LinearSnapHelper

Artifact: androidx.recyclerview:recyclerview

Added in 1.0.0

Kotlin |Java

public class LinearSnapHelper extends SnapHelper

java.lang.Object
↳	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
`LinearSnapHelper()`

Public methods
`int[]`	`calculateDistanceToFinalSnap( @NonNull RecyclerView.LayoutManager layoutManager, @NonNull 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.

Inherited methods

From androidx.recyclerview.widget.SnapHelper

`void`	`attachToRecyclerView(@Nullable RecyclerView recyclerView)` Attaches the `SnapHelper` to the provided RecyclerView, by calling `setOnFlingListener`.
`int[]`	`calculateScrollDistance(int velocityX, int velocityY)` Calculated the estimated scroll distance in each direction given velocities on both axes.
`@Nullable RecyclerView.SmoothScroller`	`createScroller(@NonNull RecyclerView.LayoutManager layoutManager)` Creates a scroller to be used in the snapping implementation.
`@Nullable LinearSmoothScroller`	`createSnapScroller(@NonNull RecyclerView.LayoutManager layoutManager)` This method is deprecated. use `createScroller` instead.
`boolean`	`onFling(int velocityX, int velocityY)` Override this to handle a fling given the velocities in both x and y directions.

Public constructors

LinearSnapHelper

Added in 1.0.0

public LinearSnapHelper()

Public methods

Added in 1.4.0

public int[] calculateDistanceToFinalSnap(
    @NonNull RecyclerView.LayoutManager layoutManager,
    @NonNull 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
`@NonNull RecyclerView.LayoutManager layoutManager`	the `RecyclerView.LayoutManager` associated with the attached `RecyclerView`
`@NonNull View targetView`	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.

Added in 1.4.0

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
`RecyclerView.LayoutManager layoutManager`	the `RecyclerView.LayoutManager` associated with the attached `RecyclerView`

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

Added in 1.4.0

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

Override to provide a particular adapter target position for snapping.

Parameters
`RecyclerView.LayoutManager layoutManager`	the `RecyclerView.LayoutManager` associated with the attached `RecyclerView`
`int velocityX`	fling velocity on the horizontal axis
`int velocityY`	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