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CoordinatorLayout.Behavior

public static abstract class CoordinatorLayout.Behavior
extends Object

java.lang.Object
   ↳ android.support.design.widget.CoordinatorLayout.Behavior<V extends android.view.View>
Known Direct Subclasses


Interaction behavior plugin for child views of CoordinatorLayout.

A Behavior implements one or more interactions that a user can take on a child view. These interactions may include drags, swipes, flings, or any other gestures.

Summary

Public constructors

CoordinatorLayout.Behavior()

Default constructor for instantiating Behaviors.

CoordinatorLayout.Behavior(Context context, AttributeSet attrs)

Default constructor for inflating Behaviors from layout.

Public methods

boolean blocksInteractionBelow(CoordinatorLayout parent, V child)

Determine whether interaction with views behind the given child in the child order should be blocked.

boolean getInsetDodgeRect(CoordinatorLayout parent, V child, Rect rect)

Called when a view is set to dodge view insets.

int getScrimColor(CoordinatorLayout parent, V child)

Supply a scrim color that will be painted behind the associated child view.

float getScrimOpacity(CoordinatorLayout parent, V child)

Determine the current opacity of the scrim behind a given child view

A scrim may be used to indicate that the other elements beneath it are not currently interactive or actionable, drawing user focus and attention to the views above the scrim.

static Object getTag(View child)

Get the behavior-specific tag object with the given child view.

boolean layoutDependsOn(CoordinatorLayout parent, V child, View dependency)

Determine whether the supplied child view has another specific sibling view as a layout dependency.

WindowInsetsCompat onApplyWindowInsets(CoordinatorLayout coordinatorLayout, V child, WindowInsetsCompat insets)

Called when the window insets have changed.

void onAttachedToLayoutParams(CoordinatorLayout.LayoutParams params)

Called when the Behavior has been attached to a LayoutParams instance.

boolean onDependentViewChanged(CoordinatorLayout parent, V child, View dependency)

Respond to a change in a child's dependent view

This method is called whenever a dependent view changes in size or position outside of the standard layout flow.

void onDependentViewRemoved(CoordinatorLayout parent, V child, View dependency)

Respond to a child's dependent view being removed.

void onDetachedFromLayoutParams()

Called when the Behavior has been detached from its holding LayoutParams instance.

boolean onInterceptTouchEvent(CoordinatorLayout parent, V child, MotionEvent ev)

Respond to CoordinatorLayout touch events before they are dispatched to child views.

boolean onLayoutChild(CoordinatorLayout parent, V child, int layoutDirection)

Called when the parent CoordinatorLayout is about the lay out the given child view.

boolean onMeasureChild(CoordinatorLayout parent, V child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed)

Called when the parent CoordinatorLayout is about to measure the given child view.

boolean onNestedFling(CoordinatorLayout coordinatorLayout, V child, View target, float velocityX, float velocityY, boolean consumed)

Called when a nested scrolling child is starting a fling or an action that would be a fling.

boolean onNestedPreFling(CoordinatorLayout coordinatorLayout, V child, View target, float velocityX, float velocityY)

Called when a nested scrolling child is about to start a fling.

void onNestedPreScroll(CoordinatorLayout coordinatorLayout, V child, View target, int dx, int dy, int[] consumed)

This method was deprecated in API level 26.0.0. You should now override onNestedPreScroll(CoordinatorLayout, View, View, int, int, int[], int). This method will still continue to be called if the type is TYPE_TOUCH.

void onNestedPreScroll(CoordinatorLayout coordinatorLayout, V child, View target, int dx, int dy, int[] consumed, int type)

Called when a nested scroll in progress is about to update, before the target has consumed any of the scrolled distance.

void onNestedScroll(CoordinatorLayout coordinatorLayout, V child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed)

This method was deprecated in API level 26.0.0. You should now override onNestedScroll(CoordinatorLayout, View, View, int, int, int, int, int). This method will still continue to be called if the type is TYPE_TOUCH.

void onNestedScroll(CoordinatorLayout coordinatorLayout, V child, View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type)

Called when a nested scroll in progress has updated and the target has scrolled or attempted to scroll.

void onNestedScrollAccepted(CoordinatorLayout coordinatorLayout, V child, View directTargetChild, View target, int axes, int type)

Called when a nested scroll has been accepted by the CoordinatorLayout.

void onNestedScrollAccepted(CoordinatorLayout coordinatorLayout, V child, View directTargetChild, View target, int axes)

This method was deprecated in API level 26.0.0. You should now override onNestedScrollAccepted(CoordinatorLayout, View, View, View, int, int). This method will still continue to be called if the type is TYPE_TOUCH.

boolean onRequestChildRectangleOnScreen(CoordinatorLayout coordinatorLayout, V child, Rect rectangle, boolean immediate)

Called when a child of the view associated with this behavior wants a particular rectangle to be positioned onto the screen.

void onRestoreInstanceState(CoordinatorLayout parent, V child, Parcelable state)

Hook allowing a behavior to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState(CoordinatorLayout, V).

Parcelable onSaveInstanceState(CoordinatorLayout parent, V child)

Hook allowing a behavior to generate a representation of its internal state that can later be used to create a new instance with that same state.

boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, V child, View directTargetChild, View target, int axes)

This method was deprecated in API level 26.0.0. You should now override onStartNestedScroll(CoordinatorLayout, View, View, View, int, int). This method will still continue to be called if the type is TYPE_TOUCH.

boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, V child, View directTargetChild, View target, int axes, int type)

Called when a descendant of the CoordinatorLayout attempts to initiate a nested scroll.

void onStopNestedScroll(CoordinatorLayout coordinatorLayout, V child, View target)

This method was deprecated in API level 26.0.0. You should now override onStopNestedScroll(CoordinatorLayout, View, View, int). This method will still continue to be called if the type is TYPE_TOUCH.

void onStopNestedScroll(CoordinatorLayout coordinatorLayout, V child, View target, int type)

Called when a nested scroll has ended.

boolean onTouchEvent(CoordinatorLayout parent, V child, MotionEvent ev)

Respond to CoordinatorLayout touch events after this Behavior has started intercepting them.

static void setTag(View child, Object tag)

Associate a Behavior-specific tag object with the given child view.

Inherited methods

From class java.lang.Object

Public constructors

CoordinatorLayout.Behavior

added in version 22.2.0
CoordinatorLayout.Behavior ()

Default constructor for instantiating Behaviors.

CoordinatorLayout.Behavior

added in version 22.2.0
CoordinatorLayout.Behavior (Context context, 
                AttributeSet attrs)

Default constructor for inflating Behaviors from layout. The Behavior will have the opportunity to parse specially defined layout parameters. These parameters will appear on the child view tag.

Public methods

blocksInteractionBelow

added in version 22.2.0
boolean blocksInteractionBelow (CoordinatorLayout parent, 
                V child)

Determine whether interaction with views behind the given child in the child order should be blocked.

The default implementation returns true if getScrimOpacity(CoordinatorLayout, android.view.View) would return > 0.0f.

Parameters
parent CoordinatorLayout: the parent view of the given child

child V: the child view to test

Returns
boolean true if getScrimOpacity(CoordinatorLayout, android.view.View) would return > 0.0f.

getInsetDodgeRect

added in version 24.2.0
boolean getInsetDodgeRect (CoordinatorLayout parent, 
                V child, 
                Rect rect)

Called when a view is set to dodge view insets.

This method allows a behavior to update the rectangle that should be dodged. The rectangle should be in the parent's coordinate system and within the child's bounds. If not, a IllegalArgumentException is thrown.

Parameters
parent CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

rect Rect: the rect to update with the dodge rectangle

Returns
boolean true the rect was updated, false if we should use the child's bounds

getScrimColor

added in version 22.2.0
int getScrimColor (CoordinatorLayout parent, 
                V child)

Supply a scrim color that will be painted behind the associated child view.

A scrim may be used to indicate that the other elements beneath it are not currently interactive or actionable, drawing user focus and attention to the views above the scrim.

The default implementation returns BLACK.

Parameters
parent CoordinatorLayout: the parent view of the given child

child V: the child view above the scrim

Returns
int the desired scrim color in 0xAARRGGBB format. The default return value is BLACK.

See also:

getScrimOpacity

added in version 22.2.0
float getScrimOpacity (CoordinatorLayout parent, 
                V child)

Determine the current opacity of the scrim behind a given child view

A scrim may be used to indicate that the other elements beneath it are not currently interactive or actionable, drawing user focus and attention to the views above the scrim.

The default implementation returns 0.0f.

Parameters
parent CoordinatorLayout: the parent view of the given child

child V: the child view above the scrim

Returns
float the desired scrim opacity from 0.0f to 1.0f. The default return value is 0.0f.

Value is between 0.0 and 1.0 inclusive.

getTag

added in version 22.2.0
Object getTag (View child)

Get the behavior-specific tag object with the given child view. This object is stored with the child view's LayoutParams.

Parameters
child View: child view to get tag with

Returns
Object the previously stored tag object

layoutDependsOn

added in version 22.2.0
boolean layoutDependsOn (CoordinatorLayout parent, 
                V child, 
                View dependency)

Determine whether the supplied child view has another specific sibling view as a layout dependency.

This method will be called at least once in response to a layout request. If it returns true for a given child and dependency view pair, the parent CoordinatorLayout will:

  1. Always lay out this child after the dependent child is laid out, regardless of child order.
  2. Call onDependentViewChanged(CoordinatorLayout, V, View) when the dependency view's layout or position changes.

Parameters
parent CoordinatorLayout: the parent view of the given child

child V: the child view to test

dependency View: the proposed dependency of child

Returns
boolean true if child's layout depends on the proposed dependency's layout, false otherwise

See also:

onApplyWindowInsets

added in version 22.2.0
WindowInsetsCompat onApplyWindowInsets (CoordinatorLayout coordinatorLayout, 
                V child, 
                WindowInsetsCompat insets)

Called when the window insets have changed.

Any Behavior associated with the direct child of the CoordinatorLayout may elect to handle the window inset change on behalf of it's associated view.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

insets WindowInsetsCompat: the new window insets.

Returns
WindowInsetsCompat The insets supplied, minus any insets that were consumed

onAttachedToLayoutParams

added in version 24.2.0
void onAttachedToLayoutParams (CoordinatorLayout.LayoutParams params)

Called when the Behavior has been attached to a LayoutParams instance.

This will be called after the LayoutParams has been instantiated and can be modified.

Parameters
params CoordinatorLayout.LayoutParams: the LayoutParams instance that this Behavior has been attached to

onDependentViewChanged

added in version 22.2.0
boolean onDependentViewChanged (CoordinatorLayout parent, 
                V child, 
                View dependency)

Respond to a change in a child's dependent view

This method is called whenever a dependent view changes in size or position outside of the standard layout flow. A Behavior may use this method to appropriately update the child view in response.

A view's dependency is determined by layoutDependsOn(CoordinatorLayout, android.view.View, android.view.View) or if child has set another view as it's anchor.

Note that if a Behavior changes the layout of a child via this method, it should also be able to reconstruct the correct position in onLayoutChild. onDependentViewChanged will not be called during normal layout since the layout of each child view will always happen in dependency order.

If the Behavior changes the child view's size or position, it should return true. The default implementation returns false.

Parameters
parent CoordinatorLayout: the parent view of the given child

child V: the child view to manipulate

dependency View: the dependent view that changed

Returns
boolean true if the Behavior changed the child view's size or position, false otherwise

onDependentViewRemoved

added in version 22.2.1
void onDependentViewRemoved (CoordinatorLayout parent, 
                V child, 
                View dependency)

Respond to a child's dependent view being removed.

This method is called after a dependent view has been removed from the parent. A Behavior may use this method to appropriately update the child view in response.

A view's dependency is determined by layoutDependsOn(CoordinatorLayout, android.view.View, android.view.View) or if child has set another view as it's anchor.

Parameters
parent CoordinatorLayout: the parent view of the given child

child V: the child view to manipulate

dependency View: the dependent view that has been removed

onDetachedFromLayoutParams

added in version 24.2.0
void onDetachedFromLayoutParams ()

Called when the Behavior has been detached from its holding LayoutParams instance.

This will only be called if the Behavior has been explicitly removed from the LayoutParams instance via setBehavior(Behavior). It will not be called if the associated view is removed from the CoordinatorLayout or similar.

onInterceptTouchEvent

added in version 22.2.0
boolean onInterceptTouchEvent (CoordinatorLayout parent, 
                V child, 
                MotionEvent ev)

Respond to CoordinatorLayout touch events before they are dispatched to child views.

Behaviors can use this to monitor inbound touch events until one decides to intercept the rest of the event stream to take an action on its associated child view. This method will return false until it detects the proper intercept conditions, then return true once those conditions have occurred.

Once a Behavior intercepts touch events, the rest of the event stream will be sent to the onTouchEvent(CoordinatorLayout, V, MotionEvent) method.

This method will be called regardless of the visibility of the associated child of the behavior. If you only wish to handle touch events when the child is visible, you should add a check to isShown() on the given child.

The default implementation of this method always returns false.

Parameters
parent CoordinatorLayout: the parent view currently receiving this touch event

child V: the child view associated with this Behavior

ev MotionEvent: the MotionEvent describing the touch event being processed

Returns
boolean true if this Behavior would like to intercept and take over the event stream. The default always returns false.

onLayoutChild

added in version 22.2.0
boolean onLayoutChild (CoordinatorLayout parent, 
                V child, 
                int layoutDirection)

Called when the parent CoordinatorLayout is about the lay out the given child view.

This method can be used to perform custom or modified layout of a child view in place of the default child layout behavior. The Behavior's implementation can delegate to the standard CoordinatorLayout measurement behavior by calling parent.onLayoutChild.

If a Behavior implements onDependentViewChanged(CoordinatorLayout, android.view.View, android.view.View) to change the position of a view in response to a dependent view changing, it should also implement onLayoutChild in such a way that respects those dependent views. onLayoutChild will always be called for a dependent view after its dependency has been laid out.

Parameters
parent CoordinatorLayout: the parent CoordinatorLayout

child V: child view to lay out

layoutDirection int: the resolved layout direction for the CoordinatorLayout, such as LAYOUT_DIRECTION_LTR or LAYOUT_DIRECTION_RTL.

Returns
boolean true if the Behavior performed layout of the child view, false to request default layout behavior

onMeasureChild

added in version 22.2.0
boolean onMeasureChild (CoordinatorLayout parent, 
                V child, 
                int parentWidthMeasureSpec, 
                int widthUsed, 
                int parentHeightMeasureSpec, 
                int heightUsed)

Called when the parent CoordinatorLayout is about to measure the given child view.

This method can be used to perform custom or modified measurement of a child view in place of the default child measurement behavior. The Behavior's implementation can delegate to the standard CoordinatorLayout measurement behavior by calling parent.onMeasureChild.

Parameters
parent CoordinatorLayout: the parent CoordinatorLayout

child V: the child to measure

parentWidthMeasureSpec int: the width requirements for this view

widthUsed int: extra space that has been used up by the parent horizontally (possibly by other children of the parent)

parentHeightMeasureSpec int: the height requirements for this view

heightUsed int: extra space that has been used up by the parent vertically (possibly by other children of the parent)

Returns
boolean true if the Behavior measured the child view, false if the CoordinatorLayout should perform its default measurement

onNestedFling

added in version 22.2.0
boolean onNestedFling (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                float velocityX, 
                float velocityY, 
                boolean consumed)

Called when a nested scrolling child is starting a fling or an action that would be a fling.

Any Behavior associated with the direct child of the CoordinatorLayout may elect to accept the nested scroll as part of onStartNestedScroll(CoordinatorLayout, V, View, View, int). Each Behavior that returned true will receive subsequent nested scroll events for that nested scroll.

onNestedFling is called when the current nested scrolling child view detects the proper conditions for a fling. It reports if the child itself consumed the fling. If it did not, the child is expected to show some sort of overscroll indication. This method should return true if it consumes the fling, so that a child that did not itself take an action in response can choose not to show an overfling indication.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

target View: the descendant view of the CoordinatorLayout performing the nested scroll

velocityX float: horizontal velocity of the attempted fling

velocityY float: vertical velocity of the attempted fling

consumed boolean: true if the nested child view consumed the fling

Returns
boolean true if the Behavior consumed the fling

See also:

onNestedPreFling

added in version 22.2.0
boolean onNestedPreFling (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                float velocityX, 
                float velocityY)

Called when a nested scrolling child is about to start a fling.

Any Behavior associated with the direct child of the CoordinatorLayout may elect to accept the nested scroll as part of onStartNestedScroll(CoordinatorLayout, V, View, View, int). Each Behavior that returned true will receive subsequent nested scroll events for that nested scroll.

onNestedPreFling is called when the current nested scrolling child view detects the proper conditions for a fling, but it has not acted on it yet. A Behavior can return true to indicate that it consumed the fling. If at least one Behavior returns true, the fling should not be acted upon by the child.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

target View: the descendant view of the CoordinatorLayout performing the nested scroll

velocityX float: horizontal velocity of the attempted fling

velocityY float: vertical velocity of the attempted fling

Returns
boolean true if the Behavior consumed the fling

See also:

onNestedPreScroll

added in version 22.2.0
void onNestedPreScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                int dx, 
                int dy, 
                int[] consumed)

This method was deprecated in API level 26.0.0.
You should now override onNestedPreScroll(CoordinatorLayout, View, View, int, int, int[], int). This method will still continue to be called if the type is TYPE_TOUCH.

Parameters
coordinatorLayout CoordinatorLayout

child V

target View

dx int

dy int

consumed int

onNestedPreScroll

added in version 26.0.0
void onNestedPreScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                int dx, 
                int dy, 
                int[] consumed, 
                int type)

Called when a nested scroll in progress is about to update, before the target has consumed any of the scrolled distance.

Any Behavior associated with the direct child of the CoordinatorLayout may elect to accept the nested scroll as part of onStartNestedScroll(CoordinatorLayout, V, View, View, int). Each Behavior that returned true will receive subsequent nested scroll events for that nested scroll.

onNestedPreScroll is called each time the nested scroll is updated by the nested scrolling child, before the nested scrolling child has consumed the scroll distance itself. Each Behavior responding to the nested scroll will receive the same values. The CoordinatorLayout will report as consumed the maximum number of pixels in either direction that any Behavior responding to the nested scroll reported as consumed.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

target View: the descendant view of the CoordinatorLayout performing the nested scroll

dx int: the raw horizontal number of pixels that the user attempted to scroll

dy int: the raw vertical number of pixels that the user attempted to scroll

consumed int: out parameter. consumed[0] should be set to the distance of dx that was consumed, consumed[1] should be set to the distance of dy that was consumed

type int: the type of input which cause this scroll event

See also:

onNestedScroll

added in version 22.2.0
void onNestedScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed)

This method was deprecated in API level 26.0.0.
You should now override onNestedScroll(CoordinatorLayout, View, View, int, int, int, int, int). This method will still continue to be called if the type is TYPE_TOUCH.

Parameters
coordinatorLayout CoordinatorLayout

child V

target View

dxConsumed int

dyConsumed int

dxUnconsumed int

dyUnconsumed int

onNestedScroll

added in version 26.0.0
void onNestedScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed, 
                int type)

Called when a nested scroll in progress has updated and the target has scrolled or attempted to scroll.

Any Behavior associated with the direct child of the CoordinatorLayout may elect to accept the nested scroll as part of onStartNestedScroll(CoordinatorLayout, V, View, View, int). Each Behavior that returned true will receive subsequent nested scroll events for that nested scroll.

onNestedScroll is called each time the nested scroll is updated by the nested scrolling child, with both consumed and unconsumed components of the scroll supplied in pixels. Each Behavior responding to the nested scroll will receive the same values.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

target View: the descendant view of the CoordinatorLayout performing the nested scroll

dxConsumed int: horizontal pixels consumed by the target's own scrolling operation

dyConsumed int: vertical pixels consumed by the target's own scrolling operation

dxUnconsumed int: horizontal pixels not consumed by the target's own scrolling operation, but requested by the user

dyUnconsumed int: vertical pixels not consumed by the target's own scrolling operation, but requested by the user

type int: the type of input which cause this scroll event

See also:

onNestedScrollAccepted

added in version 26.0.0
void onNestedScrollAccepted (CoordinatorLayout coordinatorLayout, 
                V child, 
                View directTargetChild, 
                View target, 
                int axes, 
                int type)

Called when a nested scroll has been accepted by the CoordinatorLayout.

Any Behavior associated with any direct child of the CoordinatorLayout may elect to accept the nested scroll as part of onStartNestedScroll(CoordinatorLayout, V, View, View, int). Each Behavior that returned true will receive subsequent nested scroll events for that nested scroll.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

directTargetChild View: the child view of the CoordinatorLayout that either is or contains the target of the nested scroll operation

target View: the descendant view of the CoordinatorLayout initiating the nested scroll

axes int: the axes that this nested scroll applies to. See SCROLL_AXIS_HORIZONTAL, SCROLL_AXIS_VERTICAL

type int: the type of input which cause this scroll event

See also:

onNestedScrollAccepted

added in version 22.2.0
void onNestedScrollAccepted (CoordinatorLayout coordinatorLayout, 
                V child, 
                View directTargetChild, 
                View target, 
                int axes)

This method was deprecated in API level 26.0.0.
You should now override onNestedScrollAccepted(CoordinatorLayout, View, View, View, int, int). This method will still continue to be called if the type is TYPE_TOUCH.

Parameters
coordinatorLayout CoordinatorLayout

child V

directTargetChild View

target View

axes int

onRequestChildRectangleOnScreen

added in version 24.2.0
boolean onRequestChildRectangleOnScreen (CoordinatorLayout coordinatorLayout, 
                V child, 
                Rect rectangle, 
                boolean immediate)

Called when a child of the view associated with this behavior wants a particular rectangle to be positioned onto the screen.

The contract for this method is the same as requestChildRectangleOnScreen(View, Rect, boolean).

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

rectangle Rect: The rectangle which the child wishes to be on the screen in the child's coordinates

immediate boolean: true to forbid animated or delayed scrolling, false otherwise

Returns
boolean true if the Behavior handled the request

See also:

onRestoreInstanceState

added in version 22.2.0
void onRestoreInstanceState (CoordinatorLayout parent, 
                V child, 
                Parcelable state)

Hook allowing a behavior to re-apply a representation of its internal state that had previously been generated by onSaveInstanceState(CoordinatorLayout, V). This function will never be called with a null state.

Parameters
parent CoordinatorLayout: the parent CoordinatorLayout

child V: child view to restore from

state Parcelable: The frozen state that had previously been returned by onSaveInstanceState(CoordinatorLayout, V).

See also:

onSaveInstanceState

added in version 22.2.0
Parcelable onSaveInstanceState (CoordinatorLayout parent, 
                V child)

Hook allowing a behavior to generate a representation of its internal state that can later be used to create a new instance with that same state. This state should only contain information that is not persistent or can not be reconstructed later.

Behavior state is only saved when both the parent CoordinatorLayout and a view using this behavior have valid IDs set.

Parameters
parent CoordinatorLayout: the parent CoordinatorLayout

child V: child view to restore from

Returns
Parcelable Returns a Parcelable object containing the behavior's current dynamic state.

See also:

onStartNestedScroll

added in version 22.2.0
boolean onStartNestedScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View directTargetChild, 
                View target, 
                int axes)

This method was deprecated in API level 26.0.0.
You should now override onStartNestedScroll(CoordinatorLayout, View, View, View, int, int). This method will still continue to be called if the type is TYPE_TOUCH.

Parameters
coordinatorLayout CoordinatorLayout

child V

directTargetChild View

target View

axes int

Returns
boolean

onStartNestedScroll

added in version 26.0.0
boolean onStartNestedScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View directTargetChild, 
                View target, 
                int axes, 
                int type)

Called when a descendant of the CoordinatorLayout attempts to initiate a nested scroll.

Any Behavior associated with any direct child of the CoordinatorLayout may respond to this event and return true to indicate that the CoordinatorLayout should act as a nested scrolling parent for this scroll. Only Behaviors that return true from this method will receive subsequent nested scroll events.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

directTargetChild View: the child view of the CoordinatorLayout that either is or contains the target of the nested scroll operation

target View: the descendant view of the CoordinatorLayout initiating the nested scroll

axes int: the axes that this nested scroll applies to. See SCROLL_AXIS_HORIZONTAL, SCROLL_AXIS_VERTICAL

type int: the type of input which cause this scroll event

Returns
boolean true if the Behavior wishes to accept this nested scroll

See also:

onStopNestedScroll

added in version 22.2.0
void onStopNestedScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target)

This method was deprecated in API level 26.0.0.
You should now override onStopNestedScroll(CoordinatorLayout, View, View, int). This method will still continue to be called if the type is TYPE_TOUCH.

Parameters
coordinatorLayout CoordinatorLayout

child V

target View

onStopNestedScroll

added in version 26.0.0
void onStopNestedScroll (CoordinatorLayout coordinatorLayout, 
                V child, 
                View target, 
                int type)

Called when a nested scroll has ended.

Any Behavior associated with any direct child of the CoordinatorLayout may elect to accept the nested scroll as part of onStartNestedScroll(CoordinatorLayout, V, View, View, int). Each Behavior that returned true will receive subsequent nested scroll events for that nested scroll.

onStopNestedScroll marks the end of a single nested scroll event sequence. This is a good place to clean up any state related to the nested scroll.

Parameters
coordinatorLayout CoordinatorLayout: the CoordinatorLayout parent of the view this Behavior is associated with

child V: the child view of the CoordinatorLayout this Behavior is associated with

target View: the descendant view of the CoordinatorLayout that initiated the nested scroll

type int: the type of input which cause this scroll event

See also:

onTouchEvent

added in version 22.2.0
boolean onTouchEvent (CoordinatorLayout parent, 
                V child, 
                MotionEvent ev)

Respond to CoordinatorLayout touch events after this Behavior has started intercepting them.

Behaviors may intercept touch events in order to help the CoordinatorLayout manipulate its child views. For example, a Behavior may allow a user to drag a UI pane open or closed. This method should perform actual mutations of view layout state.

This method will be called regardless of the visibility of the associated child of the behavior. If you only wish to handle touch events when the child is visible, you should add a check to isShown() on the given child.

Parameters
parent CoordinatorLayout: the parent view currently receiving this touch event

child V: the child view associated with this Behavior

ev MotionEvent: the MotionEvent describing the touch event being processed

Returns
boolean true if this Behavior handled this touch event and would like to continue receiving events in this stream. The default always returns false.

setTag

added in version 22.2.0
void setTag (View child, 
                Object tag)

Associate a Behavior-specific tag object with the given child view. This object will be stored with the child view's LayoutParams.

Parameters
child View: child view to set tag with

tag Object: tag object to set

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