Question

我正在尝试根据另一个XMLListCollection的属性对XMLListCollection进行排序，但我没有取得多大成功。

我想将食物集合按照食物的顺序排序 - 它存储在另一个XMLListcollection中。

<?xml version="1.0" encoding="utf-8"?>
<s:Application 
xmlns:fx="http://ns.adobe.com/mxml/2009" 
xmlns:s="library://ns.adobe.com/flex/spark" 
xmlns:mx="library://ns.adobe.com/flex/mx" 
minWidth="955" minHeight="600">
<fx:Declarations>
    <fx:XML xmlns="" id="_foods">
        <data>
            <node label="Apple" id="A"/>
            <node label="Banana" id="B"/>
            <node label="Carrot" id="C"/>
            <node label="Dandelion" id="D"/>
        </data>
    </fx:XML>
    <fx:XML xmlns="" id="_orders">
        <data>
            <order  id="C"/>
            <order  id="A"/>
            <order  id="D"/>
            <order  id="B"/>
        </data>
    </fx:XML>
    <s:XMLListCollection id="_orderList" source=" {_orders.children()}"/>
    <s:XMLListCollection id="_foodCollection"   source="{_foods.children()}" sort="{_foodSort}"/>
    <s:Sort id="_foodSort" compareFunction="sortFruits"/>
</fx:Declarations>
<fx:Script>
    <![CDATA[

        protected function sortFruits(a:Object, b:Object, fields:Array = null):int
        {
         var _currentItem:XML = XML(a);
         var _currentOrderIndex:int= getNodeIndexByAttribute(_orderList,'id',_currentItem.@id);
            var _currentFruitIndex:int= getNodeIndexByAttribute(_foodCollection,'id',_currentItem.@id)

            if(_currentFruitIndex > _currentOrderIndex) {_returnData =1;}
            else 
            if(_currentFruitIndex < _currentOrderIndex) { _returnData =-1;}
            else {_returnData = 0}

            var _returnData:int = 0
                return _returnData
        }

        public function getNodeIndexByAttribute(theCollection:XMLListCollection,theAttributeName:String, theAttributeValue:String):int { 
            //THIS IS RETURNS THE INDEX OF A CHILD NODE BASED UPON AN ATTRIBUTE THAT IS PASSED IN - GENERIC FUNCTION
            var _returnData:int 

            for (var i:int = 0; i < theCollection.length; i++) 
            {
                var _currentItem:XML = theCollection.getItemAt(i) as XML
                if (_currentItem.attribute(theAttributeName) == theAttributeValue)  { _returnData = i;
        break;
                }

            }


            return _returnData;
        } 
    ]]>
</fx:Script>
<s:List width="100%" height="100%" labelField="@label" dataProvider="{_foodCollection}"/>
</s:Application>

就我所见，我似乎正在尽一切努力，但我必须做错事，因为它不起作用！我认为这可能与我如何实现比较功能有关。

对此有任何帮助将不胜感激！ ;）

Answer 1

通过定义 sort 函数，默认情况下不会对XMLListCollection进行排序。您需要在某个时刻刷新（）集合，这可以在您加载视图或按需时自动完成。我添加了一个按钮来说明这一点。

如果你测试我添加的这个按钮，它应该可以工作。另外，我已经用mx替换了s：sort，因为我使用的是较旧的Flex Framework，所以请随时再修改它。

<?xml version="1.0" encoding="utf-8"?>
<s:Application
    xmlns:fx="http://ns.adobe.com/mxml/2009"
    xmlns:s="library://ns.adobe.com/flex/spark"
    xmlns:mx="library://ns.adobe.com/flex/mx"
    >

<s:layout>
    <s:VerticalLayout />
</s:layout>

<fx:Declarations>

    <mx:Sort id="sort" compareFunction="sortFruits" />

    <fx:XML xmlns="" id="_foods">
        <data>
            <node label="Apple" id="A"/>
            <node label="Banana" id="B"/>
            <node label="Carrot" id="C"/>
            <node label="Dandelion" id="D"/>
        </data>
    </fx:XML>
    <fx:XML xmlns="" id="_orders">
        <data>
            <order id="C"/>
            <order id="A"/>
            <order id="D"/>
            <order id="B"/>
        </data>
    </fx:XML>
    <s:XMLListCollection id="_orderList" source=" {_orders.children()}"/>
    <s:XMLListCollection id="_foodCollection" source="{_foods.children()}" sort="{sort}"/>
</fx:Declarations>


<fx:Script>
<![CDATA[
    protected function sortFruits(a:Object, b:Object, fields:Array = null):int {
        var _currentItem:XML = XML(a);
        var _currentOrderIndex:int = getNodeIndexByAttribute(_orderList, 'id', _currentItem.@id);
        var _currentFruitIndex:int = getNodeIndexByAttribute(_foodCollection, 'id', _currentItem.@id)

        if (_currentFruitIndex > _currentOrderIndex) {
            _returnData = 1;
        }
        else if (_currentFruitIndex < _currentOrderIndex) {
            _returnData = -1;
        }
        else {
            _returnData = 0
        }

        var _returnData:int = 0
        return _returnData
    }

    public function getNodeIndexByAttribute(theCollection:XMLListCollection, theAttributeName:String, theAttributeValue:String):int {
        //THIS IS RETURNS THE INDEX OF A CHILD NODE BASED UPON AN ATTRIBUTE THAT IS PASSED IN - GENERIC FUNCTION
        var _returnData:int

        for (var i:int = 0; i < theCollection.length; i++) {
            var _currentItem:XML = theCollection.getItemAt(i) as XML
            if (_currentItem.attribute(theAttributeName) == theAttributeValue) {
                _returnData = i;
                break;
            }

        }


        return _returnData;
    }
    ]]>
</fx:Script>
    <s:List width="100%" labelField="@label" dataProvider="{_foodCollection}"/>
    <s:Button label="Sort me" click="_foodCollection.refresh()" />
</s:Application>

使用compare函数对XMLLIstCollection进行排序

1 个答案: