com.facebook.litho.widget

Interface LayoutInfo

All Superinterfaces:

ViewportInfo

All Known Implementing Classes:

GridLayoutInfo, LinearLayoutInfo, StaggeredGridLayoutInfo

public interface LayoutInfo
extends ViewportInfo

An implementation of this interface will provide the RecyclerBinder with all the information about the RecyclerView layout.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	LayoutInfo.RenderInfoCollection
static interface	LayoutInfo.ViewportFiller Interface that is responsible for filling the viewport of the list with initial layouts according to the LayoutManager.

Nested classes/interfaces inherited from interface com.facebook.litho.widget.ViewportInfo

ViewportInfo.State, ViewportInfo.ViewportChanged

Method Summary

Modifier and Type	Method and Description
int	approximateRangeSize(int firstMeasuredItemWidth, int firstMeasuredItemHeight, int recyclerMeasuredWidth, int recyclerMeasuredHeight) This is called when the RecyclerBinder needs to calculate a range size.
int	computeWrappedHeight(int maxHeight, List<ComponentTreeHolder> componentTreeHolders)
LayoutInfo.ViewportFiller	createViewportFiller(int measuredWidth, int measuredHeight)
int	getChildHeightSpec(int heightSpec, RenderInfo renderInfo)
int	getChildWidthSpec(int widthSpec, RenderInfo renderInfo)
LayoutManager	getLayoutManager()
int	getScrollDirection() This is the main scrolling direction that the LayoutManager passed to this binder will use.
void	scrollToPositionWithOffset(int position, int offset) RecyclerBinder delegates scrolling responsibilities to the LayoutInfo, as the varied LayoutManagers wrapped by a LayoutInfo lack a common scrolling interface.
void	setRenderInfoCollection(LayoutInfo.RenderInfoCollection renderInfoCollection)

Methods inherited from interface com.facebook.litho.widget.ViewportInfo

findFirstFullyVisibleItemPosition, findFirstVisibleItemPosition, findLastFullyVisibleItemPosition, findLastVisibleItemPosition, getItemCount

Method Detail

getScrollDirection

int getScrollDirection()

This is the main scrolling direction that the LayoutManager passed to this binder will use.

Returns:

either OrientationHelper#HORIZONTAL or OrientationHelper#VERTICAL.

getLayoutManager

LayoutManager getLayoutManager()

Returns:

The LayoutManager to be used with the RecyclerView.

setRenderInfoCollection

void setRenderInfoCollection(LayoutInfo.RenderInfoCollection renderInfoCollection)

Parameters:

renderInfoCollection -

scrollToPositionWithOffset

void scrollToPositionWithOffset(int position,
                                int offset)

RecyclerBinder delegates scrolling responsibilities to the LayoutInfo, as the varied LayoutManagers wrapped by a LayoutInfo lack a common scrolling interface. Typical implementations should forward the call to the underlying LayoutManager's scrollToPositionWithOffset() or an equivalent.

Parameters:

position - Index of the item in the adapter

offset - Additional adjustment to control the precise position the scroll moves to.

approximateRangeSize

int approximateRangeSize(int firstMeasuredItemWidth,
                         int firstMeasuredItemHeight,
                         int recyclerMeasuredWidth,
                         int recyclerMeasuredHeight)

This is called when the RecyclerBinder needs to calculate a range size. The returned value should be an approximate range size based on the size of the first measured item.

Parameters:

firstMeasuredItemWidth - The width of the first item measured while computing the range.

firstMeasuredItemHeight - The height of the first item measured while computing the range.

recyclerMeasuredWidth - The measured width of the RecyclerView. If the RecyclerView scrolls vertically this might be not significant.

recyclerMeasuredHeight - The measured height of the RecyclerView. If the RecyclerView scrolls horizontally this might be not significant.

Returns:

The estimated number of items that are needed to fill one viewport of the RecyclerView.

getChildWidthSpec

int getChildWidthSpec(int widthSpec,
                      RenderInfo renderInfo)

Parameters:

widthSpec - the widthSpec used to measure the parent RecyclerSpec.

renderInfo - retrieve SpanSize of the component if it is a GridLayoutInfo

Returns:

the widthSpec to be used to measure the size of the components within this RecyclerBinder.

getChildHeightSpec

int getChildHeightSpec(int heightSpec,
                       RenderInfo renderInfo)

Parameters:

heightSpec - the heightSpec used to measure the parent RecyclerSpec.

renderInfo - retrieve SpanSize of the component if it is a GridLayoutInfo

Returns:

the heightSpec to be used to measure the size of the components within this RecyclerBinder.

createViewportFiller

LayoutInfo.ViewportFiller createViewportFiller(int measuredWidth,
                                               int measuredHeight)

Parameters:

measuredWidth - the width of the RecyclerView

measuredHeight - the height of the RecyclerView

Returns:

a LayoutInfo.ViewportFiller to fill the RecyclerView viewport with views, or null to not pre-fill the RecyclerView.

computeWrappedHeight

int computeWrappedHeight(int maxHeight,
                         List<ComponentTreeHolder> componentTreeHolders)

Parameters:

maxHeight - the max height of the parent RecyclerSpec.

componentTreeHolders - the list of ComponentTreeHolder in this RecyclerBinder.

Returns:

the measured height of this RecyclerBinder.