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NavigationBar

Examples#

Live example

Basic Example#

import flet as ft


def main(page: ft.Page):
    page.title = "NavigationBar Example"

    page.navigation_bar = ft.NavigationBar(
        destinations=[
            ft.NavigationBarDestination(icon=ft.Icons.EXPLORE, label="Explore"),
            ft.NavigationBarDestination(icon=ft.Icons.COMMUTE, label="Commute"),
            ft.NavigationBarDestination(
                icon=ft.Icons.BOOKMARK_BORDER,
                selected_icon=ft.Icons.BOOKMARK,
                label="Favorites",
            ),
        ]
    )

    page.add(ft.Text("Body!"))


ft.run(main)

basic

NavigationBar #

Bases: ConstrainedControl, AdaptiveControl

Material 3 Navigation Bar component.

Navigation bars offer a persistent and convenient way to switch between primary destinations in an app.

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

animation_duration #

animation_duration: DurationValue | None = None

The transition time for each destination as it goes between selected and unselected.

aspect_ratio #

aspect_ratio: Number | None = None

TBD

badge #

badge: BadgeValue | None = None

A badge to show on top of this control.

bgcolor #

bgcolor: ColorValue | None = None

The color of the navigation bar itself.

border #

border: Border | None = None

TBD

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.

destinations #

destinations: list[NavigationBarDestination] = field(
    default_factory=list
)

Defines the appearance of the button items that are arrayed within the navigation bar.

The value must be a list of two or more NavigationBarDestination instances.

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()
    ]
)

elevation #

elevation: Number | None = None

The elevation of the navigation bar itself.

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.

height #

height: Number | None = None

Imposed Control height in virtual pixels.

indicator_color #

indicator_color: ColorValue | None = None

The color of the selected destination indicator.

indicator_shape #

indicator_shape: OutlinedBorder | None = None

The shape of the selected destination indicator.

key #

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

label_behavior #

label_behavior: NavigationBarLabelBehavior | None = None

Defines how the destinations' labels will be laid out and when they'll be displayed.

Can be used to show all labels, show only the selected label, or hide all labels.

Defaults to NavigationBarLabelBehavior.ALWAYS_SHOW.

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.

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_change #

on_change: ControlEventHandler[NavigationBar] | None = None

Called when selected destination changed.

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 highlight color of the NavigationDestination in various ControlState states.

The following ControlState values are supported: PRESSED, HOVERED and FOCUSED.

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)
)

selected_index #

selected_index: int = 0

The index into destinations for the current selected NavigationBarDestination or None if no destination is selected.

shadow_color #

shadow_color: ColorValue | None = None

The color used for the drop shadow to indicate elevation.

surface_tint_color #

surface_tint_color: ColorValue | None = None

The surface tint of the Material that holds the NavigationDrawer's contents.

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.

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()

clean #

clean() -> None

did_mount #

did_mount()

init #

init()

is_isolated #

is_isolated()

update #

update() -> None

will_unmount #

will_unmount()