Package icyllis.modernui.widget

Class CoordinatorLayout

java.lang.Object

icyllis.modernui.view.View

icyllis.modernui.view.ViewGroup

icyllis.modernui.widget.CoordinatorLayout

All Implemented Interfaces:

Drawable.Callback, ViewManager, ViewParent

public class CoordinatorLayout
extends ViewGroup

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 by implementing the CoordinatorLayout.AttachedBehavior interface.

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.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	CoordinatorLayout.AttachedBehavior	Defines the default attached CoordinatorLayout.Behavior of a View class
static class	CoordinatorLayout.Behavior<V extends View>	Interaction behavior plugin for child views of CoordinatorLayout.
static @interface	CoordinatorLayout.DispatchChangeEvent
static class	CoordinatorLayout.LayoutParams	Parameters describing the desired layout for a child of a CoordinatorLayout.

Nested classes/interfaces inherited from class icyllis.modernui.view.ViewGroup

ViewGroup.MarginLayoutParams

Nested classes/interfaces inherited from class icyllis.modernui.view.View

View.DragShadow, View.Focusable, View.FocusableMode, View.FocusDirection, View.FocusRealDirection, View.LayoutDir, View.NestedScrollType, View.OnAttachStateChangeListener, View.OnClickListener, View.OnContextClickListener, View.OnCreateContextMenuListener, View.OnDragListener, View.OnFocusChangeListener, View.OnGenericMotionListener, View.OnHoverListener, View.OnKeyListener, View.OnLayoutChangeListener, View.OnLongClickListener, View.OnScrollChangeListener, View.OnTouchListener, View.ResolvedLayoutDir, View.ScrollAxis, View.ScrollBarStyle, View.ScrollIndicators, View.TextAlignment, View.Visibility

Field Summary

Fields inherited from class icyllis.modernui.view.ViewGroup

CLIP_TO_PADDING_MASK, FLAG_DISALLOW_INTERCEPT, FOCUS_AFTER_DESCENDANTS, FOCUS_BEFORE_DESCENDANTS, FOCUS_BLOCK_DESCENDANTS

Fields inherited from class icyllis.modernui.view.View

ALPHA, BOTTOM, EMPTY_STATE_SET, ENABLED_FOCUSED_SELECTED_STATE_SET, ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, ENABLED_FOCUSED_STATE_SET, ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET, ENABLED_SELECTED_STATE_SET, ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET, ENABLED_STATE_SET, ENABLED_WINDOW_FOCUSED_STATE_SET, FOCUS_BACKWARD, FOCUS_DOWN, FOCUS_FORWARD, FOCUS_LEFT, FOCUS_RIGHT, FOCUS_UP, FOCUSABLE, FOCUSABLE_AUTO, FOCUSABLES_ALL, FOCUSABLES_TOUCH_MODE, FOCUSED_SELECTED_STATE_SET, FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, FOCUSED_STATE_SET, FOCUSED_WINDOW_FOCUSED_STATE_SET, GONE, HAPTIC_FEEDBACK_ENABLED, INVISIBLE, LAYOUT_DIRECTION_INHERIT, LAYOUT_DIRECTION_LOCALE, LAYOUT_DIRECTION_LTR, LAYOUT_DIRECTION_RTL, LAYOUT_DIRECTION_UNDEFINED, LEFT, MEASURED_HEIGHT_STATE_SHIFT, MEASURED_SIZE_MASK, MEASURED_STATE_MASK, MEASURED_STATE_TOO_SMALL, NO_ID, NOT_FOCUSABLE, OVER_SCROLL_ALWAYS, OVER_SCROLL_IF_CONTENT_SCROLLS, OVER_SCROLL_NEVER, PRESSED_ENABLED_FOCUSED_SELECTED_STATE_SET, PRESSED_ENABLED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_ENABLED_FOCUSED_STATE_SET, PRESSED_ENABLED_FOCUSED_WINDOW_FOCUSED_STATE_SET, PRESSED_ENABLED_SELECTED_STATE_SET, PRESSED_ENABLED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_ENABLED_STATE_SET, PRESSED_ENABLED_WINDOW_FOCUSED_STATE_SET, PRESSED_FOCUSED_SELECTED_STATE_SET, PRESSED_FOCUSED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_FOCUSED_STATE_SET, PRESSED_FOCUSED_WINDOW_FOCUSED_STATE_SET, PRESSED_SELECTED_STATE_SET, PRESSED_SELECTED_WINDOW_FOCUSED_STATE_SET, PRESSED_STATE_SET, PRESSED_WINDOW_FOCUSED_STATE_SET, RIGHT, ROTATION, ROTATION_X, ROTATION_Y, SCALE_X, SCALE_Y, SCROLL_AXIS_HORIZONTAL, SCROLL_AXIS_NONE, SCROLL_AXIS_VERTICAL, SCROLL_INDICATOR_BOTTOM, SCROLL_INDICATOR_END, SCROLL_INDICATOR_LEFT, SCROLL_INDICATOR_RIGHT, SCROLL_INDICATOR_START, SCROLL_INDICATOR_TOP, SCROLL_X, SCROLL_Y, SCROLLBARS_INSIDE_INSET, SCROLLBARS_INSIDE_OVERLAY, SCROLLBARS_OUTSIDE_INSET, SCROLLBARS_OUTSIDE_OVERLAY, SELECTED_STATE_SET, SELECTED_WINDOW_FOCUSED_STATE_SET, SOUND_EFFECTS_ENABLED, TEXT_ALIGNMENT_CENTER, TEXT_ALIGNMENT_GRAVITY, TEXT_ALIGNMENT_INHERIT, TEXT_ALIGNMENT_TEXT_END, TEXT_ALIGNMENT_TEXT_START, TEXT_ALIGNMENT_VIEW_END, TEXT_ALIGNMENT_VIEW_START, TEXT_DIRECTION_ANY_RTL, TEXT_DIRECTION_FIRST_STRONG, TEXT_DIRECTION_FIRST_STRONG_LTR, TEXT_DIRECTION_FIRST_STRONG_RTL, TEXT_DIRECTION_INHERIT, TEXT_DIRECTION_LOCALE, TEXT_DIRECTION_LTR, TEXT_DIRECTION_RTL, TOP, TRANSLATION_X, TRANSLATION_Y, TRANSLATION_Z, TYPE_NON_TOUCH, TYPE_TOUCH, VIEW_MARKER, VISIBLE, WINDOW_FOCUSED_STATE_SET, X, Y, Z

Constructor Summary

Constructors

Constructor	Description
CoordinatorLayout(Context context)

Method Summary

Modifier and Type	Method	Description
protected boolean	checkLayoutParams(ViewGroup.LayoutParams p)	Check whether given params fit to this view group.
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.
protected void	drawChild(Canvas canvas, View child, long drawingTime)	Draw one child of this View Group.
protected CoordinatorLayout.LayoutParams	generateDefaultLayoutParams()	Returns a set of default layout parameters.
protected CoordinatorLayout.LayoutParams	generateLayoutParams(ViewGroup.LayoutParams p)	Returns a safe set of layout parameters based on the supplied layout params.
List<View>	getDependencies(View child)	Returns a new list containing the views on which the provided view depends.
final @UnmodifiableView List<View>	getDependencySortedChildren()
List<View>	getDependents(View child)	Returns a new list of views which depend on the provided view.
protected int	getSuggestedMinimumHeight()	Returns the suggested minimum height that the view should use.
protected int	getSuggestedMinimumWidth()	Returns the suggested minimum width that the view should use.
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()	This is called when the view is attached to a window.
void	onDetachedFromWindow()	This is called when the view is detached from a window.
boolean	onInterceptTouchEvent(MotionEvent ev)	Implement this method to intercept all touch screen motion events.
protected void	onLayout(boolean changed, int l, int t, int r, int b)	Called from View.layout(int, int, int, int) when this view should assign a size and position to each of its children.
void	onLayoutChild(View child, int layoutDirection)	Called to lay out each individual child view unless a Behavior is present.
protected void	onMeasure(int widthMeasureSpec, int heightMeasureSpec)	Measure the view and its content to determine the measured width and the measured height.
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)	Request a fling from a nested scroll.
boolean	onNestedPreFling(View target, float velocityX, float velocityY)	React to a nested fling before the target view consumes it.
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, int type, int[] consumed)	React to a nested scroll in progress.
void	onNestedScrollAccepted(View child, View target, int axes, int type)	React to the successful claiming of a nested scroll operation.
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.
void	onStopNestedScroll(View target, int type)	React to a nested scroll operation ending.
boolean	onTouchEvent(MotionEvent ev)	Implement this method to handle touch screen motion events.
protected void	onViewRemoved(View child)	Called when a child view is removed from this ViewGroup.
boolean	requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate)	Called when a child of this group wants a particular rectangle to be positioned onto the screen.
void	requestDisallowInterceptTouchEvent(boolean disallowIntercept)	Called when a child does not want this parent and its ancestors to intercept touch events with ViewGroup.onInterceptTouchEvent(MotionEvent).

Methods inherited from class icyllis.modernui.view.ViewGroup

addFocusables, addKeyboardNavigationClusters, addStatesFromChildren, addTouchables, addTransientView, addView, addView, addView, addView, addView, addViewInLayout, addViewInLayout, attachViewToParent, bringChildToFront, childDrawableStateChanged, childHasTransientStateChanged, cleanupLayoutState, clearChildFocus, clearDisappearingChildren, clearFocus, detachAllViewsFromParent, detachViewFromParent, detachViewFromParent, detachViewsFromParent, dispatchDraw, dispatchDrawableHotspotChanged, dispatchFinishTemporaryDetach, dispatchGenericPointerEvent, dispatchHoverEvent, dispatchKeyEvent, dispatchKeyShortcutEvent, dispatchSetActivated, dispatchSetPressed, dispatchSetSelected, dispatchStartTemporaryDetach, dispatchTouchEvent, dispatchVisibilityChanged, dispatchWindowFocusChanged, dispatchWindowVisibilityChanged, drawableStateChanged, endViewTransition, findFocus, focusableViewAvailable, focusSearch, getChildAt, getChildCount, getChildDrawingOrder, getChildDrawingOrder, getChildMeasureSpec, getChildVisibleRect, getChildVisibleRect, getClipChildren, getClipToPadding, getDescendantFocusability, getFocusedChild, getLayoutTransition, getNestedScrollAxes, getTouchscreenBlocksFocus, getTransientView, getTransientViewCount, getTransientViewIndex, hasBooleanFlag, hasFocus, hasTransientState, indexOfChild, internalSetPadding, invalidateChild, invalidateChildInParent, isChildrenDrawingOrderEnabled, isLayoutSuppressed, isTransitionGroup, jumpDrawablesToCurrentState, layout, measureChild, measureChildren, measureChildWithMargins, offsetChildrenTopAndBottom, offsetDescendantRectToMyCoords, offsetRectIntoDescendantCoords, onChildVisibilityChanged, onCreateDrawableState, onInterceptHoverEvent, onRequestFocusInDescendants, onResolvePointerIcon, onSetLayoutParams, onViewAdded, removeAllViews, removeAllViewsInLayout, removeDetachedView, removeTransientView, removeView, removeViewAt, removeViewInLayout, removeViews, removeViewsInLayout, requestChildFocus, requestFocus, requestTransitionStart, resetResolvedDrawables, resolveDrawables, resolveLayoutDirection, resolveLayoutParams, resolvePadding, resolveRtlPropertiesIfNeeded, resolveTextAlignment, resolveTextDirection, restoreDefaultFocus, setAddStatesFromChildren, setBooleanFlag, setChildrenDrawingOrderEnabled, setClipChildren, setClipToPadding, setDescendantFocusability, setLayoutTransition, setShadowAlpha, setTouchscreenBlocksFocus, setTransitionGroup, shouldDelayChildPressedState, showContextMenuForChild, startActionModeForChild, startViewTransition, suppressLayout, transformPointToViewLocal, updateViewLayout

Methods inherited from class icyllis.modernui.view.View

addFocusables, addOnAttachStateChangeListener, addOnLayoutChangeListener, awakenScrollBars, awakenScrollBars, callOnClick, cancelLongPress, cancelPendingInputEvents, canReceivePointerEvents, canResolveLayoutDirection, canResolveTextAlignment, canResolveTextDirection, canScrollHorizontally, canScrollVertically, combineMeasuredStates, computeHorizontalScrollExtent, computeHorizontalScrollOffset, computeHorizontalScrollRange, computeScroll, computeVerticalScrollExtent, computeVerticalScrollOffset, computeVerticalScrollRange, createContextMenu, dispatchGenericMotionEvent, dispatchNestedFling, dispatchNestedPreFling, dispatchNestedPreScroll, dispatchNestedScroll, dispatchPointerEvent, dp, draw, drawableHotspotChanged, findViewById, findViewByPredicate, findViewByPredicateInsideOut, findViewWithTag, focusSearch, forceHasOverlappingRendering, forceLayout, generateViewId, getAlpha, getAnimationMatrix, getBackground, getBaseline, getBottom, getBoundsOnScreen, getBoundsOnScreen, getClipBounds, getClipBounds, getContentDescription, getContext, getContextMenuInfo, getDefaultSize, getDrawableState, getDrawingRect, getElevation, getFadingEdge, getFadingEdgeLength, getFocusable, getFocusables, getFocusedRect, getForeground, getForegroundGravity, getGlobalVisibleRect, getGlobalVisibleRect, getHandler, getHasOverlappingRendering, getHeight, getHitRect, getHorizontalScrollbarHeight, getHorizontalScrollbarThumbDrawable, getHorizontalScrollbarTrackDrawable, getId, getInverseMatrix, getKeyDispatcherState, getLayoutDirection, getLayoutParams, getLeft, getLocalVisibleRect, getLocationInWindow, getLocationOnScreen, getMatrix, getMeasuredHeight, getMeasuredHeightAndState, getMeasuredState, getMeasuredWidth, getMeasuredWidthAndState, getMinimumHeight, getMinimumWidth, getNextClusterForwardId, getNextFocusDownId, getNextFocusForwardId, getNextFocusLeftId, getNextFocusRightId, getNextFocusUpId, getOnFocusChangeListener, getOnLongClickListener, getOutlineProvider, getOverScrollMode, getPaddingBottom, getPaddingEnd, getPaddingLeft, getPaddingRight, getPaddingStart, getPaddingTop, getParent, getPivotX, getPivotY, getRawLayoutDirection, getRawTextAlignment, getRawTextDirection, getRevealOnFocusHint, getRight, getRootView, getRotation, getRotationX, getRotationY, getScaleX, getScaleY, getScrollBarDefaultDelayBeforeFade, getScrollBarFadeDuration, getScrollBarSize, getScrollBarStyle, getScrollIndicators, getScrollX, getScrollY, getStateDescription, getStateListAnimator, getTag, getTag, getTextAlignment, getTextDirection, getTooltipText, getTooltipView, getTop, getTouchables, getTransitionAlpha, getTransitionName, getTranslationX, getTranslationY, getTranslationZ, getVerticalFadingEdgeLength, getVerticalScrollbarThumbDrawable, getVerticalScrollbarTrackDrawable, getVerticalScrollbarWidth, getViewRoot, getViewTreeObserver, getVisibility, getWidth, getWindowAttachCount, getWindowVisibility, getX, getY, getZ, handleScrollBarDragging, hasExplicitFocusable, hasFocusable, hasIdentityMatrix, hasNestedScrollingParent, hasOnClickListeners, hasOnLongClickListeners, hasOverlappingRendering, hasTranslationTransientState, hasWindowFocus, invalidate, invalidate, invalidate, invalidateDrawable, invalidateOutline, isActivated, isAttachedToWindow, isClickable, isContextClickable, isDuplicateParentStateEnabled, isEnabled, isFocusable, isFocusableInTouchMode, isFocused, isFocusedByDefault, isForegroundInsidePadding, isHapticFeedbackEnabled, isHorizontalFadingEdgeEnabled, isHorizontalScrollBarEnabled, isHovered, isInLayout, isInScrollingContainer, isInTouchMode, isKeyboardNavigationCluster, isLaidOut, isLayoutDirectionInherited, isLayoutDirectionResolved, isLayoutRequested, isLayoutRtl, isLongClickable, isNestedScrollingEnabled, isPaddingRelative, isPivotSet, isPressed, isRootNamespace, isScrollbarFadingEnabled, isSelected, isShowingLayoutBounds, isShown, isSoundEffectsEnabled, isTemporarilyDetached, isTextAlignmentInherited, isTextAlignmentResolved, isTextDirectionInherited, isTextDirectionResolved, isVerticalFadingEdgeEnabled, isVerticalScrollBarEnabled, isVerticalScrollBarHidden, keyboardNavigationClusterSearch, mapRectFromViewToScreenCoords, measure, mergeDrawableStates, offsetLeftAndRight, offsetTopAndBottom, onCancelPendingInputEvents, onCreateContextMenu, onDragEvent, onDraw, onDrawForeground, onDrawScrollBars, onFinishTemporaryDetach, onFocusChanged, onGenericMotionEvent, onHoverChanged, onHoverEvent, onKeyDown, onKeyShortcut, onKeyUp, onOverScrolled, onResolveDrawables, onRtlPropertiesChanged, onScrollChanged, onSizeChanged, onStartTemporaryDetach, onVisibilityAggregated, onVisibilityChanged, onWindowFocusChanged, onWindowVisibilityChanged, overScrollBy, performButtonActionOnTouchDown, performClick, performContextClick, performContextClick, performHapticFeedback, performHapticFeedback, performLongClick, performLongClick, playSoundEffect, pointInView, post, postDelayed, postInvalidate, postInvalidateDelayed, postInvalidateOnAnimation, postOnAnimation, postOnAnimationDelayed, refreshDrawableState, removeCallbacks, removeOnAttachStateChangeListener, removeOnLayoutChangeListener, requestFocus, requestFocus, requestLayout, requestRectangleOnScreen, requestRectangleOnScreen, requireViewById, resetPivot, resolveSize, resolveSizeAndState, scheduleDrawable, scrollBy, scrollTo, setActivated, setAlpha, setAnimationMatrix, setBackground, setBottom, setClickable, setClipBounds, setContentDescription, setContextClickable, setDuplicateParentStateEnabled, setElevation, setEnabled, setFocusable, setFocusable, setFocusableInTouchMode, setFocusedByDefault, setFocusedInCluster, setForeground, setForegroundGravity, setFrame, setHapticFeedbackEnabled, setHasTransientState, setHasTranslationTransientState, setHorizontalFadingEdgeEnabled, setHorizontalScrollBarEnabled, setHorizontalScrollbarThumbDrawable, setHorizontalScrollbarTrackDrawable, setHovered, setId, setIsRootNamespace, setKeyboardNavigationCluster, setLayoutDirection, setLayoutParams, setLeft, setLongClickable, setMeasuredDimension, setMinimumHeight, setMinimumWidth, setNestedScrollingEnabled, setNextClusterForwardId, setNextFocusDownId, setNextFocusForwardId, setNextFocusLeftId, setNextFocusRightId, setNextFocusUpId, setOnClickListener, setOnContextClickListener, setOnCreateContextMenuListener, setOnDragListener, setOnFocusChangeListener, setOnGenericMotionListener, setOnHoverListener, setOnKeyListener, setOnLongClickListener, setOnScrollChangeListener, setOnTouchListener, setOutlineProvider, setOverScrollMode, setPadding, setPaddingRelative, setPivotX, setPivotY, setPressed, setRevealOnFocusHint, setRight, setRotation, setRotationX, setRotationY, setScaleX, setScaleY, setScrollBarDefaultDelayBeforeFade, setScrollBarFadeDuration, setScrollbarFadingEnabled, setScrollBarSize, setScrollBarStyle, setScrollIndicators, setScrollIndicators, setScrollX, setScrollY, setSelected, setSoundEffectsEnabled, setStateDescription, setStateListAnimator, setTag, setTag, setTextAlignment, setTextDirection, setTooltipText, setTop, setTransitionAlpha, setTransitionName, setTransitionVisibility, setTranslationX, setTranslationY, setTranslationZ, setVerticalFadingEdgeEnabled, setVerticalScrollBarEnabled, setVerticalScrollbarThumbDrawable, setVerticalScrollbarTrackDrawable, setVisibility, setWillNotDraw, setX, setY, setZ, showContextMenu, showContextMenu, sp, startActionMode, startActionMode, startDragAndDrop, startNestedScroll, stopNestedScroll, toGlobalMotionEvent, toLocalMotionEvent, toString, transformFromViewToWindowSpace, transformMatrixToGlobal, transformMatrixToLocal, unscheduleDrawable, unscheduleDrawable, verifyDrawable, willNotDraw

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface icyllis.modernui.view.ViewParent

canResolveLayoutDirection, canResolveTextAlignment, canResolveTextDirection, createContextMenu, getLayoutDirection, getParent, getTextAlignment, getTextDirection, isLayoutDirectionResolved, isLayoutRequested, isTextAlignmentResolved, isTextDirectionResolved, keyboardNavigationClusterSearch, requestLayout

Constructor Details

CoordinatorLayout

public CoordinatorLayout(Context context)

Method Details

onAttachedToWindow

public void onAttachedToWindow()

Description copied from class: View

This is called when the view is attached to a window. At this point it has a Surface and will start drawing. Note that this function is guaranteed to be called before View.onDraw(Canvas), however it may be called any time before the first onDraw -- including before or after View.onMeasure(int, int).

Overrides:

onAttachedToWindow in class View

See Also:

• View.onDetachedFromWindow()

onDetachedFromWindow

public void onDetachedFromWindow()

Description copied from class: View

This is called when the view is detached from a window. At this point it no longer has a surface for drawing.

Overrides:

onDetachedFromWindow in class View

See Also:

• View.onAttachedToWindow()

onInterceptTouchEvent

public boolean onInterceptTouchEvent(@NonNull
 MotionEvent ev)

Description copied from class: ViewGroup

Implement this method to intercept all touch screen motion events. This allows you to watch events as they are dispatched to your children, and take ownership of the current gesture at any point.

Using this function takes some care, as it has a fairly complicated interaction with View.onTouchEvent(MotionEvent), and using it requires implementing that method as well as this one in the correct way. Events will be received in the following order:

1. You will receive the down event here.
2. The down event will be handled either by a child of this view group, or given to your own onTouchEvent() method to handle; this means you should implement onTouchEvent() to return true, so you will continue to see the rest of the gesture (instead of looking for a parent view to handle it). Also, by returning true from onTouchEvent(), you will not receive any following events in onInterceptTouchEvent() and all touch processing must happen in onTouchEvent() like normal.
3. For as long as you return false from this function, each following event (up to and including the final up) will be delivered first here and then to the target's onTouchEvent().
4. If you return true from here, you will not receive any following events: the target view will receive the same event but with the action MotionEvent.ACTION_CANCEL, and all further events will be delivered to your onTouchEvent() method and no longer appear here.

Overrides:

onInterceptTouchEvent in class ViewGroup

Parameters:

ev - The motion event being dispatched down the hierarchy.

Returns:

Return true to steal motion events from the children and have them dispatched to this ViewGroup through onTouchEvent(). The current target will receive an ACTION_CANCEL event, and no further messages will be delivered here.

onTouchEvent

public boolean onTouchEvent(@NonNull
 MotionEvent ev)

Description copied from class: View

Implement this method to handle touch screen motion events.

If this method is used to detect click actions, it is recommended that the actions be performed by implementing and calling View.performClick(). This will ensure consistent system behavior.

Overrides:

onTouchEvent in class View

Parameters:

ev - the touch event

Returns:

true if the event was handled by the view, false otherwise

requestDisallowInterceptTouchEvent

public void requestDisallowInterceptTouchEvent(boolean disallowIntercept)

Description copied from interface: ViewParent

Called when a child does not want this parent and its ancestors to intercept touch events with ViewGroup.onInterceptTouchEvent(MotionEvent).

This parent should pass this call onto its parents. This parent must obey this request for the duration of the touch (that is, only clear the flag after this parent has received an up or a cancel.

Specified by:

requestDisallowInterceptTouchEvent in interface ViewParent

Overrides:

requestDisallowInterceptTouchEvent in class ViewGroup

Parameters:

disallowIntercept - True if the child does not want the parent to intercept touch events.

getSuggestedMinimumWidth

protected int getSuggestedMinimumWidth()

Description copied from class: View

Returns the suggested minimum width that the view should use. This returns the maximum of the view's minimum width and the background's minimum width (Drawable.getMinimumWidth()).

When being used in View.onMeasure(int, int), the caller should still ensure the returned width is within the requirements of the parent.

Overrides:

getSuggestedMinimumWidth in class View

Returns:

The suggested minimum width of the view.

getSuggestedMinimumHeight

protected int getSuggestedMinimumHeight()

Description copied from class: View

Returns the suggested minimum height that the view should use. This returns the maximum of the view's minimum height and the background's minimum height (Drawable.getMinimumHeight()).

When being used in View.onMeasure(int, int), the caller should still ensure the returned height is within the requirements of the parent.

Overrides:

getSuggestedMinimumHeight in class View

Returns:

The suggested minimum height of the view.

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 - the child to measure

parentWidthMeasureSpec - the width requirements for this view

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

parentHeightMeasureSpec - the height requirements for this view

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

onMeasure

protected void onMeasure(int widthMeasureSpec,
 int heightMeasureSpec)

Description copied from class: View

Measure the view and its content to determine the measured width and the measured height. This method is invoked by View.measure(int, int) and should be overridden by subclasses to provide accurate and efficient measurement of their contents.

CONTRACT: When overriding this method, you must call View.setMeasuredDimension(int, int) to store the measured width and height of this view. Failure to do so will trigger an IllegalStateException, thrown by View.measure(int, int). Calling super.onMeasure() is a valid use.

The base class implementation of measure defaults to the background size, unless a larger size is allowed by the MeasureSpec. Subclasses should override the base one to provide better measurements of their content.

Overrides:

onMeasure in class View

Parameters:

widthMeasureSpec - width measure specification imposed by the parent MeasureSpec

heightMeasureSpec - height measure specification imposed by the parent MeasureSpec

onLayoutChild

public void onLayoutChild(@NonNull
 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 - child view to lay out

layoutDirection - the resolved layout direction for the CoordinatorLayout, such as View.LAYOUT_DIRECTION_LTR or View.LAYOUT_DIRECTION_RTL.

onLayout

protected void onLayout(boolean changed,
 int l,
 int t,
 int r,
 int b)

Description copied from class: View

Called from View.layout(int, int, int, int) when this view should assign a size and position to each of its children.

Derived classes with children should override this method and call layout on each of their children.

Specified by:

onLayout in class ViewGroup

Parameters:

changed - This is a new size or position for this view

l - Left position, relative to parent

t - Top position, relative to parent

r - Right position, relative to parent

b - Bottom position, relative to parent

drawChild

protected void drawChild(@NonNull
 Canvas canvas,
 @NonNull
 View child,
 long drawingTime)

Description copied from class: ViewGroup

Draw one child of this View Group. This method is responsible for getting the canvas in the right state. This includes clipping, translating so that the child's scrolled origin is at 0, 0, and applying any animation transformations.

Overrides:

drawChild in class ViewGroup

Parameters:

canvas - The canvas on which to draw the child

child - Who to draw

drawingTime - The time at which draw is occurring

dispatchDependentViewsChanged

public void dispatchDependentViewsChanged(@NonNull
 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 - the View to find dependents of to dispatch the call.

getDependencies

@NonNull
public List<View> getDependencies(@NonNull
 View child)

Returns a new list containing the views on which the provided view depends.

Parameters:

child - the view to find dependencies for

Returns:

a new list of views on which child depends

getDependents

@NonNull
public List<View> getDependents(@NonNull
 View child)

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

Parameters:

child - the view to find dependents of

Returns:

a new list of views which depend on child

getDependencySortedChildren

@NonNull
@VisibleForTesting
public final @UnmodifiableView List<View> getDependencySortedChildren()

isPointInChildBounds

public boolean isPointInChildBounds(@NonNull
 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 - child view to test

x - X coordinate to test, in the CoordinatorLayout's coordinate system

y - Y coordinate to test, in the CoordinatorLayout's coordinate system

Returns:

true if the point is within the child view's bounds, false otherwise

doViewsOverlap

public boolean doViewsOverlap(@NonNull
 View first,
 @NonNull
 View second)

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

Parameters:

first - first child view to test

second - second child view to test

Returns:

true if both views are visible and overlap each other

onViewRemoved

protected void onViewRemoved(View child)

Description copied from class: ViewGroup

Called when a child view is removed from this ViewGroup. Overrides should always call super.onViewRemoved.

Overrides:

onViewRemoved in class ViewGroup

Parameters:

child - the removed child view

requestChildRectangleOnScreen

public boolean requestChildRectangleOnScreen(@NonNull
 View child,
 Rect rectangle,
 boolean immediate)

Description copied from interface: ViewParent

Called when a child of this group wants a particular rectangle to be positioned onto the screen. ViewGroups overriding this can trust that:

• child will be a direct child of this group
• rectangle will be in the child's content coordinates

ViewGroups overriding this should uphold the contract:

• nothing will change if the rectangle is already visible
• the view port will be scrolled only just enough to make the rectangle visible

Specified by:

requestChildRectangleOnScreen in interface ViewParent

Overrides:

requestChildRectangleOnScreen in class ViewGroup

Parameters:

child - The direct child making the request.

rectangle - The rectangle in the child's coordinates the child wishes to be on the screen.

immediate - True to forbid animated or delayed scrolling, false otherwise

Returns:

Whether the group scrolled to handle the operation

generateLayoutParams

@NonNull
protected CoordinatorLayout.LayoutParams generateLayoutParams(@NonNull
 ViewGroup.LayoutParams p)

Description copied from class: ViewGroup

Returns a safe set of layout parameters based on the supplied layout params. When a ViewGroup is passed a View whose layout params do not pass the test of ViewGroup.checkLayoutParams(LayoutParams), this method is invoked. This method should return a new set of layout params suitable for this ViewGroup, possibly by copying the appropriate attributes from the specified set of layout params.

Overrides:

generateLayoutParams in class ViewGroup

Parameters:

p - The layout parameters to convert into a suitable set of layout parameters for this ViewGroup.

Returns:

an instance of ViewGroup.LayoutParams or one of its descendants

generateDefaultLayoutParams

@NonNull
protected CoordinatorLayout.LayoutParams generateDefaultLayoutParams()

Description copied from class: ViewGroup

Returns a set of default layout parameters. These parameters are requested when the View passed to ViewGroup.addView(View) has no layout parameters already set. If null is returned, an exception is thrown from addView.

Overrides:

generateDefaultLayoutParams in class ViewGroup

Returns:

a set of default layout parameters

checkLayoutParams

protected boolean checkLayoutParams(ViewGroup.LayoutParams p)

Description copied from class: ViewGroup

Check whether given params fit to this view group.

See also ViewGroup.generateLayoutParams(LayoutParams) See also ViewGroup.generateDefaultLayoutParams()

Overrides:

checkLayoutParams in class ViewGroup

Parameters:

p - layout params to check

Returns:

if params matched to this view group

onStartNestedScroll

public boolean onStartNestedScroll(@NonNull
 View child,
 @NonNull
 View target,
 int axes,
 int type)

Description copied from interface: ViewParent

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 View.startNestedScroll(int, 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 ViewParent.onStopNestedScroll(View, int).

Specified by:

onStartNestedScroll in interface ViewParent

Overrides:

onStartNestedScroll in class ViewGroup

Parameters:

child - Direct child of this ViewParent containing target

target - View that initiated the nested scroll

axes - Flags consisting of View.SCROLL_AXIS_HORIZONTAL, View.SCROLL_AXIS_VERTICAL or both

type - the type of input which cause this scroll event

Returns:

true if this ViewParent accepts the nested scroll operation

onNestedScrollAccepted

public void onNestedScrollAccepted(@NonNull
 View child,
 @NonNull
 View target,
 int axes,
 int type)

Description copied from interface: ViewParent

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 superclasses' implementation of this method if one is present.

Specified by:

onNestedScrollAccepted in interface ViewParent

Overrides:

onNestedScrollAccepted in class ViewGroup

Parameters:

child - Direct child of this ViewParent containing target

target - View that initiated the nested scroll

axes - Flags consisting of View.SCROLL_AXIS_HORIZONTAL, View.SCROLL_AXIS_VERTICAL or both

type - the type of input which cause this scroll event

See Also:

• ViewParent.onStartNestedScroll(View, View, int, int)
• ViewParent.onStopNestedScroll(View, int)

onStopNestedScroll

public void onStopNestedScroll(@NonNull
 View target,
 int type)

Description copied from interface: ViewParent

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 superclasses' implementation of this method if one is present.

Specified by:

onStopNestedScroll in interface ViewParent

Overrides:

onStopNestedScroll in class ViewGroup

Parameters:

target - View that initiated the nested scroll

type - the type of input which cause this scroll event

onNestedScroll

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

Description copied from interface: ViewParent

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 ViewParent.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 View.dispatchNestedScroll(int, int, int, int, int[], int, int[])} or one of methods it overloads.

An implementation must report how many pixels of the x and y scroll distances were consumed by this nested scrolling parent by adding the consumed distances to the consumed parameter. 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.

Specified by:

onNestedScroll in interface ViewParent

Overrides:

onNestedScroll in class ViewGroup

Parameters:

target - The descendant view controlling the nested scroll

dxConsumed - Horizontal scroll distance in pixels already consumed by target

dyConsumed - Vertical scroll distance in pixels already consumed by target

dxUnconsumed - Horizontal scroll distance in pixels not consumed by target

dyUnconsumed - Vertical scroll distance in pixels not consumed by target

type - the type of input which cause this scroll event

consumed - 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

See Also:

• View.dispatchNestedScroll(int, int, int, int, int[], int, int[])

onNestedPreScroll

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

Description copied from interface: ViewParent

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[], 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.

Specified by:

onNestedPreScroll in interface ViewParent

Overrides:

onNestedPreScroll in class ViewGroup

Parameters:

target - View that initiated the nested scroll

dx - Horizontal scroll distance in pixels

dy - Vertical scroll distance in pixels

consumed - Output. The horizontal and vertical scroll distance consumed by this parent

type - the type of input which cause this scroll event

onNestedFling

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

Description copied from interface: ViewParent

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.

Specified by:

onNestedFling in interface ViewParent

Overrides:

onNestedFling in class ViewGroup

Parameters:

target - View that initiated the nested scroll

velocityX - Horizontal velocity in pixels per second

velocityY - Vertical velocity in pixels per second

consumed - true if the child consumed the fling, false otherwise

Returns:

true if this parent consumed or otherwise reacted to the fling

onNestedPreFling

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

Description copied from interface: ViewParent

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

This method signifies 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.

Specified by:

onNestedPreFling in interface ViewParent

Overrides:

onNestedPreFling in class ViewGroup

Parameters:

target - View that initiated the nested scroll

velocityX - Horizontal velocity in pixels per second

velocityY - Vertical velocity in pixels per second

Returns:

true if this parent consumed the fling ahead of the target view