Select

Select, declared in <huxerui/view.h>, is a non-editable choice field. Use ComboBox when the user should also type.

Keep selection controlled

#include <huxerui/huxerui.h>

#include <cstddef>
#include <string>
#include <vector>

using namespace huxerui;

[[huxerui::composable]]
View SortField() {
  auto selected = UseState<std::size_t>(0);
  return Select(std::vector<std::string>{"Name", "Date", "Size"}, selected,
      [](const std::string& label) { return Text(label).Key(label); })
      .Label("Sort by")
      .OnChanged([selected](std::size_t index) { selected = index; });
}

The selected index and item range may be plain values or State values. OnChanged(std::size_t) proposes a new index; ignoring it leaves the controlled selection unchanged. Keep the index valid when changing the source. The item factory defines content used by the control, not a second independently interactive button.

API and styling

• Select(items, selected_index, content_factory) accepts an input range or a state-held range.
• .Label(StringVariant) supplies the field’s label.
• .Validation(ValidationResult) reports application-owned validation.
• .OnChanged(handler) writes accepted choices back to the owner.
• SelectStyle is resolved by the theme.

Give dynamic rows stable sibling keys. Selection remains positional, so preserve the selected item’s meaning when sorting or replacing the range.

The field shares keyboard, popup dismissal, focus, and accessibility behavior with the framework. Use Menu for commands rather than a persistent selected value.

Item and keyboard contracts

The four constructor families pair a plain range or State<Range> with a plain std::size_t or State<std::size_t>, followed by the same View(item) factory. The source captures an owned snapshot for that declaration; update the range through recomposition. The selected index is positional, even when rows have stable keys.

Each returned row root needs a nonempty semantic label. Text provides one naturally; for compound Row content set Semantics{.label = item_name} on that root. Enabled(false) on a row makes that choice unavailable. The row must not contain independent buttons, text editors, or competing pointer handlers: Select supplies its choice activation.

Up/Down navigate enabled popup choices; Home/End reach the enabled edges; Enter/Space accepts the active choice. Navigation highlight is transient and does not change the controlled selected index until acceptance. Dismissal leaves the current selection intact. Label supplies the field’s accessible name and Validation shows domain feedback without disabling choices.

SelectStyle fields

Fields	Effect
background, foreground, border, indicator	Trigger surface, content, outline, and dropdown marker.
popup_background, active_item_background, selected_item_background	Popup surface, keyboard highlight, and controlled selected state.
trigger_padding, item_padding, popup_padding, content_spacing	Spacing for each level.
minimum_width, minimum_height, minimum_item_height, maximum_popup_height	Preferred trigger size and bounded scrolling popup.
indicator_size, corner_radii, popup_corner_radii, popup_shadow	Marker and surface geometry.
validation_error, validation_text_style, validation_spacing	Domain error presentation.
indication, item_indication	Trigger and choice interaction visuals.

Material and Flat provide independent field and popup styles. To fit a toolbar, override the relevant padding/minimums together; shrinking the label alone does not shrink the interactive rows.

Observe popup visibility

OnExpandedChanged(bool) reports a successful opening or the start of closing. It does not report exit-animation completion or a canceled opening attempt. Initial mount and destruction do not emit it. Selecting another option emits closing before OnChanged.

This is observation of the component’s popup, not a second controlled Open property. Use it for surrounding UI policy; do not treat it as value selection or teardown cleanup.