bootstack.RadioGroup#

class bootstack.RadioGroup(options=None, *, signal=None, value=None, orient='horizontal', title=None, accent=None, disabled=False, localize=None, parent=None, **kwargs)#

Bases: SelectionGroupMixin, PublicWidgetBase

A group of mutually exclusive radio buttons.

Exactly one option can be selected at a time. Options are supplied at construction via options= and can be added or removed at runtime using add() and remove().

Parameters:

  • options (list[Option] | None) – Choices for the group. Each item is a plain string (text and value are the same), a (text, value) tuple, or a {'text': ..., 'value': ...} dict — e.g. ["S", "M", "L"] or [("Small", "s"), ("Medium", "m"), ("Large", "l")]. A dict option may also carry 'icon' (a glyph rendered beside the label) and 'disabled' (when True the option is dimmed and cannot be selected); any other keys ride along as carried data on selection. An option with an 'icon' and no text — e.g. {'icon': 'star', 'value': 's'} — renders as an icon-only button.

  • signal (Signal | None) – Reactive Signal holding the selected value. When provided, value= is ignored — seed the Signal directly.

  • value (Any) – Initially selected value. Ignored when signal= is passed.

  • orient (Orient) – Layout direction. Default 'horizontal'.

  • title (str | None) – Optional label rendered above the button group.

  • accent (AccentToken | str | None) – Accent token applied to all buttons.

  • disabled (bool) – If True, all buttons are non-interactive and dimmed. Defaults to False.

  • localize (bool | Literal['auto'] | None) – Whether option labels (and the title) are translated through the catalog — True, False, or 'auto' (translate when a translation is registered, otherwise show the literal). Defaults to the app’s localize_mode. Set False to keep proper nouns untranslated; override a single option with its localize key.

  • parent (Any) – Explicit parent widget. If omitted, the current context-stack container is used.

  • **kwargs (Any) – Layout placement options applied by the parent container — fill, expand, anchor, margin, row, column, sticky. See Arranging Widgets.

property disabled: bool#

Whether all buttons in the group are non-interactive.

property is_attached: bool#

Whether the widget is currently placed in its layout.

True while the widget occupies space in its parent; False after detach (or before it has ever been placed). A detached widget keeps its state and can be returned to the layout with attach.

property schedule: Schedule#

Scheduler tied to this widget’s lifetime.

All jobs are automatically cancelled when the widget is destroyed. First access creates the Schedule instance; subsequent accesses return the same instance.

Usage:

self.schedule.delay(500, callback)
self.schedule.every(1000, tick)
job = self.schedule.idle(refresh)
job.cancel()
property selection: dict | None#

The selected option as a full record dict — the data bag — or None.

{'text': ..., 'value': ..., ...any extra keys}, indexed by key like any record. Read-only.

property text: str | None#

The label of the selected option, or None if nothing is selected.

Read-only; the display complement of value (the selection’s value).

property title: str | None#

The label rendered above the group. Assigning to it updates it live.

Set to None (or '') to remove the label entirely.

property value: Any#

The currently selected value, or None if nothing is selected.

add(label, value=None, *, icon=None, disabled=False, localize=None, **kwargs)#

Add a radio button to the group at runtime.

Parameters:

  • label (str) – Display text for the button. Pass '' with an icon for an icon-only button.

  • value (Any | None) – Value assigned when this button is selected. Defaults to label.

  • icon (Any) – Optional icon spec rendered beside the label (alone when label is blank).

  • disabled (bool) – If True, the option is dimmed and cannot be selected.

  • localize (bool | Literal['auto'] | None) – Translation mode for this option’s label, overriding the group’s localize=. Defaults to the group setting.

  • **kwargs (Any) – Further options for the rendered button, using its public parameter names. These override what add() derives from icon and disabled. text is the caption — set it with label; the group tracks its own selection.

attach(**kwargs)#

Return a detached widget to its layout, optionally moving it.

With no arguments, restores the widget to exactly where detach took it from. Any layout kwargs accepted by the original placement (e.g. fill, expand, anchor, sticky, margin) override the stored options. For stacked widgets, index= sets the position among the currently attached siblings (or pass an explicit before=/after= sibling); without one, the snapshotted position is used.

Calling attach on a widget that is already attached moves it (the kwargs are re-applied). Fires on_attach.

Parameters:

**kwargs (Any) – Layout placement options to override for this placement.

Raises:

ParentResolutionError – If the widget was never placed in a layout.

capture(path, *, inset=0, settle=0.1)#

Save a picture of this widget to an image file.

Captures the area this widget occupies on screen — one widget, a whole window, or the entire application, depending on what you call it on. The file extension selects the format, so .png, .jpg, and .pdf all work.

The widget has to be visible. A capture reads pixels from the display, so the window is brought to the front first and a hidden or detached widget cannot be captured at all. Any always-on-top setting the window already had is left as it was found.

Pair it with a save dialog to let the user choose where it goes:

import bootstack as bs

def on_export():
    chosen = bs.ask_save_file(initial_file="dashboard.png")
    if chosen:
        app.capture(chosen)
Parameters:

  • path (str | Path) – Where to write the image. Missing parent folders are created, and the extension chooses the format.

  • inset (int) – Pixels to trim from every edge, zero or more. Use 2 on a whole window to drop the native border artifact.

  • settle (float) – Seconds to let the desktop finish repainting before the pixels are read. The default covers the common case of a dialog closing just beforehand. The interface pauses for this long, so a second click on the control that started the capture waits its turn rather than starting an overlapping one.

Returns:

The path that was written.

Raises:

BootstackError – If the widget is not visible on screen or has been scrolled out of view, if inset is negative, if no capture backend is available, or if the file cannot be written.

Return type:

Path

Added in version 0.3.0.

configure_item(value, *, label=None, disabled=None)#

Update a single option in place, without rebuilding the group.

Parameters:

  • value (Any) – The option to update (the value it was added with).

  • label (str | None) – New display text, when given.

  • disabled (bool | None) – When given, disable (True) or re-enable (False) just this option. A later group-level disabled change resets every option’s state, so apply per-option states after it.

Raises:

KeyError – If no option with that value exists.

destroy()#

Destroy the widget and release the resources it holds.

Removes the widget from its parent, destroys its children, and cancels any pending or repeating jobs on its schedule. After this the widget must not be used again. Destroying a container destroys everything inside it.

detach()#

Remove the widget from its layout without destroying it.

The widget stops occupying space but keeps its state, children, and event bindings, ready to be returned with attach. The current position is snapshotted so a plain attach() restores it exactly — for stacked siblings this is the index among the currently attached siblings, so detaching other siblings first shifts that index.

Calling detach on a widget that is already detached, or one that was never placed in a layout, does nothing. Fires on_detach.

emit(event, *, data=None)#

Fire a named event on this widget, as if it produced the event itself.

This is how a composite widget surfaces high-level activity to its listeners, and the generic counterpart to the on_*() shorthands for firing events that have no dedicated method.

It is meant for the framework’s own events — 'change', 'select', 'input' and the rest of the data-carrying names. A handler registered through on() or an on_<event>() shorthand receives what is emitted.

Names that map onto a native event instead ('click', 'focus', 'blur', 'submit', …) are a different matter: emitting one asks the toolkit to deliver a real input event, which carries no payload and can reach handlers the widget installed for its own use. Emitting those is not a way to notify listeners, and a listener bound through on() may not see it. Drive the widget through its properties and methods instead.

Parameters:

  • event (str) – The event name, unprefixed — the same name you pass to on() or an on_<event>() shorthand (e.g. 'change', 'select').

  • data (Any) – The payload delivered to handlers. Pass the matching payload dataclass from bootstack.events — the same object an on_<event>() handler receives.

Example

from bootstack.events import ChangeEvent

field.emit("change", data=ChangeEvent(value=new_value))
on(event, handler=None)#

Bind handler to event, or return a composable Stream.

With a handler — binds immediately and returns a Subscription:

sub = widget.on("change", handler)
sub.cancel()

Without a handler — returns a Stream for operator chaining. The Tk binding is created lazily when .listen() is called:

sub = widget.on("change").debounce(300).listen(handler)
sub.cancel()
Parameters:

  • event (str) – Event name (e.g. "change", "click").

  • handler (Callable[[Any], Any] | None) – Optional callback. If omitted, a Stream is returned.

Returns:

Subscription when a handler is provided; Stream otherwise.

Return type:

Stream | Subscription

on_attach(handler=None)#

Register a callback fired when the widget enters the layout.

Fires each time the widget becomes visible in its parent — on initial placement and on every attach. Pair it with on_detach to keep per-visibility resources (timers, observers) tied to the widget’s presence on screen. The handler receives a curated Event.

Parameters:

handler (Callable[[Event], Any] | None) – Called when the widget is attached. Omit to get a composable Stream.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

on_change() → Stream#
on_change(handler: Callable[[ChangeEvent], Any]) → Subscription

Register a callback fired whenever the selection changes.

Parameters:

handler (Callable[[ChangeEvent], Any] | None) – Called with a ChangeEvent; the selected value is also available via group.value. Omit to get a composable Stream instead.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

on_destroy(handler=None)#

Register a callback fired when the widget is destroyed.

Fires once, as the widget is torn down — the place to release resources the widget owns that aren’t cleaned up automatically (file handles, observers, external subscriptions). The handler receives a curated Event.

Parameters:

handler (Callable[[Event], Any] | None) – Called as the widget is destroyed. Omit to get a composable Stream.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

on_detach(handler=None)#

Register a callback fired when the widget leaves the layout.

Fires each time the widget stops occupying space in its parent — on detach and when an ancestor hides it. Pair it with on_attach to release per-visibility resources. The handler receives a curated Event.

Parameters:

handler (Callable[[Event], Any] | None) – Called when the widget is detached. Omit to get a composable Stream.

Returns:

A cancellable Subscription when a handler is given, otherwise a Stream.

Return type:

Stream | Subscription

remove(value)#

Remove the option identified by value.

Parameters:

value (Any) – The value the option was added with.

Raises:

KeyError – If no option with that value exists.