NestedScrollingParent3
public
interface
NestedScrollingParent3
implements
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
void
|
onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type, int[] consumed)
React to a nested scroll in progress. |
Inherited methods | |
---|---|
Public methods
onNestedScroll
public abstract void onNestedScroll (View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type, int[] consumed)
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
NestedScrollingParent2.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 |
int : Horizontal scroll distance in pixels already consumed by target |
dyConsumed |
int : Vertical scroll distance in pixels already consumed by target |
dxUnconsumed |
int : Horizontal scroll distance in pixels not consumed by target |
dyUnconsumed |
int : Vertical scroll distance in pixels not consumed by target |
type |
int : the type of input which cause this scroll event |
consumed |
int : 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 |