com.facebook.rendercore

Interface Node<RenderContext>

All Known Implementing Classes:

LithoNode, Mountable, NestedTreeHolder

public interface Node<RenderContext>

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	LayoutResult Represents the result of a Layout pass.

Method Summary

Modifier and Type	Method and Description
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.

Method Detail

calculateLayout

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