ViewParentCompat
class ViewParentCompat
kotlin.Any | |
↳ | androidx.core.view.ViewParentCompat |
Helper for accessing features in ViewParent
.
Summary
Public methods |
|
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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 |
requestSendAccessibilityEvent(parent: ViewParent!, child: View!, event: AccessibilityEvent!) Called by a child to request from its parent to send an |
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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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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 | |
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target |
ViewParent!: View that initiated the nested scroll |
type |
ViewParent!: the type of input which cause this scroll event |
requestSendAccessibilityEvent
static funrequestSendAccessibilityEvent(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 | |
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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 | |
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Boolean: True if the event was sent. |