ScrollVectorProvider

Kotlin |Java

interface ScrollVectorProvider

androidx.recyclerview.widget.RecyclerView.SmoothScroller.ScrollVectorProvider

Known Direct Subclasses

LinearLayoutManager, StaggeredGridLayoutManager

LinearLayoutManager	A `RecyclerView.LayoutManager` implementation which provides similar functionality to `android.widget.ListView`.
StaggeredGridLayoutManager	A LayoutManager that lays out children in a staggered grid formation.

Known Indirect Subclasses

GridLayoutManager, WearableLinearLayoutManager

GridLayoutManager	A `RecyclerView.LayoutManager` implementations that lays out items in a grid.
WearableLinearLayoutManager	This wear-specific implementation of `LinearLayoutManager` provides basic offsetting logic for updating child layout.

An interface which is optionally implemented by custom RecyclerView.LayoutManager to provide a hint to a SmoothScroller about the location of the target position.

Summary

Public methods
abstract PointF?	`computeScrollVectorForPosition(targetPosition: Int)` Should calculate the vector that points to the direction where the target position can be found.

Public methods

computeScrollVectorForPosition

@Nullable abstract fun computeScrollVectorForPosition(targetPosition: Int): PointF?

Should calculate the vector that points to the direction where the target position can be found.

This method is used by the LinearSmoothScroller to initiate a scroll towards the target position.

The magnitude of the vector is not important. It is always normalized before being used by the LinearSmoothScroller.

LayoutManager should not check whether the position exists in the adapter or not.

Parameters
`targetPosition`	Int: the target position to which the returned vector should point

Return
`PointF?`	the scroll vector for a given position.