LinearSnapHelper

class LinearSnapHelper : SnapHelper

kotlin.Any
   ↳ androidx.recyclerview.widget.RecyclerView.OnFlingListener
     ↳ androidx.recyclerview.widget.SnapHelper
       ↳ androidx.recyclerview.widget.LinearSnapHelper

Implementation of the SnapHelper supporting snapping in either vertical or horizontal orientation.

The implementation will snap the center of the target child view to the center of the attached RecyclerView. If you intend to change this behavior then override calculateDistanceToFinalSnap.

Summary

Public constructors

Public functions
IntArray<Int>!
calculateDistanceToFinalSnap(
    layoutManager: RecyclerView.LayoutManager,
    targetView: View
)

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

Override this method to provide a particular target view for snapping.
Int
findTargetSnapPosition(
    layoutManager: RecyclerView.LayoutManager!,
    velocityX: Int,
    velocityY: Int
)

Override to provide a particular adapter target position for snapping.

Inherited functions
From androidx.recyclerview.widget.SnapHelper
Unit

Attaches the SnapHelper to the provided RecyclerView, by calling setOnFlingListener.
IntArray<Int>!
calculateScrollDistance(velocityX: Int, velocityY: Int)

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

Creates a scroller to be used in the snapping implementation.
LinearSmoothScroller?

This function is deprecated.

use createScroller instead.
Boolean
onFling(velocityX: Int, velocityY: Int)

Override this to handle a fling given the velocities in both x and y directions.

Public constructors

LinearSnapHelper

Added in 1.0.0
LinearSnapHelper()

Public functions

calculateDistanceToFinalSnap

Added in 1.4.0-rc01
fun calculateDistanceToFinalSnap(
    layoutManager: RecyclerView.LayoutManager,
    targetView: View
): IntArray<Int>!

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
Returns
IntArray<Int>!

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.

findSnapView

Added in 1.4.0-rc01
fun findSnapView(layoutManager: RecyclerView.LayoutManager!): View!

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

This method is called when the SnapHelper is ready to start snapping and requires a target view to snap to. It will be explicitly called when the scroll state becomes idle after a scroll. It will also be called when the SnapHelper is preparing to snap after a fling and requires a reference view from the current set of child views.

If this method returns null, SnapHelper will not snap to any view.

Parameters
layoutManager: RecyclerView.LayoutManager!

the RecyclerView.LayoutManager associated with the attached RecyclerView
Returns
View!

the target view to which to snap on fling or end of scroll

findTargetSnapPosition

Added in 1.4.0-rc01
fun findTargetSnapPosition(
    layoutManager: RecyclerView.LayoutManager!,
    velocityX: Int,
    velocityY: Int
): Int

Override to provide a particular adapter target position for snapping.

Parameters
layoutManager: RecyclerView.LayoutManager!

the RecyclerView.LayoutManager associated with the attached RecyclerView
velocityX: Int

fling velocity on the horizontal axis
velocityY: Int

fling velocity on the vertical axis
Returns
Int

the target adapter position to you want to snap or NO_POSITION if no snapping should happen