com.facebook.rendercore

Interface Node<RenderContext>

All Superinterfaces:

java.lang.Cloneable, Copyable

All Known Subinterfaces:

InternalNode

All Known Implementing Classes:

DefaultInternalNode

public interface Node<RenderContext>
extends Copyable

Represents a single node in a RenderCore Tree. A Node has children, base layout information, and whether it needs to be rendered.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Node.LayoutResult<T> Represents the result of a Layout pass.

Method Summary

Modifier and Type	Method and Description
Node.LayoutResult	calculateLayout(RenderState.LayoutContext<RenderContext> context, int widthSpec, int heightSpec) Implementations of Node are responsible to calculate a layout based on the width/height constraints provided.
Copyable	getLayoutParams() Returns the layout params of this Node.

Methods inherited from interface com.facebook.rendercore.Copyable

makeCopy

Method Detail

calculateLayout

Node.LayoutResult calculateLayout(RenderState.LayoutContext<RenderContext> context,
                                  int widthSpec,
                                  int heightSpec)

Implementations of Node are responsible to calculate a layout based on the width/height constraints provided. A Node could decide to implement its own layout function or to delegate to its RenderUnit measure.

The general contract is:
• - A Node must call calculateLayout on each child (if it has any) at least once, even if the Node is going to assign that child an exact size -- this gives a chance for children to lay out their own children and produce artifacts like text layouts.
• - If a Node calls layout on a child with flexible specs (UNSPECIFIED or AT_MOST) to get sizing information, but ultimately decides to assign that child a different size than the child returned, the Node must call calculateLayout again on that child with a mode of EXACTLY to enforce the assigned size.

Parameters:

context - The LayoutContext associated with this layout calculation RenderState.LayoutContext

widthSpec - a measure spec for the width in the format of View.MeasureSpec

heightSpec - a measure spec for the height in the format of View.MeasureSpec

getLayoutParams

Copyable getLayoutParams()

Returns the layout params of this Node. The layout params are useful to inform the parent of this node, about how this Node should be laid-out. The layout params implement Copyable, and can be copied to be reused but another node.

Returns:

the layout params for this Node.