com.facebook.litho.widget

Class StaggeredGridLayoutInfo

java.lang.Object

com.facebook.litho.widget.StaggeredGridLayoutInfo

All Implemented Interfaces:

LayoutInfo, ViewportInfo

public class StaggeredGridLayoutInfo
extends Object
implements LayoutInfo

An implementation for LayoutInfo to implement staggered grids with a StaggeredGridLayoutManager.

Nested Class Summary

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

LayoutInfo.RenderInfoCollection

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

ViewportInfo.State, ViewportInfo.ViewportChanged

Field Summary

Fields

Modifier and Type	Field and Description
static String	OVERRIDE_SIZE

Constructor Summary

Constructors

Constructor and Description
StaggeredGridLayoutInfo(int spanCount, int orientation, boolean reverseLayout, int gapStrategy)
StaggeredGridLayoutInfo(int spanCount, int orientation, boolean reverseLayout, int gapStrategy, boolean eagerlyClearsSpanAssignmentsOnUpdates, boolean invalidatesItemDecorationsOnUpdates)

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)
com.facebook.litho.widget.StaggeredGridLayoutInfo.ViewportFiller	createViewportFiller(int measuredWidth, int measuredHeight)
int	findFirstFullyVisibleItemPosition()
int	findFirstVisibleItemPosition()
int	findLastFullyVisibleItemPosition()
int	findLastVisibleItemPosition()
int	getChildHeightSpec(int heightSpec, RenderInfo renderInfo)
int	getChildWidthSpec(int widthSpec, RenderInfo renderInfo)
int	getItemCount()
RecyclerView.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 class java.lang.Object

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

Field Detail

OVERRIDE_SIZE

public static final String OVERRIDE_SIZE

See Also:

Constant Field Values

Constructor Detail

StaggeredGridLayoutInfo

public StaggeredGridLayoutInfo(int spanCount,
                               int orientation,
                               boolean reverseLayout,
                               int gapStrategy)

StaggeredGridLayoutInfo

public StaggeredGridLayoutInfo(int spanCount,
                               int orientation,
                               boolean reverseLayout,
                               int gapStrategy,
                               boolean eagerlyClearsSpanAssignmentsOnUpdates,
                               boolean invalidatesItemDecorationsOnUpdates)

Method Detail

getScrollDirection

public int getScrollDirection()

Description copied from interface: LayoutInfo

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

Specified by:

getScrollDirection in interface LayoutInfo

Returns:

either OrientationHelper#HORIZONTAL or OrientationHelper#VERTICAL.

getLayoutManager

public RecyclerView.LayoutManager getLayoutManager()

Specified by:

getLayoutManager in interface LayoutInfo

Returns:

The LayoutManager to be used with the RecyclerView.

setRenderInfoCollection

public void setRenderInfoCollection(LayoutInfo.RenderInfoCollection renderInfoCollection)

Specified by:

setRenderInfoCollection in interface LayoutInfo

scrollToPositionWithOffset

public void scrollToPositionWithOffset(int position,
                                       int offset)

Description copied from interface: LayoutInfo

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.

Specified by:

scrollToPositionWithOffset in interface LayoutInfo

Parameters:

position - Index of the item in the adapter

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

approximateRangeSize

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

Description copied from interface: LayoutInfo

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.

Specified by:

approximateRangeSize in interface LayoutInfo

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

public int getChildWidthSpec(int widthSpec,
                             RenderInfo renderInfo)

Specified by:

getChildWidthSpec in interface LayoutInfo

Parameters:

widthSpec - the widthSpec used to measure the parent RecyclerSpec.

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

Returns:

widthSpec of a child that is of span size 1

getChildHeightSpec

public int getChildHeightSpec(int heightSpec,
                              RenderInfo renderInfo)

Specified by:

getChildHeightSpec in interface LayoutInfo

Parameters:

heightSpec - the heightSpec used to measure the parent RecyclerSpec.

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

Returns:

heightSpec of a child that is of span size 1

createViewportFiller

public com.facebook.litho.widget.StaggeredGridLayoutInfo.ViewportFiller createViewportFiller(int measuredWidth,
                                                                                             int measuredHeight)

Specified by:

createViewportFiller in interface LayoutInfo

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.

findFirstVisibleItemPosition

public int findFirstVisibleItemPosition()

Specified by:

findFirstVisibleItemPosition in interface ViewportInfo

Returns:

the adapter position of the first visible view.

findLastVisibleItemPosition

public int findLastVisibleItemPosition()

Specified by:

findLastVisibleItemPosition in interface ViewportInfo

Returns:

the adapter position of the last visible view.

findFirstFullyVisibleItemPosition

public int findFirstFullyVisibleItemPosition()

Specified by:

findFirstFullyVisibleItemPosition in interface ViewportInfo

Returns:

the adapter position of the first fully visible view.

findLastFullyVisibleItemPosition

public int findLastFullyVisibleItemPosition()

Specified by:

findLastFullyVisibleItemPosition in interface ViewportInfo

Returns:

the adapter position of the last fully visible view.

getItemCount

public int getItemCount()

Specified by:

getItemCount in interface ViewportInfo

Returns:

total number of items in the adapter

computeWrappedHeight

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

Specified by:

computeWrappedHeight in interface LayoutInfo

Parameters:

maxHeight - the max height of the parent RecyclerSpec.

componentTreeHolders - the list of ComponentTreeHolder in this RecyclerBinder.

Returns:

the measured height of this RecyclerBinder.