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SnapHelper

abstract class SnapHelper : RecyclerView.OnFlingListener
kotlin.Any
   ↳ androidx.recyclerview.widget.RecyclerView.OnFlingListener
   ↳ androidx.recyclerview.widget.SnapHelper

Class intended to support snapping for a RecyclerView.

SnapHelper tries to handle fling as well but for this to work properly, the RecyclerView.LayoutManager must implement the RecyclerView.SmoothScroller.ScrollVectorProvider interface or you should override onFling(int, int) and handle fling manually.

Summary

Public constructors

Class intended to support snapping for a RecyclerView.

Public methods
open Unit
attachToRecyclerView(@Nullable recyclerView: RecyclerView?)

Attaches the SnapHelper to the provided RecyclerView, by calling RecyclerView#setOnFlingListener(RecyclerView.OnFlingListener).

abstract IntArray?
calculateDistanceToFinalSnap(@NonNull layoutManager: RecyclerView.LayoutManager, @NonNull targetView: View)

Override this method to snap to a particular point within the target view or the container view on any axis.

open IntArray!
calculateScrollDistance(velocityX: Int, velocityY: Int)

Calculated the estimated scroll distance in each direction given velocities on both axes.

abstract View?

Override this method to provide a particular target view for snapping.

abstract Int
findTargetSnapPosition(layoutManager: RecyclerView.LayoutManager!, velocityX: Int, velocityY: Int)

Override to provide a particular adapter target position for snapping.

open Boolean
onFling(velocityX: Int, velocityY: Int)

Protected methods
open RecyclerView.SmoothScroller?
createScroller(@NonNull layoutManager: RecyclerView.LayoutManager)

Creates a scroller to be used in the snapping implementation.

open LinearSmoothScroller?

Creates a scroller to be used in the snapping implementation.

Public constructors

<init>

SnapHelper()

Class intended to support snapping for a RecyclerView.

SnapHelper tries to handle fling as well but for this to work properly, the RecyclerView.LayoutManager must implement the RecyclerView.SmoothScroller.ScrollVectorProvider interface or you should override onFling(int, int) and handle fling manually.

Public methods

attachToRecyclerView

open fun attachToRecyclerView(@Nullable recyclerView: RecyclerView?): Unit

Attaches the SnapHelper to the provided RecyclerView, by calling RecyclerView#setOnFlingListener(RecyclerView.OnFlingListener). You can call this method with null to detach it from the current RecyclerView.

Parameters
recyclerView RecyclerView?: The RecyclerView instance to which you want to add this helper or null if you want to remove SnapHelper from the current RecyclerView.
Exceptions
IllegalArgumentException if there is already a RecyclerView.OnFlingListener attached to the provided RecyclerView.

calculateDistanceToFinalSnap

@Nullable abstract fun calculateDistanceToFinalSnap(
    @NonNull layoutManager: RecyclerView.LayoutManager,
    @NonNull targetView: View
): IntArray?

Override this method to snap to a particular point within the target view or the container view on any axis.

This method is called when the SnapHelper has intercepted a fling and it needs to know the exact distance required to scroll by in order to snap to the target view.

Parameters
layoutManager RecyclerView.LayoutManager: the RecyclerView.LayoutManager associated with the attached RecyclerView
targetView View: the target view that is chosen as the view to snap
Return
IntArray? the output coordinates the put the result into. out[0] is the distance on horizontal axis and out[1] is the distance on vertical axis.

calculateScrollDistance

open fun calculateScrollDistance(
    velocityX: Int,
    velocityY: