<mx:Tree/> 只会自动显示垂直滚动条而不会自动显示水平滚动条,貌似是因为没有对
maxHorizontalScrollPosition属性进行动态的处理,一下重写tree组件,可以自动显示水平滚动条。
- package com.common.tree {
- 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
- * @author chensong
- *
- */
- 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);
- }
- }
- }