Set a new adapter to provide child views on demand. <p> When adapter is changed, all existing views are recycled back to the pool. If the pool has onl

Replaces the current adapter with the new one and triggers listeners. @param adapter The new adapter @param compatibleWithPrevious If true, the new ad

Defines whether the layout should be measured by the RecyclerView or the LayoutManager wants to handle the layout measurements itself. <p> This method

This method is here so that we can control the important for a11y changes and test it.

设置adapter中所有的内容都变化了

Sets the {@link #left}, {@link #top}, {@link #right} and {@link #bottom} values from the given ViewHolder. Clears all {@link #changeFlags}. @param ho

Enable or disable layout and scroll. After <code>setLayoutFrozen(true)</code> is called, Layout requests will be postponed until <code>setLayoutFroze

Called after a layout is calculated during a measure pass when using auto-measure. <p> It simply traverses all children to calculate a bounding box th

从下往上绘制 @param reverseLayout

RecyclerView internally does its own View measurement caching which should help with WRAP_CONTENT. <p> Use this method if the View is not yet measured

Similar to {@link #stopScroll()} but does not set the state.

Attempts to bind view, and account for relevant timing information. If deadlineNs != FOREVER_NS, this method may fail to bind, and return false. @par

Used for debugging. Validates that child views are laid out in correct order. This is important because rest of the algorithm relies on this constrain

Add a listener that will be notified of any changes in scroll state or position. <p>Components that add a listener should take care to remove it when

Called by the RecyclerView when a ViewHolder is added to the layout. <p> In detail, this means that the ViewHolder was <b>not</b> a child when the lay

Called by the RecyclerView when a ViewHolder has disappeared from the layout. <p> This means that the View was a child of the LayoutManager when layou

Called by the RecyclerView when a ViewHolder is present in both before and after the layout and RecyclerView has not received a {@link Adapter#notifyI

Checks if RecyclerView is in the middle of a layout or scroll and throws an {@link IllegalStateException} if it <b>is</b>. @param message The message

Reattach a previously {@link #detachView(android.view.View) detached} view. This method should not be used to reattach views that were previously {@li

This method internally calls {@link #onBindViewHolder(ViewHolder, int)} to update the {@link ViewHolder} contents with the item at the given position

Converts a focusDirection to orientation. @param focusDirection One of {@link View#FOCUS_UP}, {@link View#FOCUS_DOWN}, {@link V

Creates a horizontal OrientationHelper for the given LayoutManager. @param layoutManager The LayoutManager to attach to. @return A new OrientationHel

Instantiate and set a LayoutManager, if specified in the attributes.

Test overrides this to plug some tracking and verification. @return A new LayoutState

Creates an OrientationHelper for the given LayoutManager and orientation. @param layoutManager LayoutManager to attach to @param orientation Desire

Creates a vertical OrientationHelper for the given LayoutManager. @param layoutManager The LayoutManager to attach to. @return A new OrientationHelpe

This method calls {@link #onCreateViewHolder(ViewGroup, int)} to create a new {@link ViewHolder} and initializes some private fields to be used by Rec

Temporarily detach and scrap all currently attached child views. Views will be scrapped into the given Recycler. The Recycler may prefer to reuse scra

重置一些参数

@return True if ViewHolder is not referenced by RecyclerView animations but has transient state which will prevent it from being recycled.

Returns the ViewHolder that contains the given view. @param view The view that is a descendant of the RecyclerView. @return The ViewHolder that cont

Returns the adapter position of the first visible view. This position does not include adapter changes that were dispatched after the last layout pass

Returns the adapter position of the last visible view. This position does not include adapter changes that were dispatched after the last layout pass.

Utility method for finding an internal RecyclerView, if present

Finds the best view candidate to request focus on using mFocusedItemPosition index of the previously focused item. It first traverses the adapter forw

Among the children that are suitable to be considered as an anchor child, returns the one closest to the end of the layout. <p> Due to ambiguous adapt

Among the children that are suitable to be considered as an anchor child, returns the one closest to the start of the layout. <p> Due to ambiguous ada

Finds the view which represents the given adapter position. <p> This method traverses each child since it has no information about child order. Overri

@see RecyclerView.LayoutManager#findViewByPosition(int)

Return the ViewHolder for the item with the given id. The RecyclerView must use an Adapter with {@link Adapter#setHasStableIds(boolean) stableIds} to

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

Return the adapter position that the given child view corresponds to. @param child Child View to query @return Adapter position corresponding to the

Return the adapter position of the given child view as of the latest completed layout pass. <p> This position may not be equal to Item's adapter posit

Returns the scroll amount that brings the given rect in child's coordinate system within the padded area of RecyclerView. @param parent The parent Rec

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

Returns the total number of items in the data set held by the adapter. @return The total number of items in this adapter.

Returns an {@link ItemDecoration} previously added to this RecyclerView. @param index The index position of the desired ItemDecoration. @return the I

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

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

When LayoutManager supports animations, RecyclerView tracks 3 positions for ViewHolders to perform animations. <p> If a ViewHolder was laid out in the

Parse the xml attributes to get the most common properties used by layout managers. @attr ref android.support.v7.recyclerview.R.styleable#RecyclerVie

Retrieve this RecyclerView's {@link RecycledViewPool}. This method will never return null; if no pool is set for this view a new one will be created.

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