public
class
CoordinatorLayout
extends ViewGroup
implements
NestedScrollingParent
java.lang.Object | |||
↳ | android.view.View | ||
↳ | android.view.ViewGroup | ||
↳ | android.support.design.widget.CoordinatorLayout |
CoordinatorLayout is a super-powered FrameLayout
.
CoordinatorLayout is intended for two primary use cases:
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
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.
Nested classes | |
---|---|
class |
CoordinatorLayout.Behavior<V extends View>
Interaction behavior plugin for child views of |
@interface |
CoordinatorLayout.DefaultBehavior
Defines the default |
class |
CoordinatorLayout.LayoutParams
Parameters describing the desired layout for a child of a |
class |
CoordinatorLayout.SavedState
|
Inherited XML attributes | |
---|---|
From
class
android.view.ViewGroup
| |
From
class
android.view.View
|
Inherited constants |
---|
From
class
android.view.ViewGroup
|
From
class
android.view.View
|
Inherited fields |
---|
From
class
android.view.View
|
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
|
boolean
|
doViewsOverlap(View first, View second)
Check whether two views overlap each other. |
CoordinatorLayout.LayoutParams
|
generateLayoutParams(AttributeSet attrs)
Returns a new set of layout parameters based on the supplied attributes set. |
List<View>
|
getDependencies(View child)
Returns the list of views which the provided view depends on. |
int
|
getNestedScrollAxes()
Return the current axes of nested scrolling for this ViewGroup. |
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()
This is called when the view is attached to a window. |
void
|
onDetachedFromWindow()
This is called when the view is detached from a window. |
void
|
onDraw(Canvas c)
Implement this to do your drawing. |
boolean
|
onInterceptTouchEvent(MotionEvent ev)
Implement this method to intercept all touch screen motion events. |
void
|
onLayoutChild(View child, int layoutDirection)
Called to lay out each individual child view unless a
|
void
|
onMeasureChild(View child, int parentWidthMeasureSpec, int widthUsed, int parentHeightMeasureSpec, int heightUsed)
Called to measure each individual child view unless a
|
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)
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)
React to a nested scroll in progress. |
void
|
onNestedScrollAccepted(View child, View target, int nestedScrollAxes)
React to the successful claiming of a nested scroll operation. |
boolean
|
onStartNestedScroll(View child, View target, int nestedScrollAxes)
React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate. |
void
|
onStopNestedScroll(View target)
React to a nested scroll operation ending. |
boolean
|
onTouchEvent(MotionEvent ev)
Implement this method to handle touch screen motion events. |
void
|
requestDisallowInterceptTouchEvent(boolean disallowIntercept)
Called when a child does not want this parent and its ancestors to
intercept touch events with
|
void
|
setFitsSystemWindows(boolean fitSystemWindows)
Sets whether or not this view should account for system screen decorations
such as the status bar and inset its content; that is, controlling whether
the default implementation of |
void
|
setOnHierarchyChangeListener(ViewGroup.OnHierarchyChangeListener onHierarchyChangeListener)
Register a callback to be invoked when a child is added to or removed from this view. |
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)
Set the enabled state of this view. |
Protected methods | |
---|---|
boolean
|
checkLayoutParams(ViewGroup.LayoutParams p)
|
boolean
|
drawChild(Canvas canvas, View child, long drawingTime)
Draw one child of this View Group. |
void
|
drawableStateChanged()
This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown. |
CoordinatorLayout.LayoutParams
|
generateDefaultLayoutParams()
Returns a set of default layout parameters. |
CoordinatorLayout.LayoutParams
|
generateLayoutParams(ViewGroup.LayoutParams p)
Returns a safe set of layout parameters based on the supplied layout params. |
int
|
getSuggestedMinimumHeight()
Returns the suggested minimum height that the view should use. |
int
|
getSuggestedMinimumWidth()
Returns the suggested minimum width that the view should use. |
void
|
onLayout(boolean changed, int l, int t, int r, int b)
Called from layout when this view should assign a size and position to each of its children. |
void
|
onMeasure(int widthMeasureSpec, int heightMeasureSpec)
Measure the view and its content to determine the measured width and the measured height. |
void
|
onRestoreInstanceState(Parcelable state)
Hook allowing a view to re-apply a representation of its internal state that had previously
been generated by |
Parcelable
|
onSaveInstanceState()
Hook allowing a view to generate a representation of its internal state that can later be used to create a new instance with that same state. |
boolean
|
verifyDrawable(Drawable who)
If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying. |
Inherited methods | |
---|---|
From
class
android.view.ViewGroup
| |
From
class
android.view.View
| |
From
class
java.lang.Object
| |
From
interface
android.view.ViewParent
| |
From
interface
android.view.ViewManager
| |
From
interface
android.graphics.drawable.Drawable.Callback
| |
From
interface
android.view.KeyEvent.Callback
| |
From
interface
android.view.accessibility.AccessibilityEventSource
| |
From
interface
android.support.v4.view.NestedScrollingParent
|
CoordinatorLayout (Context context, AttributeSet attrs)
Parameters | |
---|---|
context |
Context
|
attrs |
AttributeSet
|
CoordinatorLayout (Context context, AttributeSet attrs, int defStyleAttr)
Parameters | |
---|---|
context |
Context
|
attrs |
AttributeSet
|
defStyleAttr |
int
|
void dispatchDependentViewsChanged (View view)
Allows the caller to manually dispatch
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.
|
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 |
CoordinatorLayout.LayoutParams generateLayoutParams (AttributeSet attrs)
Returns a new set of layout parameters based on the supplied attributes set.
Parameters | |
---|---|
attrs |
AttributeSet :
the attributes to build the layout parameters from |
Returns | |
---|---|
CoordinatorLayout.LayoutParams |
an instance of ViewGroup.LayoutParams or one
of its descendants
|
List<View> getDependencies (View child)
Returns the list of views which the provided view depends on. Do not store this list as it's 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.
|
int getNestedScrollAxes ()
Return the current axes of nested scrolling for this ViewGroup.
A ViewGroup returning something other than SCROLL_AXIS_NONE
is currently
acting as a nested scrolling parent for one or more descendant views in the hierarchy.
Returns | |
---|---|
int |
Flags indicating the current axes of nested scrolling |
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 |
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 |
void onAttachedToWindow ()
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 onDraw(android.graphics.Canvas)
,
however it may be called any time before the first onDraw -- including
before or after onMeasure(int, int)
.
void onDetachedFromWindow ()
This is called when the view is detached from a window. At this point it no longer has a surface for drawing.
void onDraw (Canvas c)
Implement this to do your drawing.
Parameters | |
---|---|
c |
Canvas :
the canvas on which the background will be drawn
|
boolean onInterceptTouchEvent (MotionEvent ev)
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:
ACTION_CANCEL
, and all further
events will be delivered to your onTouchEvent() method and no longer
appear here.
Parameters | |
---|---|
ev |
MotionEvent :
The motion event being dispatched down the hierarchy. |
Returns | |
---|---|
boolean |
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. |
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
LAYOUT_DIRECTION_LTR or
LAYOUT_DIRECTION_RTL .
|
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)
|
boolean onNestedFling (View target, float velocityX, float velocityY, boolean consumed)
Request a fling from a nested scroll.
This method signifies that a nested scrolling child has detected suitable conditions
for a fling. Generally this means that a touch scroll has ended with a
velocity
in the direction of scrolling that meets or exceeds
the minimum fling velocity
along a scrollable axis.
If a nested scrolling child view would normally fling but it is at the edge of its own content, it can use this method to delegate the fling to its nested scrolling parent instead. The parent may optionally consume the fling or observe a child fling.
Parameters | |
---|---|
target |
View :
View that initiated the nested scroll |
velocityX |
float :
Horizontal velocity in pixels per second |
velocityY |
float :
Vertical velocity in pixels per second |
consumed |
boolean :
true if the child consumed the fling, false otherwise |
Returns | |
---|---|
boolean |
true if this parent consumed or otherwise reacted to the fling |
boolean onNestedPreFling (View target, float velocityX, float velocityY)
React to a nested fling before the target view consumes it.
This method siginfies that a nested scrolling child has detected a fling with the given
velocity along each axis. Generally this means that a touch scroll has ended with a
velocity
in the direction of scrolling that meets or exceeds
the minimum fling velocity
along a scrollable axis.
If a nested scrolling parent is consuming motion as part of a
pre-scroll
, it may be appropriate for
it to also consume the pre-fling to complete that same motion. By returning
true
from this method, the parent indicates that the child should not
fling its own internal content as well.
Parameters | |
---|---|
target |
View :
View that initiated the nested scroll |
velocityX |
float :
Horizontal velocity in pixels per second |
velocityY |
float :
Vertical velocity in pixels per second |
Returns | |
---|---|
boolean |
true if this parent consumed the fling ahead of the target view |
void onNestedPreScroll (View target, int dx, int dy, int[] consumed)
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
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
|
void onNestedScroll (View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed)
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)
.
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 |
int :
Horizontal scroll distance in pixels not consumed by target |
dyUnconsumed |
int :
Vertical scroll distance in pixels not consumed by target
|
void onNestedScrollAccepted (View child, View target, int nestedScrollAxes)
React to the successful claiming of a nested scroll operation.
This method will be called after
onStartNestedScroll
returns true. It offers
an opportunity for the view and its superclasses to perform initial configuration
for the nested scroll. Implementations of this method should always call their superclass's
implementation of this method if one is present.
Parameters | |
---|---|
child |
View :
Direct child of this ViewParent containing target |
target |
View :
View that initiated the nested scroll |
nestedScrollAxes |
int :
Flags consisting of SCROLL_AXIS_HORIZONTAL ,
SCROLL_AXIS_VERTICAL or both |
boolean onStartNestedScroll (View child, View target, int nestedScrollAxes)
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
startNestedScroll(int)
. Each parent up the view hierarchy will be
given an opportunity to respond and claim the nested scrolling operation by returning
true
.
This method may be overridden by ViewParent implementations to indicate when the view
is willing to support a nested scrolling operation that is about to begin. If it returns
true, this ViewParent will become the target view's nested scrolling parent for the duration
of the scroll operation in progress. When the nested scroll is finished this ViewParent
will receive a call to onStopNestedScroll(View)
.
Parameters | |
---|---|
child |
View :
Direct child of this ViewParent containing target |
target |
View :
View that initiated the nested scroll |
nestedScrollAxes |
int :
Flags consisting of SCROLL_AXIS_HORIZONTAL ,
SCROLL_AXIS_VERTICAL or both |
Returns | |
---|---|
boolean |
true if this ViewParent accepts the nested scroll operation |
void onStopNestedScroll (View target)
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 ACTION_UP
or ACTION_CANCEL
event.
Implementations of this method should always call their superclass's implementation of this
method if one is present.
Parameters | |
---|---|
target |
View :
View that initiated the nested scroll
|
boolean onTouchEvent (MotionEvent ev)
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
performClick()
. This will ensure consistent system behavior,
including:
ACTION_CLICK
when
accessibility features are enabled
Parameters | |
---|---|
ev |
MotionEvent :
The motion event. |
Returns | |
---|---|
boolean |
True if the event was handled, false otherwise. |
void requestDisallowInterceptTouchEvent (boolean disallowIntercept)
Called when a child does not want this parent and its ancestors to
intercept touch events with
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.
Parameters | |
---|---|
disallowIntercept |
boolean :
True if the child does not want the parent to
intercept touch events.
|
void setFitsSystemWindows (boolean fitSystemWindows)
Sets whether or not this view should account for system screen decorations
such as the status bar and inset its content; that is, controlling whether
the default implementation of fitSystemWindows(Rect)
will be
executed. See that method for more details.
Note that if you are providing your own implementation of
fitSystemWindows(Rect)
, then there is no need to set this
flag to true -- your implementation will be overriding the default
implementation that checks this flag.
Parameters | |
---|---|
fitSystemWindows |
boolean :
If true, then the default implementation of
fitSystemWindows(Rect) will be executed. |
void setOnHierarchyChangeListener (ViewGroup.OnHierarchyChangeListener onHierarchyChangeListener)
Register a callback to be invoked when a child is added to or removed from this view.
Parameters | |
---|---|
onHierarchyChangeListener |
ViewGroup.OnHierarchyChangeListener :
the callback to invoke on hierarchy change
|
void setStatusBarBackground (Drawable bg)
Set a drawable to draw in the insets area for the status bar. Note that this will only be activated if this DrawerLayout fitsSystemWindows.
Parameters | |
---|---|
bg |
Drawable :
Background drawable to draw behind the status bar
|
void setStatusBarBackgroundColor (int color)
Set a drawable to draw in the insets area for the status bar. Note that this will only be activated if this DrawerLayout fitsSystemWindows.
Parameters | |
---|---|
color |
int :
Color to use as a background drawable to draw behind the status bar
in 0xAARRGGBB format.
|
void setStatusBarBackgroundResource (int resId)
Set a drawable to draw in the insets area for the status bar. Note that this will only be activated if this DrawerLayout fitsSystemWindows.
Parameters | |
---|---|
resId |
int :
Resource id of a background drawable to draw behind the status bar
|
void setVisibility (int visibility)
Set the enabled state of this view.
Parameters | |
---|---|
visibility |
int :
One of VISIBLE , INVISIBLE , or GONE . |
boolean checkLayoutParams (ViewGroup.LayoutParams p)
Parameters | |
---|---|
p |
ViewGroup.LayoutParams
|
Returns | |
---|---|
boolean |
boolean drawChild (Canvas canvas, View child, long drawingTime)
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.
Parameters | |
---|---|
canvas |
Canvas :
The canvas on which to draw the child |
child |
View :
Who to draw |
drawingTime |
long :
The time at which draw is occurring |
Returns | |
---|---|
boolean |
True if an invalidate() was issued |
void drawableStateChanged ()
This function is called whenever the state of the view changes in such a way that it impacts the state of drawables being shown.
If the View has a StateListAnimator, it will also be called to run necessary state change animations.
Be sure to call through to the superclass when overriding this function.
CoordinatorLayout.LayoutParams generateDefaultLayoutParams ()
Returns a set of default layout parameters. These parameters are requested
when the View passed to addView(View)
has no layout parameters
already set. If null is returned, an exception is thrown from addView.
Returns | |
---|---|
CoordinatorLayout.LayoutParams |
a set of default layout parameters or null |
CoordinatorLayout.LayoutParams generateLayoutParams (ViewGroup.LayoutParams p)
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
checkLayoutParams(android.view.ViewGroup.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.
Parameters | |
---|---|
p |
ViewGroup.LayoutParams :
The layout parameters to convert into a suitable set of layout parameters
for this ViewGroup. |
Returns | |
---|---|
CoordinatorLayout.LayoutParams |
an instance of ViewGroup.LayoutParams or one
of its descendants
|
int getSuggestedMinimumHeight ()
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
(getMinimumHeight()
).
When being used in onMeasure(int, int)
, the caller should still
ensure the returned height is within the requirements of the parent.
Returns | |
---|---|
int |
The suggested minimum height of the view. |
int getSuggestedMinimumWidth ()
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
(getMinimumWidth()
).
When being used in onMeasure(int, int)
, the caller should still
ensure the returned width is within the requirements of the parent.
Returns | |
---|---|
int |
The suggested minimum width of the view. |
void onLayout (boolean changed, int l, int t, int r, int b)
Called from layout 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.
Parameters | |
---|---|
changed |
boolean :
This is a new size or position for this view |
l |
int :
Left position, relative to parent |
t |
int :
Top position, relative to parent |
r |
int :
Right position, relative to parent |
b |
int :
Bottom position, relative to parent
|
void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
Measure the view and its content to determine the measured width and the
measured height. This method is invoked by 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 setMeasuredDimension(int, int)
to store the
measured width and height of this view. Failure to do so will trigger an
IllegalStateException
, thrown by
measure(int, int)
. Calling the superclass'
onMeasure(int, int)
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 onMeasure(int, int)
to provide better measurements of
their content.
If this method is overridden, it is the subclass's responsibility to make
sure the measured height and width are at least the view's minimum height
and width (getSuggestedMinimumHeight()
and
getSuggestedMinimumWidth()
).
Parameters | |
---|---|
widthMeasureSpec |
int :
horizontal space requirements as imposed by the parent.
The requirements are encoded with
View.MeasureSpec . |
heightMeasureSpec |
int :
vertical space requirements as imposed by the parent.
The requirements are encoded with
View.MeasureSpec . |
void onRestoreInstanceState (Parcelable state)
Hook allowing a view to re-apply a representation of its internal state that had previously
been generated by onSaveInstanceState()
. This function will never be called with a
null state.
Parameters | |
---|---|
state |
Parcelable :
The frozen state that had previously been returned by
onSaveInstanceState() . |
Parcelable onSaveInstanceState ()
Hook allowing a view 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. For example, you will never store your current position on screen because that will be computed again when a new instance of the view is placed in its view hierarchy.
Some examples of things you may store here: the current cursor position in a text view (but usually not the text itself since that is stored in a content provider or other persistent storage), the currently selected item in a list view.
Returns | |
---|---|
Parcelable |
Returns a Parcelable object containing the view's current dynamic state, or null if there is nothing interesting to save. The default implementation returns null. |
boolean verifyDrawable (Drawable who)
If your view subclass is displaying its own Drawable objects, it should override this function and return true for any Drawable it is displaying. This allows animations for those drawables to be scheduled.
Be sure to call through to the super class when overriding this function.
Parameters | |
---|---|
who |
Drawable :
The Drawable to verify. Return true if it is one you are
displaying, else return the result of calling through to the
super class. |
Returns | |
---|---|
boolean |
boolean If true than the Drawable is being displayed in the view; else false and it is not allowed to animate. |