Adobe Flex creating polygon - actionscript-3

Question

How to create a polygon in Adobe flex 3.0

Answer 1

You draw a bunch of lines connecting the points of the polygon.
As a quick example:
function drawPolygon(first, ... rest) {
graphics.moveTo(first.x, first.y);
for(var i = 0; i < rest.length; i++) {
graphics.lineTo(rest[i].x, rest[i].y);
}
graphics.lineTo(first.x, first.y);
}
May be some minor syntax errors, but you get the idea. You'd call it by passing a bunch of Point objects indicating the points of the polygon.

Answer 2

Try this sample
<?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"
xmlns:esri="http://www.esri.com/2008/ags">
<fx:Script>
<![CDATA[
import com.esri.ags.Graphic;
import com.esri.ags.SpatialReference;
import com.esri.ags.Units;
import com.esri.ags.geometry.Geometry;
import com.esri.ags.geometry.MapPoint;
import com.esri.ags.geometry.Polygon;
import com.esri.ags.geometry.Polyline;
import com.esri.ags.utils.GeometryUtil;
import mx.utils.StringUtil;
private const sr:SpatialReference = new SpatialReference(4326);
protected function onCreatePolyline(event:MouseEvent):void
{
addMessage("Create polyline clicked");
var pts:Array = new Array();
for (var i:int; i < 10; i++) // add 10 random points to path
{
var pt:MapPoint = new MapPoint(Math.random()*10000, Math.random()*10000, sr);
pts.push(pt);
}
var pl:Polyline = new Polyline(new Array(pts), sr);
var lengths:Array = GeometryUtil.geodesicLengths(new Array(pl), Units.KILOMETERS);
if (lengths != null && lengths.length > 0)
{
addMessage(StringUtil.substitute("polyline created with length {0} km", lengths[0]));
}
addGraphic(pl);
}
protected function onCreatePolygon(event:MouseEvent):void
{
addMessage("Create polygon clicked");
var pts:Array = new Array();
for (var i:int; i < 10; i++) // add 10 random points to ring
{
var pt:MapPoint = new MapPoint(Math.random()*10000, Math.random()*10000, sr);
pts.push(pt);
}
var pg:Polygon = new Polygon(new Array(pts), sr);
var areas:Array = GeometryUtil.geodesicAreas(new Array(pg), Units.SQUARE_KILOMETERS);
if (areas != null && areas.length > 0)
{
addMessage(StringUtil.substitute("polygon created with area {0} km²", Math.abs(areas[0])));
}
addGraphic(pg);
}
private function addMessage(message:String):void
{
log.text = StringUtil.substitute("> > > {0}\n{1}", message, log.text);
}
private function addGraphic(geometry:Geometry):void
{
var gr:Graphic = new Graphic(geometry);
grLayer.clear();
var grId:String = grLayer.add(gr);
addMessage(StringUtil.substitute("graphic added with id='{0}'", grId));
map.initialExtent = geometry.extent;
map.zoomToInitialExtent();
}
]]>
</fx:Script>
<s:layout>
<s:VerticalLayout gap="10"
paddingBottom="10"
paddingLeft="10"
paddingRight="10"
paddingTop="10"/>
</s:layout>
<s:Button label="Create polyline"
click="onCreatePolyline(event)"/>
<s:Button label="Create polygon"
click="onCreatePolygon(event)"/>
<s:TextArea id="log"
width="100%"
height="100%"/>
<esri:Map id="map"
zoomSliderVisible="false"
minHeight="200"
width="100%">
<esri:GraphicsLayer id="grLayer" />
</esri:Map>
</s:Application>