Struct zng_app::widget::node::ArcNode

pub struct ArcNode<U: UiNode>(/* private fields */);

A reference counted UiNode.

Nodes can only be used in one place at a time, this struct allows the creation of slots that are UiNode implementers that can exclusive take the referenced node as its child.

When a slot takes the node it is deinited in the previous place and reinited in the slot place.

Slots hold a strong reference to the node when they have it as their child and a weak reference when they don’t.

Implementations

impl<U: UiNode> ArcNode<U>

pub fn new(node: U) -> Self

New node.

pub fn new_cyclic(node: impl FnOnce(WeakNode<U>) -> U) -> Self

New node that contains a weak reference to itself.

Note that the weak reference cannot be upgraded during the call to node.

pub fn downgrade(&self) -> WeakNode<U>

Creates a WeakNode<U> reference to this node.

pub fn set(&self, new_node: U)

Replace the current node with the new_node in the current slot.

The previous node is deinited and the new_node is inited.

pub fn take_when(&self, var: impl IntoVar<bool>) -> TakeSlot<U, impl TakeOn>

Create a slot node that takes ownership of this node when var updates to true.

The slot node also takes ownership on init if the var is already true.

pub fn take_on<A: EventArgs>( &self, event: Event<A>, filter: impl FnMut(&A) -> bool + Send + 'static, take_on_init: bool, ) -> TakeSlot<U, impl TakeOn>

Create a slot node that takes ownership of this node when event updates and filter returns true.

The slot node also takes ownership on init if take_on_init is true.

pub fn take_on_init(&self) -> TakeSlot<U, impl TakeOn>

Create a slot node that takes ownership of this node as soon as the node is inited.

This is equivalent to self.take_when(true).

pub fn try_context<R>( &self, update_mode: WidgetUpdateMode, f: impl FnOnce() -> R, ) -> Option<R>

Calls f in the context of the node, if it can be locked and is a full widget.

Trait Implementations

impl<U: UiNode> Clone for ArcNode<U>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.