NestedScrollingChildHelper

Kotlin |Java

open class NestedScrollingChildHelper

kotlin.Any
↳	androidx.core.view.NestedScrollingChildHelper

Helper class for implementing nested scrolling child views compatible with Android platform versions earlier than Android 5.0 Lollipop (API 21).

View subclasses should instantiate a final instance of this class as a field at construction. For each View method that has a matching method signature in this class, delegate the operation to the helper instance in an overridden method implementation. This implements the standard framework policy for nested scrolling.

Views invoking nested scrolling functionality should always do so from the relevant androidx.core.view.ViewCompat, androidx.core.view.ViewGroupCompat or androidx.core.view.ViewParentCompat compatibility shim static methods. This ensures interoperability with nested scrolling views on Android 5.0 Lollipop and newer.

Summary

Public constructors
<init>(@NonNull view: View) Construct a new helper for a given view.

Public methods
open Boolean	dispatchNestedFling(velocityX: Float, velocityY: Float, consumed: Boolean) Dispatch a nested fling operation to the current nested scrolling parent.
open Boolean	dispatchNestedPreFling(velocityX: Float, velocityY: Float) Dispatch a nested pre-fling operation to the current nested scrolling parent.
open Boolean	dispatchNestedPreScroll(dx: Int, dy: Int, @Nullable consumed: IntArray?, @Nullable offsetInWindow: IntArray?) Dispatch one step of a nested pre-scrolling operation to the current nested scrolling parent.
open Boolean	dispatchNestedPreScroll(dx: Int, dy: Int, @Nullable consumed: IntArray?, @Nullable offsetInWindow: IntArray?, type: Int) Dispatch one step of a nested pre-scrolling operation to the current nested scrolling parent.
open Boolean	dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, @Nullable offsetInWindow: IntArray?) Dispatch one step of a nested scrolling operation to the current nested scrolling parent.
open Boolean	dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, @Nullable offsetInWindow: IntArray?, type: Int) Dispatch one step of a nested scrolling operation to the current nested scrolling parent.
open Unit	dispatchNestedScroll(dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, @Nullable offsetInWindow: IntArray?, type: Int, @Nullable consumed: IntArray?) Dispatch one step of a nested scrolling operation to the current nested scrolling parent.
open Boolean	hasNestedScrollingParent() Check if this view has a nested scrolling parent view currently receiving events for a nested scroll in progress with the type of touch.
open Boolean	hasNestedScrollingParent(type: Int) Check if this view has a nested scrolling parent view currently receiving events for a nested scroll in progress with the given type.
open Boolean	isNestedScrollingEnabled() Check if nested scrolling is enabled for this view.
open Unit	onDetachedFromWindow() View subclasses should always call this method on their NestedScrollingChildHelper when detached from a window.
open Unit	onStopNestedScroll(@NonNull child: View) Called when a nested scrolling child stops its current nested scroll operation.
open Unit	setNestedScrollingEnabled(enabled: Boolean) Enable nested scrolling.
open Boolean	startNestedScroll(axes: Int) Start a new nested scroll for this view.
open Boolean	startNestedScroll(axes: Int, type: Int) Start a new nested scroll for this view.
open Unit	stopNestedScroll() Stop a nested scroll in progress.
open Unit	stopNestedScroll(type: Int) Stop a nested scroll in progress.

Public constructors

<init>

NestedScrollingChildHelper(@NonNull view: View)

Construct a new helper for a given view.

Public methods

dispatchNestedFling

open fun dispatchNestedFling(
    velocityX: Float, 
    velocityY: Float, 
    consumed: Boolean
): Boolean

Dispatch a nested fling operation to the current nested scrolling parent.

This is a delegate method. Call it from your View subclass method/androidx.core.view.NestedScrollingChild interface method with the same signature to implement the standard policy.

Return
Boolean	true if the parent consumed the nested fling

dispatchNestedPreFling

open fun dispatchNestedPreFling(
    velocityX: Float, 
    velocityY: Float
): Boolean

Dispatch a nested pre-fling operation to the current nested scrolling parent.

This is a delegate method. Call it from your View subclass method/androidx.core.view.NestedScrollingChild interface method with the same signature to implement the standard policy.

Return
Boolean	true if the parent consumed the nested fling

dispatchNestedPreScroll

open fun dispatchNestedPreScroll(
    dx: Int, 
    dy: Int, 
    @Nullable consumed: IntArray?, 
    @Nullable offsetInWindow: IntArray?
): Boolean

Dispatch one step of a nested pre-scrolling operation to the current nested scrolling parent.

This is a delegate method. Call it from your View subclass method/androidx.core.view.NestedScrollingChild interface method with the same signature to implement the standard policy.

Return
Boolean	true if the parent consumed any of the nested scroll

dispatchNestedPreScroll

open fun dispatchNestedPreScroll(
    dx: Int, 
    dy: Int, 
    @Nullable consumed: IntArray?, 
    @Nullable offsetInWindow: IntArray?, 
    type: Int
): Boolean

Dispatch one step of a nested pre-scrolling operation to the current nested scrolling parent.

This is a delegate method. Call it from your View subclass method/androidx.core.view.NestedScrollingChild2 interface method with the same signature to implement the standard policy.

Return
Boolean	true if the parent consumed any of the nested scroll

dispatchNestedScroll

open fun dispatchNestedScroll(
    dxConsumed: Int, 
    dyConsumed: Int, 
    dxUnconsumed: Int, 
    dyUnconsumed: Int, 
    @Nullable offsetInWindow: IntArray?
): Boolean

Dispatch one step of a nested scrolling operation to the current nested scrolling parent.

This is a delegate method. Call it from your