Count the number of items in a collection between the selected item in a ComboBox control and the end of the collection, and then returns the cursor to the initial location
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<!-- dpcontrols\UseBookmarks.mxml -->
<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" initialize="run();">
<s:layout>
<s:VerticalLayout />
</s:layout>
<fx:Script>
import mx.collections.*;
private var myCursor:IViewCursor;
// Initialize variables.
public function run():void {
// Initialize the cursor.
myCursor=myAC.createCursor();
// The findFirst() method, used in
// countFromSelection() requires a
// sorted view.
var sort:Sort = new Sort();
sort.fields=[new SortField("label")];
myAC.sort=sort;
//You must refresh the view to apply the sort.
myAC.refresh();
}
// Count the items following the current
// cursor location.
public function countLast(theCursor:IViewCursor):int {
var counter:int=0;
// Set a bookmark at the current cursor location.
var mark:CursorBookmark=theCursor.bookmark;
// Move the cursor to the end of the Array.
// The moveNext() method returns false when the cursor
// is after the last item.
while (theCursor.moveNext()) {
counter++;
}
// Return the cursor to the initial location.
theCursor.seek(mark);
return counter;
}
// Function triggered by ComboBox change event.
// Calls the countLast() function to count the
// number of items to the end of the collection.
public function countFromSelection():void {
myCursor.findFirst(myCB.selectedItem);
var count:int = countLast(myCursor);
ta1.text += myCursor.current.label + " is " + count + " from the last item.\n";
}
</fx:Script>
<fx:Declarations>
<!-- The data provider, an ArrayCollection with an array of objects. -->
<mx:ArrayCollection id="myAC">
<fx:Object label="MA" data="Boston" />
<fx:Object label="ME" data="Augusta" />
<fx:Object label="MI" data="Lansing" />
<fx:Object label="MN" data="Saint Paul" />
<fx:Object label="MO" data="Jefferson City" />
<fx:Object label="MS" data="Jackson" />
<fx:Object label="MT" data="Helena" />
</mx:ArrayCollection>
</fx:Declarations>
<s:ComboBox id="myCB" dataProvider="{myAC}" change="countFromSelection();" />
<s:TextArea id="ta1" height="200" width="175" />
</s:Application>
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