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CoordinatorLayout

public class CoordinatorLayout
extends ViewGroup implements NestedScrollingParent2, NestedScrollingParent3

java.lang.Object
   ↳ android.view.View
     ↳ android.view.ViewGroup
       ↳ androidx.coordinatorlayout.widget.CoordinatorLayout

CoordinatorLayout is a super-powered FrameLayout.

CoordinatorLayout is intended for two primary use cases:

  1. As a top-level application decor or chrome layout
  2. As a container for a specific interaction with one or more child views

By specifying Behaviors for child views of a CoordinatorLayout you can provide many different interactions within a single parent and those views can also interact with one another. View classes can specify a default behavior when used as a child of a CoordinatorLayout using the CoordinatorLayout.DefaultBehavior annotation.

Behaviors may be used to implement a variety of interactions and additional layout modifications ranging from sliding drawers and panels to swipe-dismissable elements and buttons that stick to other elements as they move and animate.

Children of a CoordinatorLayout may have an anchor. This view id must correspond to an arbitrary descendant of the CoordinatorLayout, but it may not be the anchored child itself or a descendant of the anchored child. This can be used to place floating views relative to other arbitrary content panes.

Children can specify CoordinatorLayout.LayoutParams.insetEdge to describe how the view insets the CoordinatorLayout. Any child views which are set to dodge the same inset edges by CoordinatorLayout.LayoutParams.dodgeInsetEdges will be moved appropriately so that the views do not overlap.

Summary

Nested classes

interface CoordinatorLayout.AttachedBehavior

Defines the default attached CoordinatorLayout.Behavior of a View class

When writing a custom view, implement this interface to return the default behavior when used as a direct child of an CoordinatorLayout. 

class CoordinatorLayout.Behavior<V extends View>

Interaction behavior plugin for child views of CoordinatorLayout. 

@interface CoordinatorLayout.DefaultBehavior

This @interface is deprecated. Use CoordinatorLayout.AttachedBehavior instead  

class CoordinatorLayout.LayoutParams

Parameters describing the desired layout for a child of a CoordinatorLayout. 

class CoordinatorLayout.SavedState

 

Inherited constants

Inherited fields

Public constructors

CoordinatorLayout(Context context)
CoordinatorLayout(Context context, AttributeSet attrs)
CoordinatorLayout(Context context, AttributeSet attrs, int defStyleAttr)

Public methods

void dispatchDependentViewsChanged(View view)

Allows the caller to manually dispatch CoordinatorLayout.Behavior.onDependentViewChanged(CoordinatorLayout, View, View) to the associated CoordinatorLayout.Behavior instances of views which depend on the provided View.

boolean doViewsOverlap(View first, View second)

Check whether two views overlap each other.

CoordinatorLayout.LayoutParams generateLayoutParams(AttributeSet attrs)
List<View> getDependencies(View child)

Returns the list of views which the provided view depends on.

List<View> getDependents(View child)

Returns the list of views which depend on the provided view.

int getNestedScrollAxes()
Drawable getStatusBarBackground()

Gets the drawable used to draw in the insets area for the status bar.

boolean isPointInChildBounds(View child, int x, int y)

Check if a given point in the CoordinatorLayout's coordinates are within the view bounds of the given direct child view.

void onAttachedToWindow()
void onDetachedFromWindow()
void onDraw(Canvas c)
boolean onInterceptTouchEvent(MotionEvent ev)
void onLayoutChild(View child, int layoutDirection)

Called to lay out each individual child view unless a Behavior is present.

void onMeasureChild(View child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed)

Called to measure each individual child view unless a Behavior is present.

boolean onNestedFling(View target, float velocityX, float velocityY, boolean consumed)
boolean onNestedPreFling(View target, float velocityX, float velocityY)
void onNestedPreScroll(View target, int dx, int dy, int[] consumed)
void onNestedPreScroll(View target, int dx, int dy, int[] consumed, int type)

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

void onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed)
void onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type, int[] consumed)

React to a nested scroll in progress.

void onNestedScroll(View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type)

React to a nested scroll in progress.

void onNestedScrollAccepted(View child, View target, int nestedScrollAxes, int type)

React to the successful claiming of a nested scroll operation.

void onNestedScrollAccepted(View child, View target, int nestedScrollAxes)
boolean onStartNestedScroll(View child, View target, int axes, int type)

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

boolean onStartNestedScroll(View child, View target, int nestedScrollAxes)
void onStopNestedScroll(View target)
void onStopNestedScroll(View target, int type)

React to a nested scroll operation ending.

boolean onTouchEvent(MotionEvent ev)
boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate)
void requestDisallowInterceptTouchEvent(boolean disallowIntercept)
void setFitsSystemWindows(boolean fitSystemWindows)
void setOnHierarchyChangeListener(ViewGroup.OnHierarchyChangeListener onHierarchyChangeListener)
void setStatusBarBackground(Drawable bg)

Set a drawable to draw in the insets area for the status bar.

void setStatusBarBackgroundColor(int color)

Set a drawable to draw in the insets area for the status bar.

void setStatusBarBackgroundResource(int resId)

Set a drawable to draw in the insets area for the status bar.

void setVisibility(int visibility)

Protected methods

boolean checkLayoutParams(ViewGroup.LayoutParams p)
boolean drawChild(Canvas canvas, View child, long drawingTime)
void drawableStateChanged()
CoordinatorLayout.LayoutParams generateDefaultLayoutParams()
CoordinatorLayout.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p)
int getSuggestedMinimumHeight()
int getSuggestedMinimumWidth()
void onLayout(boolean changed, int l, int t, int r, int b)
void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
void onRestoreInstanceState(Parcelable state)
Parcelable onSaveInstanceState()
boolean verifyDrawable(Drawable who)

Inherited methods

Public constructors

CoordinatorLayout

public CoordinatorLayout (Context context)

Parameters
context Context

CoordinatorLayout

public CoordinatorLayout (Context context, 
                AttributeSet attrs)

Parameters
context Context

attrs AttributeSet

CoordinatorLayout

public CoordinatorLayout (Context context, 
                AttributeSet attrs, 
                int defStyleAttr)

Parameters
context Context

attrs AttributeSet

defStyleAttr int

Public methods

dispatchDependentViewsChanged

public void dispatchDependentViewsChanged (View view)

Allows the caller to manually dispatch CoordinatorLayout.Behavior.onDependentViewChanged(CoordinatorLayout, View, View) to the associated CoordinatorLayout.Behavior instances of views which depend on the provided View.

You should not normally need to call this method as the it will be automatically done when the view has changed.

Parameters
view View: the View to find dependents of to dispatch the call.

doViewsOverlap

public boolean doViewsOverlap (View first, 
                View second)

Check whether two views overlap each other. The views need to be descendants of this CoordinatorLayout in the view hierarchy.

Parameters
first View: first child view to test
second View: second child view to test
Returns
boolean true if both views are visible and overlap each other

generateLayoutParams

public CoordinatorLayout.LayoutParams generateLayoutParams (AttributeSet attrs)

Parameters
attrs AttributeSet

Returns
CoordinatorLayout.LayoutParams

getDependencies

public List<View> getDependencies (View child)

Returns the list of views which the provided view depends on. Do not store this list as its contents may not be valid beyond the caller.

Parameters
child View: the view to find dependencies for.
Returns
List<View> the list of views which child depends on.

getDependents

public List<View> getDependents (View child)

Returns the list of views which depend on the provided view. Do not store this list as its contents may not be valid beyond the caller.

Parameters
child View: the view to find dependents of.
Returns
List<View> the list of views which depend on child.

getNestedScrollAxes

public int getNestedScrollAxes ()

Returns
int

getStatusBarBackground

public Drawable getStatusBarBackground ()

Gets the drawable used to draw in the insets area for the status bar.

Returns
Drawable The status bar background drawable, or null if none set

isPointInChildBounds

public boolean isPointInChildBounds (View child, 
                int x, 
                int y)

Check if a given point in the CoordinatorLayout's coordinates are within the view bounds of the given direct child view.

Parameters
child View: child view to test
x int: X coordinate to test, in the CoordinatorLayout's coordinate system
y int: Y coordinate to test, in the CoordinatorLayout's coordinate system
Returns
boolean true if the point is within the child view's bounds, false otherwise

onAttachedToWindow

public void onAttachedToWindow ()

onDetachedFromWindow

public void onDetachedFromWindow ()

onDraw

public void onDraw (Canvas c)

Parameters
c Canvas

onInterceptTouchEvent

public boolean onInterceptTouchEvent (MotionEvent ev)

Parameters
ev MotionEvent

Returns
boolean

onLayoutChild

public void onLayoutChild (View child, 
                int layoutDirection)

Called to lay out each individual child view unless a Behavior is present. The Behavior may choose to delegate child measurement to this method.

Parameters
child View: child view to lay out
layoutDirection int: the resolved layout direction for the CoordinatorLayout, such as ViewCompat.LAYOUT_DIRECTION_LTR or ViewCompat.LAYOUT_DIRECTION_RTL.

onMeasureChild

public void onMeasureChild (View child, 
                int parentWidthMeasureSpec, 
                int widthUsed, 
                int parentHeightMeasureSpec, 
                int heightUsed)

Called to measure each individual child view unless a Behavior is present. The Behavior may choose to delegate child measurement to this method.

Parameters
child View: 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)

onNestedFling

public boolean onNestedFling (View target, 
                float velocityX, 
                float velocityY, 
                boolean consumed)

Parameters
target View

velocityX float

velocityY float

consumed boolean

Returns
boolean

onNestedPreFling

public boolean onNestedPreFling (View target, 
                float velocityX, 
                float velocityY)

Parameters
target View

velocityX float

velocityY float

Returns
boolean

onNestedPreScroll

public void onNestedPreScroll (View target, 
                int dx, 
                int dy, 
                int[] consumed)

Parameters
target View

dx int

dy int

consumed int

onNestedPreScroll

public void onNestedPreScroll (View target, 
                int dx, 
                int dy, 
                int[] consumed, 
                int type)

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

onNestedScroll

public void onNestedScroll (View target, 
                int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed)

Parameters
target View

dxConsumed int

dyConsumed int

dxUnconsumed int

dyUnconsumed int

onNestedScroll

public void onNestedScroll (View target, 
                int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed, 
                int type, 
                int[] consumed)

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 NestedScrollingParent2.onStartNestedScroll(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.

This method is called when a nested scrolling child invokes NestedScrollingChild3.dispatchNestedScroll(int, int, int, int, int[], int, int[])} or one of methods it overloads.

An implementation must report how many pixels of the the x and y scroll distances were consumed by this nested scrolling parent by adding the consumed distances to the consumed parameter. If this View also implements NestedScrollingChild3, consumed should also be passed up to it's nested scrolling parent so that the parent may also add any scroll distance it consumes. Index 0 corresponds to dx and index 1 corresponds to dy.

Parameters
target View: The descendant view controlling the nested scroll
dxConsumed int: Horizontal scroll distance in pixels already consumed by target
dyConsumed int: Vertical scroll distance in pixels already consumed by target
dxUnconsumed int: Horizontal scroll distance in pixels not consumed by target
dyUnconsumed int: Vertical scroll distance in pixels not consumed by target
type int: the type of input which cause this scroll event
consumed int: Output. 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

onNestedScroll

public void onNestedScroll (View target, 
                int dxConsumed, 
                int dyConsumed, 
                int dxUnconsumed, 
                int dyUnconsumed, 
                int type)

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(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 View: The descendent view controlling the nested scroll
dxConsumed int: Horizontal scroll distance in pixels already consumed by target
dyConsumed int: Vertical scroll distance in pixels already consumed by target
dxUnconsumed</