com.facebook.rendercore

Class Mountable<ContentT>

java.lang.Object

com.facebook.rendercore.RenderUnit<ContentT>

com.facebook.rendercore.Mountable<ContentT>

Type Parameters:

ContentT - The type of the content.

All Implemented Interfaces:

Node

public abstract class Mountable<ContentT>
extends RenderUnit<ContentT>
implements Node

A Mountable represents a rendering primitive.

Every Mountable must define what content it creates via the ContentAllocator implementation, and its type. It must also implement a mechanism to measure itself given arbitrary width and height specs. A Mountable can also specify a collection of Binders to set and unset properties on the content via RenderUnit's addMountBinder and addAttachBinder methods.

Experimental. Currently for Litho team internal use only.

• A Mountable must only create one type of content.
• A Mountable must be immutable.
• Content properties must be unset otherwise the content will not match expected behaviour when they are reused from the content pool.

See Also:

RenderUnit, Node

Nested Class Summary

Nested classes/interfaces inherited from class com.facebook.rendercore.RenderUnit

RenderUnit.Binder<MODEL,CONTENT>, RenderUnit.DelegateBinder<MODEL,CONTENT>, RenderUnit.RenderType

Nested classes/interfaces inherited from interface com.facebook.rendercore.Node

LayoutResult

Constructor Summary

Constructors

Constructor and Description
Mountable(RenderUnit.RenderType renderType)

Method Summary

Modifier and Type	Method and Description
void	attachBinders(Context context, java.lang.Object content, java.lang.Object layoutData, Systracer tracer) This method is an override that calls super impl to keep it protected on RenderUnit.
LayoutResult	calculateLayout(RenderState.LayoutContext context, int widthSpec, int heightSpec) Implementations of Node are responsible to calculate a layout based on the width/height constraints provided.
void	detachBinders(Context context, java.lang.Object content, java.lang.Object layoutData, Systracer tracer) This method is an override that calls super impl to keep it protected on RenderUnit.
java.util.List<RenderUnit.DelegateBinder<?,ContentT>>	getAttachBinders() This method is an override that calls super impl to keep it protected on RenderUnit.
java.util.Map<java.lang.Class<?>,RenderUnit.DelegateBinder<?,ContentT>>	getAttachBinderTypeToDelegateMap() This method is an override that calls super impl to keep it protected on RenderUnit.
long	getId()
java.util.List<RenderUnit.DelegateBinder<?,ContentT>>	getMountBinders() This method is an override that calls super impl to keep it protected on RenderUnit.
java.util.Map<java.lang.Class<?>,RenderUnit.DelegateBinder<?,ContentT>>	getMountBinderTypeToDelegateMap() This method is an override that calls super impl to keep it protected on RenderUnit.
RenderUnit.RenderType	getRenderType()
protected abstract MeasureResult	measure(RenderState.LayoutContext context, int widthSpec, int heightSpec, java.lang.Object previousLayoutData) Given a and set the width and height this Mountable will require on MeasureResult.
void	mountBinders(Context context, java.lang.Object contentT, java.lang.Object layoutData, Systracer tracer) This method is an override that calls super impl to keep it protected on RenderUnit.
void	setId(long id)
void	unmountBinders(Context context, java.lang.Object contentT, java.lang.Object layoutData, Systracer tracer) This method is an override that calls super impl to keep it protected on RenderUnit.

Methods inherited from class com.facebook.rendercore.RenderUnit

addAttachBinder, addAttachBinders, addMountBinder, addMountBinders, doesMountRenderTreeHosts, getContentAllocator, getDescription, getRenderContentType, onEndUpdateRenderUnit, onStartUpdateRenderUnit

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Mountable

public Mountable(RenderUnit.RenderType renderType)

Method Detail

setId

public final void setId(long id)

getId

public final long getId()

Specified by:

getId in class RenderUnit<ContentT>

Returns:

a unique id identifying this RenderUnit in the tree of Node it is part of.

getRenderType

public final RenderUnit.RenderType getRenderType()

Overrides:

getRenderType in class RenderUnit<ContentT>

calculateLayout

public final LayoutResult calculateLayout(RenderState.LayoutContext context,
                                               int widthSpec,
                                               int heightSpec)

Description copied from interface: Node

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.

Specified by:

calculateLayout in interface Node

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

measure

protected abstract MeasureResult measure(RenderState.LayoutContext context,
                                         int widthSpec,
                                         int heightSpec,
                                         java.lang.Object previousLayoutData)

Given a and set the width and height this Mountable will require on MeasureResult. In addition on MeasureResult you can put any data that is required to set, and unset properties on the content in the binders.

If measure is called again in the same layout pass, then will be the layout data returned by the previous measure call.

As a performance optimisation the framework will skip this method if this Mountable is equal to the previous Mountable, and if the size specs are compatible. In order to do this the framework will check if every field of the Mountable is equal using reflection.

• Must not cause side effects.
• Is guaranteed to be called at least once.
• Can be called more that once.
• Can be called from any thread.

Returns:

a MeasureResult with the width, height, and optional layout data.

mountBinders

public final void mountBinders(Context context,
                               java.lang.Object contentT,
                               java.lang.Object layoutData,
                               Systracer tracer)

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

mountBinders in class RenderUnit<ContentT>

unmountBinders

public final void unmountBinders(Context context,
                                 java.lang.Object contentT,
                                 java.lang.Object layoutData,
                                 Systracer tracer)

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

unmountBinders in class RenderUnit<ContentT>

attachBinders

public final void attachBinders(Context context,
                                java.lang.Object content,
                                java.lang.Object layoutData,
                                Systracer tracer)

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

attachBinders in class RenderUnit<ContentT>

detachBinders

public final void detachBinders(Context context,
                                java.lang.Object content,
                                java.lang.Object layoutData,
                                Systracer tracer)

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

detachBinders in class RenderUnit<ContentT>

getMountBinderTypeToDelegateMap

public final java.util.Map<java.lang.Class<?>,RenderUnit.DelegateBinder<?,ContentT>> getMountBinderTypeToDelegateMap()

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

getMountBinderTypeToDelegateMap in class RenderUnit<ContentT>

getMountBinders

public final java.util.List<RenderUnit.DelegateBinder<?,ContentT>> getMountBinders()

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

getMountBinders in class RenderUnit<ContentT>

getAttachBinderTypeToDelegateMap

public final java.util.Map<java.lang.Class<?>,RenderUnit.DelegateBinder<?,ContentT>> getAttachBinderTypeToDelegateMap()

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

getAttachBinderTypeToDelegateMap in class RenderUnit<ContentT>

getAttachBinders

public final java.util.List<RenderUnit.DelegateBinder<?,ContentT>> getAttachBinders()

This method is an override that calls super impl to keep it protected on RenderUnit.

Overrides:

getAttachBinders in class RenderUnit<ContentT>