belongs to Maven artifact com.android.support:coordinatorlayout:28.0.0-alpha1
CoordinatorLayout.Behavior
public
static
abstract
class
CoordinatorLayout.Behavior
extends Object
java.lang.Object | |
↳ | android.support.design.widget.CoordinatorLayout.Behavior<V extends android.view.View> |
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 | |
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CoordinatorLayout.Behavior()
Default constructor for instantiating Behaviors. |
|
CoordinatorLayout.Behavior(Context context, AttributeSet attrs)
Default constructor for inflating Behaviors from layout. |
Public methods | |
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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 26.1.0.
You should now override
|
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 26.1.0.
You should now override
|
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 26.1.0.
You should now override
|
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 |
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 26.1.0.
You should now override
|
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 26.1.0.
You should now override
|
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
|
static
void
|
setTag(View child, Object tag)
Associate a Behavior-specific tag object with the given child view. |
Inherited methods | |
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java.lang.Object
|
Public constructors
CoordinatorLayout.Behavior
CoordinatorLayout.Behavior ()
Default constructor for instantiating Behaviors.
CoordinatorLayout.Behavior
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
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, View)
would return > 0.0f.
Parameters | |
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parent |
CoordinatorLayout : the parent view of the given child |
child |
V : the child view to test |
Returns | |
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boolean |
true if getScrimOpacity(CoordinatorLayout, View) would
return > 0.0f.
|
getInsetDodgeRect
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 | |
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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 | |
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boolean |
true the rect was updated, false if we should use the child's bounds |
getScrimColor
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 | |
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parent |
CoordinatorLayout : the parent view of the given child |
child |
V : the child view above the scrim |
Returns | |
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int |
the desired scrim color in 0xAARRGGBB format. The default return value is
BLACK . |
See also:
getScrimOpacity
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 | |
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parent |
CoordinatorLayout : the parent view of the given child |
child |
V : the child view above the scrim |
Returns | |
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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
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 | |
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child |
View : child view to get tag with |
Returns | |
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Object |
the previously stored tag object |
layoutDependsOn
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:
- Always lay out this child after the dependent child is laid out, regardless of child order.
- Call
onDependentViewChanged(CoordinatorLayout, V, View)
when the dependency view's layout or position changes.
Parameters | |
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parent |
CoordinatorLayout : the parent view of the given child |
child |
V : the child view to test |
dependency |
View : the proposed dependency of child |
Returns | |
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boolean |
true if child's layout depends on the proposed dependency's layout, false otherwise |
onApplyWindowInsets
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 | |
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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 | |
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WindowInsetsCompat |
The insets supplied, minus any insets that were consumed |
onAttachedToLayoutParams
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 | |
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params |
CoordinatorLayout.LayoutParams : the LayoutParams instance that this Behavior has been attached to
|
onDependentViewChanged
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, 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 | |
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parent |
CoordinatorLayout : the parent view of the given child |
child |
V : the child view to manipulate |
dependency |
View : the dependent view that changed |
Returns | |
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boolean |
true if the Behavior changed the child view's size or position, false otherwise |
onDependentViewRemoved
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, View, View)
or
if child
has set another view as it's anchor.
Parameters | |
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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
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
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 | |
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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 | |
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boolean |
true if this Behavior would like to intercept and take over the event stream. The default always returns false. |
onLayoutChild
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, 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 | |
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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 | |
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boolean |
true if the Behavior performed layout of the child view, false to request default layout behavior |
onMeasureChild
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
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 | |
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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 |
onNestedPreFling
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: