FLEX的TREE组件源码解读（二）

public class Tree extends List implements IIMESupport{    include "../core/Version.as";

    private var IS_NEW_ROW_STYLE:Object =    {        depthColors: true,        indentation: true,        disclosureOpenIcon: true,        disclosureClosedIcon: true,        folderOpenIcon: true,        folderClosedIcon: true,        defaultLeafIcon: true    };

    mx_internal static var createAccessibilityImplementation:Function;

 

    //构造函数

    public function Tree()    {        super();

        itemRenderer = new ClassFactory(TreeItemRenderer);        editorXOffset = 12;        editorWidthOffset = -12;                addEventListener(TreeEvent.ITEM_OPENING, expandItemHandler,                         false, EventPriority.DEFAULT_HANDLER);    }

    //节点是否在展开中

    private var opening:Boolean;

    //动画对象

    private var tween:Object;

    //遮罩LIST

    private var maskList:Array;

    //水平滚动条位置

    private var _userMaxHorizontalScrollPosition:Number = 0;

    /**     *  @private     */    private var eventPending:Object;

    /**     *  @private     */    private var eventAfterTween:Object;

 /**  *  @private  */ private var oldLength:int = -1;   /**  *  @private  */ private var expandedItem:Object;

 /**  *  @private  */ private var bSelectedItemRemoved:Boolean = false;       /**     *  @private     *  Used to slow the scrolling down a bit     */    private var minScrollInterval:Number = 50;

    /**     *  @private     */    private var rowNameID:Number = 0;

    /**     *  @private     */    private var _editable:Boolean = false;

    /**     *  @private     *  Used to block giving focus to editor on focusIn     */    private var dontEdit:Boolean = false;

    /**     *  @private     */    private var lastUserInteraction:Event;

    /**     *  @private     *  automation delegate access     */    mx_internal var _dropData:Object;

    /**     *  An object that specifies the icons for the items.     *  Each entry in the object has a field name that is the item UID     *  and a value that is an an object with the following format:     *  <pre>     *  {iconID: <i>Class</i>, iconID2: <i>Class</i>}     *  </pre>     *  The <code>iconID</code> field value is the class of the icon for     *  a closed or leaf item and the <code>iconID2</code> is the class     *  of the icon for an open item.     *     *  <p>This property is intended to allow initialization of item icons.     *  Changes to this array after initialization are not detected     *  automatically.     *  Use the <code>setItemIcon()</code> method to change icons dynamically.</p>     *     *  @see #setItemIcon()     *  @default undefined     *       *  @langversion 3.0     *  @playerversion Flash 9     *  @playerversion AIR 1.1     *  @productversion Flex 3     */    public var itemIcons:Object;

    /**     *  @private     */    mx_internal var isOpening:Boolean = false;        /**     *  @private     *  used by opening tween     *  rowIndex is the row below the row that was picked     *  and is the first one that will actually change     */    private var rowIndex:int;

    /**     *  @private     *  Number of rows that are or will be tweened     */    private var rowsTweened:int;

    /**     *  @private     */    private var rowList:Array;        /**     *  @private     */    mx_internal var collectionLength:int;

    /**     *  A hook for accessibility     *       *  @langversion 3.0     *  @playerversion Flash 9     *  @playerversion AIR 1.1     *  @productversion Flex 3     */    mx_internal var wrappedCollection:ICollectionView;

    /**     *  @private     */    mx_internal var collectionThrowsIPE:Boolean;

    /**     *  @private     */    private var haveItemIndices:Boolean;

    /**     *  @private     */    private var lastTreeSeekPending:TreeSeekPending;

 /**  *  @private  */ private var bFinishArrowKeySelection:Boolean = false; private var proposedSelectedItem:Object;