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ViewParentCompat

class ViewParentCompat
kotlin.Any
   ↳ androidx.core.view.ViewParentCompat

Helper for accessing features in ViewParent.

Summary

Public methods

static Unit
notifySubtreeAccessibilityStateChanged(parent: ViewParent!, child: View!, source: View!, changeType: Int)

Notifies a view parent that the accessibility state of one of its descendants has changed and that the structure of the subtree is different.

static Boolean
onNestedFling(parent: ViewParent!, target: View!, velocityX: Float, velocityY: Float, consumed: Boolean)

Request a fling from a nested scroll.

static Boolean
onNestedPreFling(parent: ViewParent!, target: View!, velocityX: Float, velocityY: Float)

React to a nested fling before the target view consumes it.

static Unit
onNestedPreScroll(parent: ViewParent!, target: View!, dx: Int, dy: Int, consumed: IntArray!)

React to a nested scroll in progress before the target view consumes a portion of the scroll.

static Unit
onNestedPreScroll(parent: ViewParent!, target: View!, dx: Int, dy: Int, consumed: IntArray!, type: Int)

React to a nested scroll in progress before the target view consumes a portion of the scroll.

static Unit
onNestedScroll(parent: ViewParent!, target: View!, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int)

React to a nested scroll in progress.

static Unit
onNestedScroll(parent: ViewParent!, target: View!, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int)

React to a nested scroll in progress.

static Unit
onNestedScroll(parent: ViewParent!, target: View!, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int, @NonNull consumed: IntArray)

React to a nested scroll in progress.

static Unit
onNestedScrollAccepted(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int)

React to the successful claiming of a nested scroll operation.

static Unit
onNestedScrollAccepted(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int, type: Int)

React to the successful claiming of a nested scroll operation.

static Boolean
onStartNestedScroll(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int)

React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate.

static Boolean
onStartNestedScroll(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int, type: Int)

React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate.

static Unit
onStopNestedScroll(parent: ViewParent!, target: View!)

React to a nested scroll operation ending.

static Unit
onStopNestedScroll(parent: ViewParent!, target: View!, type: Int)

React to a nested scroll operation ending.

static Boolean

Called by a child to request from its parent to send an AccessibilityEvent.

Public methods

notifySubtreeAccessibilityStateChanged

static fun notifySubtreeAccessibilityStateChanged(parent: ViewParent!, child: View!, source: View!, changeType: Int): Unit

Notifies a view parent that the accessibility state of one of its descendants has changed and that the structure of the subtree is different.

Parameters
child ViewParent!: The direct child whose subtree has changed.
source ViewParent!: The descendant view that changed.
changeType ViewParent!: A bit mask of the types of changes that occurred. One or more of:

onNestedFling

static fun onNestedFling(parent: ViewParent!, target: View!, velocityX: Float, velocityY: Float, consumed: Boolean): Boolean

Request a fling from a nested scroll.

This method signifies that a nested scrolling child has detected suitable conditions for a fling. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

If a nested scrolling child view would normally fling but it is at the edge of its own content, it can use this method to delegate the fling to its nested scrolling parent instead. The parent may optionally consume the fling or observe a child fling.

Parameters
target ViewParent!: View that initiated the nested scroll
velocityX ViewParent!: Horizontal velocity in pixels per second
velocityY ViewParent!: Vertical velocity in pixels per second
consumed ViewParent!: true if the child consumed the fling, false otherwise
Return
Boolean: true if this parent consumed or otherwise reacted to the fling

onNestedPreFling

static fun onNestedPreFling(parent: ViewParent!, target: View!, velocityX: Float, velocityY: Float): Boolean

React to a nested fling before the target view consumes it.

This method siginfies that a nested scrolling child has detected a fling with the given velocity along each axis. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

If a nested scrolling parent is consuming motion as part of a pre-scroll, it may be appropriate for it to also consume the pre-fling to complete that same motion. By returning true from this method, the parent indicates that the child should not fling its own internal content as well.

Parameters
target ViewParent!: View that initiated the nested scroll
velocityX ViewParent!: Horizontal velocity in pixels per second
velocityY ViewParent!: Vertical velocity in pixels per second
Return
Boolean: true if this parent consumed the fling ahead of the target view

onNestedPreScroll

static fun onNestedPreScroll(parent: ViewParent!, target: View!, dx: Int, dy: Int, consumed: IntArray!): Unit

React to a nested scroll in progress before the target view consumes a portion of the scroll.

This version of the method just calls onNestedPreScroll(ViewParent, View, int, int, int[], int) using the touch input type.

Parameters
target ViewParent!: View that initiated the nested scroll
dx ViewParent!: Horizontal scroll distance in pixels
dy ViewParent!: Vertical scroll distance in pixels
consumed ViewParent!: Output. The horizontal and vertical scroll distance consumed by this parent

onNestedPreScroll

static fun onNestedPreScroll(parent: ViewParent!, target: View!, dx: Int, dy: Int, consumed: IntArray!, type: Int): Unit

React to a nested scroll in progress before the target view consumes a portion of the scroll.

When working with nested scrolling often the parent view may want an opportunity to consume the scroll before the nested scrolling child does. An example of this is a drawer that contains a scrollable list. The user will want to be able to scroll the list fully into view before the list itself begins scrolling.

onNestedPreScroll is called when a nested scrolling child invokes ViewCompat#dispatchNestedPreScroll(View, int, int, int[], int[]). The implementation should report how any pixels of the scroll reported by dx, dy were consumed in the consumed array. Index 0 corresponds to dx and index 1 corresponds to dy. This parameter will never be null. Initial values for consumed[0] and consumed[1] will always be 0.

Parameters
target ViewParent!: View that initiated the nested scroll
dx ViewParent!: Horizontal scroll distance in pixels
dy ViewParent!: Vertical scroll distance in pixels
consumed ViewParent!: Output. The horizontal and vertical scroll distance consumed by this parent
type ViewParent!: the type of input which cause this scroll event

onNestedScroll

static fun onNestedScroll(parent: ViewParent!, target: View!, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int): Unit

React to a nested scroll in progress.

This version of the method just calls onNestedScroll(ViewParent, View, int, int, int, int, int) using the touch input type.

Parameters
target ViewParent!: The descendent view controlling the nested scroll
dxConsumed ViewParent!: Horizontal scroll distance in pixels already consumed by target
dyConsumed ViewParent!: Vertical scroll distance in pixels already consumed by target
dxUnconsumed ViewParent!: Horizontal scroll distance in pixels not consumed by target
dyUnconsumed ViewParent!: Vertical scroll distance in pixels not consumed by target

onNestedScroll

static fun onNestedScroll(parent: ViewParent!, target: View!, dxConsumed: Int, dyConsumed: Int, dxUnconsumed: Int, dyUnconsumed: Int, type: Int): 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(ViewParent, 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.

Parameters
target ViewParent!: The descendent view controlling the nested scroll
dxConsumed ViewParent!: Horizontal scroll distance in pixels already consumed by target
dyConsumed ViewParent!: Vertical scroll distance in pixels already consumed by target
dxUnconsumed ViewParent!: Horizontal scroll distance in pixels not consumed by target
dyUnconsumed ViewParent!: Vertical scroll distance in pixels not consumed by target
type ViewParent!: the type of input which cause this scroll event

onNestedScroll

static fun onNestedScroll(parent: ViewParent!, 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(ViewParent, 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.

Parameters
target ViewParent!: The descendent view controlling the nested scroll
dxConsumed ViewParent!: Horizontal scroll distance in pixels already consumed by target
dyConsumed ViewParent!: Vertical scroll distance in pixels already consumed by target
dxUnconsumed ViewParent!: Horizontal scroll distance in pixels not consumed by target
dyUnconsumed ViewParent!: Vertical scroll distance in pixels not consumed by target
type ViewParent!: the type of input which cause this scroll event
consumed ViewParent!: Output. If not null, 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.

onNestedScrollAccepted

static fun onNestedScrollAccepted(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int): Unit

React to the successful claiming of a nested scroll operation.

This version of the method just calls onNestedScrollAccepted(ViewParent, View, View, int, int) using the touch input type.

Parameters
child ViewParent!: Direct child of this ViewParent containing target
target ViewParent!: View that initiated the nested scroll
nestedScrollAxes ViewParent!: Flags consisting of ViewCompat#SCROLL_AXIS_HORIZONTAL, ViewCompat#SCROLL_AXIS_VERTICAL or both

onNestedScrollAccepted

static fun onNestedScrollAccepted(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int, type: Int): Unit

React to the successful claiming of a nested scroll operation.

This method will be called after onStartNestedScroll returns true. It offers an opportunity for the view and its superclasses to perform initial configuration for the nested scroll. Implementations of this method should always call their superclass's implementation of this method if one is present.

Parameters
child ViewParent!: Direct child of this ViewParent containing target
target ViewParent!: View that initiated the nested scroll
nestedScrollAxes ViewParent!: Flags consisting of ViewCompat#SCROLL_AXIS_HORIZONTAL, ViewCompat#SCROLL_AXIS_VERTICAL or both
type ViewParent!: the type of input which cause this scroll event

onStartNestedScroll

static fun onStartNestedScroll(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int): Boolean

React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate.

This version of the method just calls onStartNestedScroll(ViewParent, View, View, int, int) using the touch input type.

Parameters
child ViewParent!: Direct child of this ViewParent containing target
target ViewParent!: View that initiated the nested scroll
nestedScrollAxes ViewParent!: Flags consisting of ViewCompat#SCROLL_AXIS_HORIZONTAL, ViewCompat#SCROLL_AXIS_VERTICAL or both
Return
Boolean: true if this ViewParent accepts the nested scroll operation

onStartNestedScroll

static fun onStartNestedScroll(parent: ViewParent!, child: View!, target: View!, nestedScrollAxes: Int, type: Int): Boolean

React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate.

This method will be called in response to a descendant view invoking ViewCompat#startNestedScroll(View, int). Each parent up the view hierarchy will be given an opportunity to respond and claim the nested scrolling operation by returning true.

This method may be overridden by ViewParent implementations to indicate when the view is willing to support a nested scrolling operation that is about to begin. If it returns true, this ViewParent will become the target view's nested scrolling parent for the duration of the scroll operation in progress. When the nested scroll is finished this ViewParent will receive a call to onStopNestedScroll(ViewParent, View, int).

Parameters
child ViewParent!: Direct child of this ViewParent containing target
target ViewParent!: View that initiated the nested scroll
nestedScrollAxes ViewParent!: Flags consisting of ViewCompat#SCROLL_AXIS_HORIZONTAL, ViewCompat#SCROLL_AXIS_VERTICAL or both
type ViewParent!: the type of input which cause this scroll event
Return
Boolean: true if this ViewParent accepts the nested scroll operation

onStopNestedScroll

static fun onStopNestedScroll(parent: ViewParent!, target: View!): Unit

React to a nested scroll operation ending.

This version of the method just calls onStopNestedScroll(ViewParent, View) using the touch input type.

Parameters
target ViewParent!: View that initiated the nested scroll

onStopNestedScroll

static fun onStopNestedScroll(parent: ViewParent!, target: View!, type: Int): Unit

React to a nested scroll operation ending.

Perform cleanup after a nested scrolling operation. This method will be called when a nested scroll stops, for example when a nested touch scroll ends with a MotionEvent#ACTION_UP or MotionEvent#ACTION_CANCEL event. Implementations of this method should always call their superclass's implementation of this method if one is present.

Parameters
target ViewParent!: View that initiated the nested scroll
type ViewParent!: the type of input which cause this scroll event

requestSendAccessibilityEvent

static fun requestSendAccessibilityEvent(parent: ViewParent!, child: View!, event: AccessibilityEvent!): Boolean

Deprecated: Use ViewParent#requestSendAccessibilityEvent(View, AccessibilityEvent) directly.

Called by a child to request from its parent to send an AccessibilityEvent. The child has already populated a record for itself in the event and is delegating to its parent to send the event. The parent can optionally add a record for itself.

Note: An accessibility event is fired by an individual view which populates the event with a record for its state and requests from its parent to perform the sending. The parent can optionally add a record for itself before dispatching the request to its parent. A parent can also choose not to respect the request for sending the event. The accessibility event is sent by the topmost view in the view tree.

Parameters
parent ViewParent!: The parent whose method to invoke.
child ViewParent!: The child which requests sending the event.
event ViewParent!: The event to be sent.
Return
Boolean: True if the event was sent.