com.facebook.litho.widget

Class VerticalScroll

java.lang.Object

com.facebook.litho.Component

com.facebook.litho.SpecGeneratedComponent

com.facebook.litho.widget.VerticalScroll

All Implemented Interfaces:

Equivalence<Component>, EventDispatcher, EventTriggerTarget, HasEventDispatcher, HasEventTrigger, ContentAllocator, java.lang.Cloneable

public final class VerticalScroll
extends SpecGeneratedComponent

Component that wraps another component, allowing it to be vertically scrollable. It's analogous to android.widget.ScrollView. TreeProps will only be set during @OnCreateInitialState once, so updating TreeProps on the parent will not reflect on the VerticalScroll.

See also: HorizontalScroll for horizontal scrollability.

See Also:

com.facebook.litho.widget.VerticalScrollSpec

Required Props

childComponent

Type:

com.facebook.litho.Component

Optional Props

eventsController

Type:

com.facebook.litho.widget.VerticalScrollEventsController

fadingEdgeLength

size of the faded edge used to indicate that more content is available

Type:

int

fillViewport

Type:

boolean

incrementalMountEnabled

Type:

boolean

initialScrollOffsetPixels

Type:

int

nestedScrollingEnabled

Type:

boolean

onInterceptTouchListener

NOT THE SAME AS LITHO'S interceptTouchHandler COMMON PROP. this is a listener that handles the underlying ScrollView's onInterceptTouchEvent first, whereas the Litho prop wraps the component into another view and intercepts there.

Type:

com.facebook.litho.widget.LithoScrollView.OnInterceptTouchListener

onScrollChangeListener

Type:

androidx.core.widget.NestedScrollView.OnScrollChangeListener

overScrollMode

Type:

int

scrollStateListener

Type:

com.facebook.litho.widget.ScrollStateListener

scrollbarEnabled

whether the vertical scrollbar should be drawn

Type:

boolean

scrollbarFadingEnabled

whether the scrollbar should fade out when the view is not scrolling @props initialScrollOffsetPixels initial vertical scroll offset, in pixels @props verticalFadingEdgeEnabled whether the vertical edges should be faded when scrolled

Type:

boolean

verticalFadingEdgeEnabled

Type:

boolean

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	VerticalScroll.Builder

Nested classes/interfaces inherited from class com.facebook.litho.SpecGeneratedComponent

SpecGeneratedComponent.TransitionContainer

Nested classes/interfaces inherited from class com.facebook.litho.Component

Component.ContainerBuilder<T extends Component.ContainerBuilder<T>>, Component.MountType, Component.RenderData

Method Summary

Modifier and Type	Method and Description
protected boolean	canMeasure() Whether this Component is able to measure itself according to specific size constraints.
boolean	canPreallocate() This API informs the framework to fill the content pool for this Mountable ahead of time.
protected void	copyInterStageImpl(InterStagePropsContainer copyIntoInterStagePropsContainer, InterStagePropsContainer copyFromInterStagePropsContainer)
static VerticalScroll.Builder	create(ComponentContext context)
static VerticalScroll.Builder	create(ComponentContext context, int defStyleAttr, int defStyleRes)
protected void	createInitialState(ComponentContext context)
protected com.facebook.litho.widget.VerticalScroll.VerticalScrollInterStagePropsContainer	createInterStagePropsContainer()
protected com.facebook.litho.widget.VerticalScroll.VerticalScrollStateContainer	createStateContainer()
Component.MountType	getMountType() This indicates the type of the Object that will be returned by com.facebook.litho.Component#mount.
boolean	hasChildLithoViews() Whether this Component mounts views that contain component-based content that can be incrementally mounted e.g.
protected boolean	hasState()
boolean	implementsShouldUpdate()
boolean	isEquivalentProps(Component other, boolean shouldCompareCommonProps) Determine if this component has equivalent props to a given component.
boolean	isPureRender()
VerticalScroll	makeShallowCopy()
protected void	onBoundsDefined(ComponentContext c, ComponentLayout layout, InterStagePropsContainer _2) Called after the layout calculation is finished and the given ComponentLayout has its bounds defined.
protected java.lang.Object	onCreateMountContent(Context context) Create the object that will be mounted in the LithoView.
protected void	onMeasure(ComponentContext c, ComponentLayout layout, int widthSpec, int heightSpec, Size size, InterStagePropsContainer _5)
protected void	onMount(ComponentContext context, java.lang.Object lithoScrollView, InterStagePropsContainer _2) Deploy all UI elements representing the final bounds defined in the given ComponentLayout.
protected void	onUnmount(ComponentContext context, java.lang.Object lithoScrollView, InterStagePropsContainer _2) Unload UI elements associated with this component.
int	poolSize() This API informs the framework about the size of the content pool.
protected boolean	shouldUpdate(Component _prevAbstractImpl, StateContainer _prevStateContainer, Component _nextAbstractImpl, StateContainer _nextStateContainer) Whether the component needs updating.
protected void	transferState(StateContainer _prevStateContainer, StateContainer _nextStateContainer) Call this to transfer the State annotated values between two Component with the same global scope.

Methods inherited from class com.facebook.litho.SpecGeneratedComponent

acceptTriggerEvent, acceptTriggerEventImpl, applyPreviousRenderData, bindDynamicProp, copyPrepareInterStageImpl, createContent, createPoolableContent, createPrepareInterStagePropsContainer, createRecyclingPool, dispatchOnEnteredRange, dispatchOnExitedRange, getExtraAccessibilityNodeAt, getExtraAccessibilityNodesCount, getInterStagePropsContainer, getPoolableContentType, getPrepareInterStagePropsContainer, getSimpleName, getSimpleNameDelegate, getTreePropsForChildren, hasAttachDetachCallback, hasOwnErrorHandler, implementsAccessibility, implementsExtraAccessibilityNodes, isMountSizeDependent, isRecyclingDisabled, needsPreviousRenderData, onAttached, onBind, onCreateLayout, onCreateLayoutWithSizeSpec, onCreateMountContentPool, onDetached, onError, onMeasureBaseline, onPrepare, onUnbind, populateTreeProps, prepare, recordEventTrigger, recordRenderData, render, shouldAlwaysRemeasure, usesLocalStateContainer

Methods inherited from class com.facebook.litho.Component

clone, createMountContent, dispatchErrorEvent, dispatchOnEvent, dispatchOnEventImpl, equals, excludeFromIncrementalMount, getCommonProps, getDynamicProps, getErrorHandler, getEventDispatcher, getEventTrigger, getEventTrigger, getHandle, getTreePropFromParent, getTypeId, hasClickHandlerSet, hashCode, isEqualivalentTreeProps, isEquivalentCommonProps, isEquivalentTo, isEquivalentTo, isLayoutSpecWithSizeSpec, isPureRender, measure, measure, measureMightNotCacheInternalNode, newEventHandler, newEventTrigger, newEventTrigger, onCreateTransition, onLoadStyle, onPopulateAccessibilityNode, onPopulateExtraAccessibilityNode, registerWorkingRange, resolve, retrieveValue, toString, willRender

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

createStateContainer

protected com.facebook.litho.widget.VerticalScroll.VerticalScrollStateContainer createStateContainer()

Overrides:

createStateContainer in class SpecGeneratedComponent

createInterStagePropsContainer

protected com.facebook.litho.widget.VerticalScroll.VerticalScrollInterStagePropsContainer createInterStagePropsContainer()

Overrides:

createInterStagePropsContainer in class SpecGeneratedComponent

isEquivalentProps

public boolean isEquivalentProps(Component other,
                                 boolean shouldCompareCommonProps)

Description copied from class: Component

Determine if this component has equivalent props to a given component. This method does not compare common props.

Overrides:

isEquivalentProps in class Component

Parameters:

other - the component to compare to

Returns:

true if the components have equivalent props

copyInterStageImpl

protected void copyInterStageImpl(InterStagePropsContainer copyIntoInterStagePropsContainer,
                                  InterStagePropsContainer copyFromInterStagePropsContainer)

Overrides:

copyInterStageImpl in class SpecGeneratedComponent

makeShallowCopy

public VerticalScroll makeShallowCopy()

Overrides:

makeShallowCopy in class Component

createInitialState

protected void createInitialState(ComponentContext context)

Overrides:

createInitialState in class SpecGeneratedComponent

onMeasure

protected void onMeasure(ComponentContext c,
                         ComponentLayout layout,
                         int widthSpec,
                         int heightSpec,
                         Size size,
                         InterStagePropsContainer _5)

Overrides:

onMeasure in class SpecGeneratedComponent

canMeasure

protected boolean canMeasure()

Description copied from class: Component

Whether this Component is able to measure itself according to specific size constraints.

Overrides:

canMeasure in class Component

onBoundsDefined

protected void onBoundsDefined(ComponentContext c,
                               ComponentLayout layout,
                               InterStagePropsContainer _2)

Description copied from class: SpecGeneratedComponent

Called after the layout calculation is finished and the given ComponentLayout has its bounds defined. You can use ComponentLayout.getX(), ComponentLayout.getY(), ComponentLayout.getWidth(), and ComponentLayout.getHeight() to get the size and position of the component in the layout tree.

Overrides:

onBoundsDefined in class SpecGeneratedComponent

Parameters:

c - The Context used by this component.

layout - The ComponentLayout with defined position and size.

onCreateMountContent

protected java.lang.Object onCreateMountContent(Context context)

Description copied from class: Component

Create the object that will be mounted in the LithoView.

Overrides:

onCreateMountContent in class Component

Parameters:

context - The Context to be used to create the content.

Returns:

an Object that can be mounted for this component.

onMount

protected void onMount(ComponentContext context,
                       java.lang.Object lithoScrollView,
                       InterStagePropsContainer _2)

Description copied from class: SpecGeneratedComponent

Deploy all UI elements representing the final bounds defined in the given ComponentLayout. Return either a Drawable or a View or null to be mounted.

Overrides:

onMount in class SpecGeneratedComponent

Parameters:

context - The ComponentContext to mount the component into.

onUnmount

protected void onUnmount(ComponentContext context,
                         java.lang.Object lithoScrollView,
                         InterStagePropsContainer _2)

Description copied from class: SpecGeneratedComponent

Unload UI elements associated with this component.

Overrides:

onUnmount in class SpecGeneratedComponent

Parameters:

context - The Context for this mount operation.

lithoScrollView - The Drawable or View mounted by this component.

shouldUpdate

protected boolean shouldUpdate(Component _prevAbstractImpl,
                               StateContainer _prevStateContainer,
                               Component _nextAbstractImpl,
                               StateContainer _nextStateContainer)

Description copied from class: Component

Whether the component needs updating.

For layout components, the framework will verify that none of the children of the component need updating, and that both components have the same number of children. Therefore this method just needs to determine any changes to the top-level component that would cause it to need to be updated (for example, a click handler was added).

For mount specs, the framework does nothing extra and this method alone determines whether the component is updated or not.

Overrides:

shouldUpdate in class Component

Parameters:

_prevAbstractImpl - the previous component to compare against.

_nextAbstractImpl - the component that is now in use.

Returns:

true if the component needs an update, false otherwise.

implementsShouldUpdate

public boolean implementsShouldUpdate()

Overrides:

implementsShouldUpdate in class Component

getMountType

public Component.MountType getMountType()

Description copied from class: Component

This indicates the type of the Object that will be returned by com.facebook.litho.Component#mount.

Overrides:

getMountType in class Component

Returns:

one of Component.MountType

poolSize

public int poolSize()

Description copied from interface: ContentAllocator

This API informs the framework about the size of the content pool. The default is 3.

Experimental. Currently for Litho team internal use only.

Specified by:

poolSize in interface ContentAllocator

Overrides:

poolSize in class SpecGeneratedComponent

canPreallocate

public boolean canPreallocate()

Description copied from interface: ContentAllocator

This API informs the framework to fill the content pool for this Mountable ahead of time. The default value is false, i.e. content is not pre-allocated. Pre-allocation of the content can improve performance in some circumstances where creating the content is expensive.

Specified by:

canPreallocate in interface ContentAllocator

Overrides:

canPreallocate in class SpecGeneratedComponent

Returns:

true if this component can be preallocated.

hasChildLithoViews

public boolean hasChildLithoViews()

Description copied from class: Component

Whether this Component mounts views that contain component-based content that can be incrementally mounted e.g. if the mounted view has a LithoView with incremental mount enabled.

Overrides:

hasChildLithoViews in class Component

isPureRender

public boolean isPureRender()

Overrides:

isPureRender in class Component

hasState

protected boolean hasState()

Overrides:

hasState in class SpecGeneratedComponent

Returns:

true if the Component is using state, false otherwise.

transferState

protected void transferState(StateContainer _prevStateContainer,
                             StateContainer _nextStateContainer)

Description copied from class: Component

Call this to transfer the State annotated values between two Component with the same global scope.

Overrides:

transferState in class Component

create

public static VerticalScroll.Builder create(ComponentContext context)

create

public static VerticalScroll.Builder create(ComponentContext context,
                                            int defStyleAttr,
                                            int defStyleRes)