package com.anydata.consumer.components { import flash.events.Event; import mx.controls.Tree; import mx.core.ScrollPolicy; import mx.core.mx_internal; /** * 自动显示横向滚动条 */ public class AutoSizeTree extends Tree { public function AutoSizeTree() { super(); horizontalScrollPolicy=ScrollPolicy.AUTO; } override public function get maxHorizontalScrollPosition():Number { if (isNaN(mx_internal::_maxHorizontalScrollPosition)) return 0; return mx_internal::_maxHorizontalScrollPosition; } override public function set maxHorizontalScrollPosition(value:Number):void { mx_internal::_maxHorizontalScrollPosition=value; dispatchEvent(new Event("maxHorizontalScrollPositionChanged")); scrollAreaChanged=true; invalidateDisplayList(); } override protected function updateDisplayList(unscaledWidth:Number, unscaledHeight:Number):void { var diffWidth:Number=measureWidthOfItems(0, 0) - (unscaledWidth - viewMetrics.left - viewMetrics.right); var indentation:Number=getStyle("indentation"); if (diffWidth <= 0) maxHorizontalScrollPosition=NaN; else maxHorizontalScrollPosition=diffWidth + indentation; super.updateDisplayList(unscaledWidth, unscaledHeight); } } }