ReactAndroid/com.facebook.react.views.scroll/ReactScrollViewHelper

ReactScrollViewHelper

object ReactScrollViewHelper

Helper class that deals with emitting Scroll Events.

Types

HasFlingAnimator

interface HasFlingAnimator

HasScrollEventThrottle

interface HasScrollEventThrottle

interface HasScrollState

HasSmoothScroll

interface HasSmoothScroll

HasStateWrapper

interface HasStateWrapper

LayoutChangeListener

interface LayoutChangeListener

ReactScrollViewScrollState

class ReactScrollViewScrollState

interface ScrollListener

Properties

const val AUTO: String

const val MOMENTUM_DELAY: Long = 20

OVER_SCROLL_ALWAYS

const val OVER_SCROLL_ALWAYS: String

OVER_SCROLL_NEVER

const val OVER_SCROLL_NEVER: String

SNAP_ALIGNMENT_CENTER

const val SNAP_ALIGNMENT_CENTER: Int = 2

SNAP_ALIGNMENT_DISABLED

const val SNAP_ALIGNMENT_DISABLED: Int = 0

SNAP_ALIGNMENT_END

const val SNAP_ALIGNMENT_END: Int = 3

SNAP_ALIGNMENT_START

const val SNAP_ALIGNMENT_START: Int = 1

Functions

addLayoutChangeListener

fun addLayoutChangeListener(listener: ReactScrollViewHelper.LayoutChangeListener)

addScrollListener

fun addScrollListener(listener: ReactScrollViewHelper.ScrollListener)

Adds a scroll listener.

dispatchMomentumEndOnAnimationEnd

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollEventThrottle?, ViewGroup> dispatchMomentumEndOnAnimationEnd(scrollView: T)

emitLayoutChangeEvent

fun emitLayoutChangeEvent(scrollView: ViewGroup)

emitLayoutEvent

fun emitLayoutEvent(scrollView: ViewGroup)

This is only for Java listeners. onLayout events emitted to JS are handled elsewhere.

emitScrollBeginDragEvent

fun <T : ReactScrollViewHelper.HasScrollEventThrottle?, ViewGroup> emitScrollBeginDragEvent(scrollView: T)

emitScrollEndDragEvent

fun <T : ReactScrollViewHelper.HasScrollEventThrottle?, ViewGroup> emitScrollEndDragEvent(scrollView: T, xVelocity: Float, yVelocity: Float)

emitScrollEvent

fun <T : ReactScrollViewHelper.HasScrollEventThrottle?, ViewGroup> emitScrollEvent(scrollView: T, xVelocity: Float, yVelocity: Float)

Shared by ReactScrollView and ReactHorizontalScrollView.

emitScrollMomentumBeginEvent

fun <T : ReactScrollViewHelper.HasScrollEventThrottle?, ViewGroup> emitScrollMomentumBeginEvent(scrollView: T, xVelocity: Int, yVelocity: Int)

emitScrollMomentumEndEvent

fun <T : ReactScrollViewHelper.HasScrollEventThrottle?, ViewGroup> emitScrollMomentumEndEvent(scrollView: T)

forceUpdateState

fun <T : ReactScrollViewHelper.HasScrollState?, ReactScrollViewHelper.HasStateWrapper?, ViewGroup> forceUpdateState(scrollView: T)

getDefaultScrollAnimationDuration

fun getDefaultScrollAnimationDuration(context: Context?): Int

getNextFlingStartValue

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollState?, ViewGroup> getNextFlingStartValue(scrollView: T, currentValue: Int, postAnimationValue: Int, velocity: Int): Int

Get current position or position after current animation finishes, if any.

parseOverScrollMode

fun parseOverScrollMode(jsOverScrollMode: String?): Int

parseSnapToAlignment

fun parseSnapToAlignment(alignment: String?): Int

predictFinalScrollPosition

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollState?, ViewGroup> predictFinalScrollPosition(scrollView: T, velocityX: Int, velocityY: Int, maximumOffsetX: Int, maximumOffsetY: Int): Point

registerFlingAnimator

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollState?, ReactScrollViewHelper.HasStateWrapper?, ViewGroup> registerFlingAnimator(scrollView: T)

removeLayoutChangeListener

fun removeLayoutChangeListener(listener: ReactScrollViewHelper.LayoutChangeListener)

removeScrollListener

fun removeScrollListener(listener: ReactScrollViewHelper.ScrollListener)

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollState?, ReactScrollViewHelper.HasStateWrapper?, ViewGroup> smoothScrollTo(scrollView: T, x: Int, y: Int)

Scroll the given view to the location (x, y), with provided initial velocity. This method works by calculate the "would be" initial velocity with internal friction to move to the point (x, y), then apply that to the animator.

updateFabricScrollState

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollState?, ReactScrollViewHelper.HasStateWrapper?, ViewGroup> updateFabricScrollState(scrollView: T)

fun <T : ReactScrollViewHelper.HasScrollState?, ReactScrollViewHelper.HasStateWrapper?, ViewGroup> updateFabricScrollState(scrollView: T, scrollX: Int, scrollY: Int)

Called on any stabilized onScroll change to propagate content offset value to a Shadow Node.

updateStateOnScrollChanged

fun <T : ReactScrollViewHelper.HasFlingAnimator?, ReactScrollViewHelper.HasScrollEventThrottle?, ReactScrollViewHelper.HasScrollState?, ReactScrollViewHelper.HasStateWrapper?, ViewGroup> updateStateOnScrollChanged(scrollView: T, xVelocity: Float, yVelocity: Float)