NestedScrollingParent3

interface NestedScrollingParent3 : NestedScrollingParent2
androidx.core.view.NestedScrollingParent3

This interface should be implemented by ViewGroup subclasses that wish to support scrolling operations delegated by a nested child view.

Classes implementing this interface should create a final instance of a NestedScrollingParentHelper as a field and delegate any View or ViewGroup methods to the NestedScrollingParentHelper methods of the same signature.

Views invoking nested scrolling functionality should always do so from the relevant ViewCompat, ViewGroupCompat or ViewParentCompat compatibility shim static methods. This ensures interoperability with nested scrolling views on all versions of Android.

Summary

Public methods

abstract Unit
onNestedScroll(@NonNull target: View, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int, @NonNull consumed: IntArray)

React to a nested scroll in progress.

Inherited functions

Public methods

onNestedScroll

abstract fun onNestedScroll(@NonNull target: View, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int, @NonNull consumed: IntArray): Unit

React to a nested scroll in progress.

This method will be called when the ViewParent's current nested scrolling child view dispatches a nested scroll event. To receive calls to this method the ViewParent must have previously returned true for a call to onStartNestedScroll(View, View, int, int).

Both the consumed and unconsumed portions of the scroll distance are reported to the ViewParent. An implementation may choose to use the consumed portion to match or chase scroll position of multiple child elements, for example. The unconsumed portion may be used to allow continuous dragging of multiple scrolling or draggable elements, such as scrolling a list within a vertical drawer where the drawer begins dragging once the edge of inner scrolling content is reached.

This method is called when a nested scrolling child invokes NestedScrollingChild3#dispatchNestedScroll(int, int, int, int, int[], int, int[])} or one of methods it overloads.

An implementation must report how many pixels of the the x and y scroll distances were consumed by this nested scrolling parent by adding the consumed distances to the consumed parameter. If this View also implements NestedScrollingChild3, consumed should also be passed up to it's nested scrolling parent so that the parent may also add any scroll distance it consumes. Index 0 corresponds to dx and index 1 corresponds to dy.

Parameters
target View: The descendant view controlling the nested scroll
dxConsumed View: Horizontal scroll distance in pixels already consumed by target
dyConsumed View: Vertical scroll distance in pixels already consumed by target
dxUnconsumed View: Horizontal scroll distance in pixels not consumed by target
dyUnconsumed View: Vertical scroll distance in pixels not consumed by target
type View: the type of input which cause this scroll event
consumed View: Output. Upon this method returning, will contain the scroll distances consumed by this nested scrolling parent and the scroll distances consumed by any other parent up the view hierarchy