:

• pixel_ratio (Number | None, default: None) - A pixel ratio of the captured screenshot. If None, device-specific pixel ratio will be used.
• delay (DurationValue | None, default: None) - A delay before taking a screenshot. The delay will be 20 milliseconds if not specified.

Returns:

• bytes - Screenshot in PNG format.

deployed_codeupdate

update(*controls: Control = ()) -> None

Push pending updates to the connected client.

Parameters:

• *controls (default: ()) - Specific controls to update. When omitted, updates this page object.