Struct conrod::widget::list::List

pub struct List {
    pub common: CommonBuilder,
    pub style: Style,
    pub item_instantiation: ItemInstantiation,
    // some fields omitted
}

A helper widget, useful for instantiating a sequence of widgets in a vertical list.

The List widget simplifies this process by:

• Generating widget::Ids.
• Simplifying the positioning and sizing of items.
• Optimised widget instantiation by only instantiating visible items. This is very useful for lists containing many items, i.e. a FileNavigator over a directory with thousands of files.

Fields

common: CommonBuilder

Common widget building params for the List.

style: Style

Unique styling for the List.

item_instantiation: ItemInstantiation

Whether all or only visible items should be instantiated.

Methods

impl List

pub fn new(num_items: usize, item_height: Scalar) -> Self

Create a List context to be built upon.

pub fn scrollbar_next_to(self) -> Self

Specifies that the List should be scrollable and should provide a Scrollbar to the right of the items.

pub fn scrollbar_on_top(self) -> Self

Specifies that the List should be scrollable and should provide a Scrollbar that hovers above the right edge of the items and automatically hides when the user is not scrolling.

pub fn scrollbar_width(self, w: Scalar) -> Self

The width of the Scrollbar.

pub fn scrollbar_color(self, color: Color) -> Self

The color of the Scrollbar.

pub fn instantiate_all_items(self) -> Self

Indicates that an Item should be instatiated for every element in the list, regardless of whether or not the Item would be visible.

Note: This may cause significantly heavier CPU load for lists containing many items (100+). We only recommend using this when absolutely necessary as large lists may cause unnecessary bloating within the widget graph, and in turn result in greater traversal times.

pub fn instantiate_only_visible_items(self) -> Self

Indicates that only Items that are visible should be instantiated. This ensures that we avoid bloating the widget graph with unnecessary nodes and in turn keep traversal times to a minimum.

This is the default List behaviour.

Trait Implementations

impl Clone for List

fn clone(&self) -> List

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Widget for List

type State = State

State to be stored within the Uis widget cache.

type Style = Style

Every widget is required to have its own associated Style type. This type is intended to contain high-level styling information for the widget that can be optionally specified by a user of the widget.

type Event = (Items, Option<Scrollbar>)

The type of event yielded by the widget, returned via the Widget::set function.

fn common(&self) -> &CommonBuilder

Return a reference to a CommonBuilder struct owned by the Widget. This method allows us to do a blanket impl of Positionable and Sizeable for T: Widget.

fn common_mut(&mut self) -> &mut CommonBuilder

Return a mutable reference to a CommonBuilder struct owned by the Widget. This method allows us to do a blanket impl of Positionable and Sizeable for T: Widget.

fn init_state(&self, id_gen: Generator) -> Self::State

Return the initial State of the Widget.

fn style(&self) -> Self::Style

Return the styling of the widget.

fn update(self, args: UpdateArgs<Self>) -> Self::Event

Update our Widget's unique Widget::State via the State wrapper type (the state field within the UpdateArgs).

fn default_x_position(&self, ui: &Ui) -> Position

The default Position for the widget along the x axis.

fn default_y_position(&self, ui: &Ui) -> Position

The default Position for the widget along the y axis.

fn default_x_dimension(&self, ui: &Ui) -> Dimension

The default width for the Widget.

fn default_y_dimension(&self, ui: &Ui) -> Dimension

The default height of the widget.

fn drag_area(
    &self,
    _dim: Dimensions,
    _style: &Self::Style,
    _theme: &Theme
) -> Option<Rect>

If the widget is draggable, implement this method and return the position and dimensions of the draggable space. The position should be relative to the center of the widget.

fn kid_area(&self, args: KidAreaArgs<Self>) -> KidArea

The area on which child widgets will be placed when using the Place Position methods.

fn parent(self, parent_id: Id) -> Self

Set the parent widget for this Widget by passing the WidgetId of the parent.

fn no_parent(self) -> Self

Specify that this widget has no parent widgets.

fn place_on_kid_area(self, b: bool) -> Self

Set whether or not the Widget should be placed on the kid_area.

fn graphics_for(self, id: Id) -> Self

Indicates that the Widget is used as a non-interactive graphical element for some other widget.

fn floating(self, is_floating: bool) -> Self

Set whether or not the widget is floating (the default is false). A typical example of a floating widget would be a pop-up or alert window.

fn crop_kids(self) -> Self

Indicates that all widgets who are children of this widget should be cropped to the kid_area of this widget.

fn scroll_kids(self) -> Self

Makes the widget's KidArea scrollable.

fn scroll_kids_vertically(self) -> Self

Makes the widget's KidArea scrollable.

fn scroll_kids_horizontally(self) -> Self

Set whether or not the widget's KidArea is scrollable (the default is false).

fn and<F>(self, build: F) -> Self where
    F: FnOnce(Self) -> Self, 

A builder method that "lifts" the Widget through the given build function.

fn and_mut<F>(self, mutate: F) -> Self where
    F: FnOnce(&mut Self), 

A builder method that mutates the Widget with the given mutate function.

fn and_if<F>(self, cond: bool, build: F) -> Self where
    F: FnOnce(Self) -> Self, 

A method that conditionally builds the Widget with the given build function.

fn and_then<T, F>(self, maybe: Option<T>, build: F) -> Self where
    F: FnOnce(Self, T) -> Self, 

A method that optionally builds the the Widget with the given build function.

fn set<'a, 'b>(self, id: Id, ui_cell: &'a mut UiCell<'b>) -> Self::Event

Note: There should be no need to override this method.