Returns the number of rows for accessibility. <p> Default implementation returns the number of items in the adapter if LayoutManager supports vertical

Returns an unmodifiable list of ViewHolders that are currently in the scrap list. @return List of ViewHolders in the scrap list.

Returns a view for the position either from attach scrap, hidden children, or cache. @param position Item position @param dryRun Does a dry run, fin

Return the current scrolling state of the RecyclerView. @return {@link #SCROLL_STATE_IDLE}, {@link #SCROLL_STATE_DRAGGING} or {@link #SCROLL_STATE_SE

Returns the selection mode for accessibility. Should be {@link AccessibilityNodeInfoCompat.CollectionInfoCompat#SELECTION_MODE_NONE}, {@link Accessibi

Returns the total height of item decorations applied to child's top. <p> Note that this value is not updated until the View is measured or {@link #cal

Obtain a view initialized for the given position. This method should be used by {@link LayoutManager} implementations to obtain views to represent da

Returns a View that can be binded to the given Adapter position. <p> This method should <b>not</b> create a new View. Instead, it is expected to retur

This handles the case where there is an unexpected VH missing in the pre-layout map. <p> We might be able to detect the error in the application which

当前的位置不在顶并且不在可绘制的区域的底部 @param state @return

Returns true if one or more observers are attached to this adapter. @return true if this adapter has observers

Returns if current scroll has a target position. @return true if scroll is being triggered to make a certain position visible @see #getTargetScrollPos

@return True if an existing view holder needs to be updated

Returns whether the currently focused child stays within RV's bounds with the given amount of scrolling. @param parent The parent RecyclerView. @param

Returns whether layout is hierarchical or not to be used for accessibility. <p> Default implementation returns false. @param recycler The Recycler th

Checks if the new focus candidate is a good enough candidate such that RecyclerView will assign it as the next focus View instead of letting view hier

@return True if SmoothScroller is currently active

@return true if RecycylerView is currently in the state of smooth scrolling.

Returns true if the view this LayoutParams is attached to is now representing potentially invalid data. A LayoutManager should scrap/recycle it. @ret

Lay out the given child view within the RecyclerView using coordinates that include any current {@link ItemDecoration ItemDecorations} and margins. <

If necessary, layouts new items for predictive animations

Mark all known views as invalid. Used in response to a, "the whole world might have changed" data change event.

Measure a child view using standard measurement policy, taking the padding of the parent RecyclerView, any added item decorations and the child margin

Moves a View from one position to another. @param fromIndex The View's initial index @param toIndex The View's target index

Gets the view for the next element that we should layout. Also updates current item index to the next item, based on {@link #mItemDirection} @return

Returns the next item from the scrap list. <p> Upon finding a valid VH, sets current item position to VH.itemPosition + mItemDirection @return View i

Notify any registered observers that the data set has changed. <p>There are two different classes of data change events, item changes and structural

Notify any registered observers that the item at <code>position</code> has changed. Equivalent to calling <code>notifyItemChanged(position, null);</co

Notify any registered observers that the currently reflected <code>itemCount</code> items starting at <code>positionStart</code> have been newly inser

Notify any registered observers that the <code>itemCount</code> items previously located at <code>positionStart</code> have been removed from the data

Notify any registered observers that the item previously located at <code>position</code> has been removed from the data set. The items previously loc

Called to populate focusable views within the RecyclerView. <p>The LayoutManager implementation should return <code>true</code> if the default behavi

Method called when Anchor position is decided. Extending class can setup accordingly or even update anchor info if necessary. @param recycler

Called after {@link #dispatchAnimationFinished(ViewHolder)} is called by the ItemAnimator. @param viewHolder The ViewHolder whose animation is finish

Called when a new animation is started on the given ViewHolder. @param viewHolder The ViewHolder which started animating. Note that the ViewHolder

Called by RecyclerView when it starts observing this Adapter. <p> Keep in mind that same adapter may be observed by multiple RecyclerViews. @param re

Called when this LayoutManager is both attached to a RecyclerView and that RecyclerView is attached to a window. <p> If the RecyclerView is re-attache

Called by RecyclerView to display the data at the specified position. This method should update the contents of the {@link ViewHolder#itemView} to ref

Called when an item view is detached from this RecyclerView. <p>Subclasses of RecyclerView may want to perform extra bookkeeping or modifications of

Called when a view is attached to the RecyclerView. @param view The View which is attached to the RecyclerView

Called when a view is detached from RecyclerView. @param view The View which is being detached from the RecyclerView

Called when RecyclerView needs a new {@link ViewHolder} of the given type to represent an item. <p> This new ViewHolder should be constructed with a n

Called by RecyclerView when it stops observing this Adapter. @param recyclerView The RecyclerView instance which stopped observing this adapter. @see

@deprecated override {@link #onDetachedFromWindow(RecyclerView, Recycler)}

Draw any appropriate decorations into the Canvas supplied to the RecyclerView. Any content drawn by this method will be drawn after the item views are

Called when the child view enters the hidden state

Called by the RecyclerView if a ViewHolder created by this Adapter cannot be recycled due to its transient state. Upon receiving this callback, Adapte

Override this to handle a fling given the velocities in both x and y directions. Note that this method will only be called if the associated {@link La

Returns the index of the child to draw for this iteration. Override this if you want to change the drawing order of children. By default, it returns i

This method gives a LayoutManager an opportunity to intercept the initial focus search before the default behavior of {@link FocusFinder} is used. If

Called when items have been added to the adapter. The LayoutManager may choose to requestLayout if the inserted items would require refreshing the cur

Called when {@link Adapter#notifyDataSetChanged()} is triggered instead of giving detailed information on what has actually changed. @param recyclerV

Called when an item is moved withing the adapter. <p> Note that, an item may also change position in response to another ADD/REMOVE/MOVE operation. Th

Called when items have been removed from the adapter. @param recyclerView @param positionStart @param itemCount

Called when items have been changed in the adapter. To receive payload, override {@link #onItemsUpdated(RecyclerView, int, int, Object)} instead, the

Call this method after onLayout method is complete if state is NOT pre-layout. This method records information like layout bounds that might be useful

Called after a full layout calculation is finished. The layout calculation may include multiple {@link #onLayoutChildren(Recycler, State)} calls due t

Called when the child view leaves the hidden state

@deprecated Use {@link #onRequestChildFocus(RecyclerView, State, View, View)}

Called when a child of RecyclerView does not want RecyclerView and its ancestors to intercept touch events with {@link ViewGroup#onInterceptTouchEvent

<p>RecyclerView will call this method each time it scrolls until it can find the target position in the layout.</p> <p>SmoothScroller should check dx,

Called when smooth scroll is started. This might be a good time to do setup.

Called when smooth scroller is stopped. This is a good place to cleanup your state etc. @see #stop()

Called when the target position is laid out. This is the last callback SmoothScroller will receive and it should update the provided {@link Action} to

Process a touch event as part of a gesture that was claimed by returning true from a previous call to {@link #onInterceptTouchEvent}. @param e Motion

Called when a view created by this adapter has been attached to a window. <p>This can be used as a reasonable signal that the view is about to be see

Called when a view created by this adapter has been detached from its window. <p>Becoming detached from the window is not necessarily a permanent con

Apply a pull to relevant overscroll glow effects

Adds a mapping from the specified id to the specified value, replacing the previous mapping from the specified key if there was one. @param resourceI