Summary: Ctors | Methods | Protected Methods | Inherited Methods

PagerSnapHelper

Kotlin |Java

public class PagerSnapHelper
extends SnapHelper

java.lang.Object
↳	androidx.recyclerview.widget.RecyclerView.OnFlingListener
	↳	androidx.recyclerview.widget.SnapHelper
		↳	androidx.recyclerview.widget.PagerSnapHelper

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

PagerSnapHelper can help achieve a similar behavior to ViewPager. Set both RecyclerView and the items of the RecyclerView.Adapter to have ViewGroup.LayoutParams.MATCH_PARENT height and width and then attach PagerSnapHelper to the RecyclerView using SnapHelper.attachToRecyclerView(RecyclerView).

Summary

Public constructors
`PagerSnapHelper()`

Public methods
`int[]`	`calculateDistanceToFinalSnap(RecyclerView.LayoutManager layoutManager, View targetView)` Override this method to snap to a particular point within the target view or the container view on any axis.
`View`	`findSnapView(RecyclerView.LayoutManager layoutManager)` Override this method to provide a particular target view for snapping.
`int`	`findTargetSnapPosition(RecyclerView.LayoutManager layoutManager, int velocityX, int velocityY)` Override to provide a particular adapter target position for snapping.

Protected methods
`RecyclerView.SmoothScroller`	`createScroller(RecyclerView.LayoutManager layoutManager)` Creates a scroller to be used in the snapping implementation.

Inherited methods

From class


        
          androidx.recyclerview.widget.SnapHelper

`void`	`attachToRecyclerView(RecyclerView recyclerView)` Attaches the `SnapHelper` to the provided RecyclerView, by calling `RecyclerView.setOnFlingListener(RecyclerView.OnFlingListener)`.
`abstract int[]`	`calculateDistanceToFinalSnap(RecyclerView.LayoutManager layoutManager, View targetView)` Override this method to snap to a particular point within the target view or the container view on any axis.
`int[]`	`calculateScrollDistance(int velocityX, int velocityY)` Calculated the estimated scroll distance in each direction given velocities on both axes.
`RecyclerView.SmoothScroller`	`createScroller(RecyclerView.LayoutManager layoutManager)` Creates a scroller to be used in the snapping implementation.
`LinearSmoothScroller`	`createSnapScroller(RecyclerView.LayoutManager layoutManager)` This method is deprecated. use `createScroller(RecyclerView.LayoutManager)` instead.
`abstract View`	`findSnapView(RecyclerView.LayoutManager layoutManager)` Override this method to provide a particular target view for snapping.
`abstract int`	`findTargetSnapPosition(RecyclerView.LayoutManager layoutManager, int velocityX, int velocityY)` Override to provide a particular adapter target position for snapping.
`boolean`	`onFling(int velocityX, int velocityY)` Override this to handle a fling given the velocities in both x and y directions.

From class


        
          androidx.recyclerview.widget.RecyclerView.OnFlingListener


        abstract
        
        
        
        
        boolean


      onFling(int velocityX, int velocityY)

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

From class


        
          java.lang.Object

`Object`	`clone()`
`boolean`	`equals(Object arg0)`
`void`	`finalize()`
`final Class<?>`	`getClass()`
`int`	`hashCode()`
`final void`	`notify()`
`final void`	`notifyAll()`
`String`	`toString()`
`final void`	`wait(long arg0, int arg1)`
`final void`	`wait(long arg0)`
`final void`	`wait()`

Public constructors

PagerSnapHelper

public PagerSnapHelper ()

Public methods

public int[] calculateDistanceToFinalSnap (RecyclerView.LayoutManager layoutManager, 
                View targetView)

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
`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.

public View findSnapView (RecyclerView.LayoutManager layoutManager)

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

public int findTargetSnapPosition (RecyclerView.LayoutManager layoutManager, 
                int velocityX, 
                int velocityY)

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 `RecyclerView.NO_POSITION` if no snapping should happen

Protected methods

protected RecyclerView.SmoothScroller createScroller (RecyclerView.LayoutManager layoutManager)

Creates a scroller to be used in the snapping implementation.

Parameters
`layoutManager`	`RecyclerView.LayoutManager`: The `RecyclerView.LayoutManager` associated with the attached `RecyclerView`.

Returns
`RecyclerView.SmoothScroller`	a `RecyclerView.SmoothScroller` which will handle the scrolling.