通过每个组件实例进行递归迭代答案

【问题标题】：Recursive iteration through every component instance通过每个组件实例进行递归迭代
【发布时间】：2009-11-17 19:48:17
【问题描述】：

我的 flex 应用程序中有各种自定义组件实例。我想递归地遍历它们并获取它们的实例 ID。递归部分对我来说非常重要。有人能告诉我最好的方法是什么吗？我试过这样做，但它没有递归：

for each (var myItem:* in this.MasterContainer.childDescriptors)
{
   trace(myItem.id);
}

【问题讨论】：

标签： apache-flex actionscript-3 mxml

【解决方案1】：

这样就可以了：

private function findControlsRecursive(current:DisplayObjectContainer, controls:ArrayCollection):void
{
    for(var idx:int = 0; idx < current.numChildren; idx++)
    {
        var child:DisplayObject = current.getChildAt(idx);
        controls.addItem(child.name);
        var childContainer:DisplayObjectContainer = child as DisplayObjectContainer;
        if(childContainer)
        {
            findControlsRecursive(childContainer, controls);
        }
    } 
}

public function findControls():ArrayCollection
{
    var controls:ArrayCollection = new ArrayCollection();
    findControlsRecursive(Application.application as DisplayObjectContainer, controls);
    return controls;
}

【讨论】：

【解决方案2】：

我用它来迭代几种方法中的所有组件，其中一些方法在累加器acc 中建立结果（例如，写入一个字符串，记录所有的计数，等等）。当useRaw 为true 时，迭代包括组件chrome。

    /**
     * Descends through subcomponents applying function
     */
    public static function visitComponent(component:Object, fn:Function, useRaw:Boolean = false, acc:Object = null):Object {
        var newAcc:Object = fn.call(null, component, acc);

        if (component is mx.core.Container) {
            var kids:mx.core.Container = mx.core.Container(component);
            var childList:IChildList;
            if (useRaw) {
                childList = kids.rawChildren;
            } else {
                childList = kids;
            }
            for (var i:int = 0; i < childList.numChildren; ++i) {
                visitComponent(childList.getChildAt(i), fn, useRaw, newAcc);
            }
        } else if (component is DisplayObjectContainer) {
            var displayObjContainer:DisplayObjectContainer = component as DisplayObjectContainer;
            for (var j:int = 0; j < displayObjContainer.numChildren; ++j) {
                visitComponent(displayObjContainer.getChildAt(j), fn, useRaw, newAcc);
            }               
        }
        return newAcc;
    }

    /**
     * Randomly resets backgroundColor of subcomponents
     */
    public static function colorizeComponent(component:Object):void {
        var fn:Function = function(c:Object, acc:Object):Object {
            if (c is UIComponent) {
                (c as UIComponent).setStyle("backgroundColor", Math.random() * uint.MAX_VALUE);
                (c as UIComponent).setStyle("backgroundAlpha", 0.2);
            }
            return null;
        }

        visitComponent(component, fn);
    }

【讨论】：

【解决方案3】：

Michael Brewer-Davis 的函数比这个例子更全面（处理 rawchildren、非 flex 组件等），但不需要递归遍历树：

function toEveryComponentDo(f:Function):void
{
    var component:UIComponent = Application.application;
    var components:Array = component.getChildren();
    f(component);

    while (components.length > 0)
    {
        var childComponents:Array = [];

        for each (component in components)
        {
            f(component);
            if (component is Container)
            {
                childComponents = childComponents.append(Container(component).getChildren());
            }
        }

        components = childComponents;
    }
}

【讨论】：

我喜欢你的函数，但它似乎有一些语法错误。 UIComponent 没有 .getChildren() 函数。