NavigationBarLabelBehavior 继承自： Enum

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

示例

import flet as ft


def showcase_card(behavior: ft.NavigationBarLabelBehavior) -> ft.Container:
    bar = ft.NavigationBar(
        label_behavior=behavior,
        selected_index=1,
        destinations=[
            ft.NavigationBarDestination(icon=ft.Icons.HOME, label="Home"),
            ft.NavigationBarDestination(icon=ft.Icons.SEARCH, label="Search"),
            ft.NavigationBarDestination(icon=ft.Icons.PERSON, label="Profile"),
        ],
    )

    return ft.Container(
        width=380,
        padding=12,
        border=ft.Border.all(1, ft.Colors.RED),
        border_radius=10,
        bgcolor=ft.Colors.SURFACE_CONTAINER_LOW,
        content=ft.Column(
            spacing=8,
            controls=[
                ft.Text(behavior.name, weight=ft.FontWeight.BOLD),
                bar,
            ],
        ),
    )


def main(page: ft.Page):
    page.horizontal_alignment = ft.CrossAxisAlignment.CENTER

    page.appbar = ft.AppBar(title="NavigationBarLabelBehavior Showcase")
    page.add(
        ft.SafeArea(
            content=ft.Column(
                controls=[
                    ft.Text("Compare destination label visibility strategies."),
                    ft.Row(
                        wrap=True,
                        spacing=12,
                        expand=True,
                        scroll=ft.ScrollMode.AUTO,
                        alignment=ft.MainAxisAlignment.CENTER,
                        controls=[
                            showcase_card(behavior)
                            for behavior in ft.NavigationBarLabelBehavior
                        ],
                    ),
                ],
            ),
        )
    )


if __name__ == "__main__":
    ft.run(main)

枚举值

名称	类型	默认值	说明
ALWAYS_SHOW	—	'alwaysShow'	Always shows the label below every destination, selected and unselected.
ALWAYS_HIDE	—	'alwaysHide'	Hides every destination label, regardless of which destination is selected.
ONLY_SHOW_SELECTED	—	'onlyShowSelected'	Shows the label only for the selected destination. Unselected destinations hide their labels and keep the icon centered. When a destination becomes selected, its label fades in and the label/icon pair shifts so both remain centered together.