flex tree自动显示横向滚动条实现代码

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我是靠谱客的博主幸福战斗机，最近开发中收集的这篇文章主要介绍flex tree自动显示横向滚动条实现代码，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

复制代码代码如下:

 
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); 
} 
} 
} 