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Flex Viewer 开发教程（4）Widget与Map交互

发布时间：2020-12-15 04:10:05 所属栏目：百科 来源：网络整理
导读：Widget与Map之间的交互是最常见的一种交互，BaseWidget不仅定义了Map实例对象，而且封装了与Map进行交互的方法。BaseWidget良好封装使Widget与Map交互非常简单。 4.1?交互方式1：map实例 在BaseWidget中，有如下代码： /** ? * Current active map that the

Widget与Map之间的交互是最常见的一种交互，BaseWidget不仅定义了Map实例对象，而且封装了与Map进行交互的方法。BaseWidget良好封装使Widget与Map交互非常简单。

4.1?交互方式1：map实例

在BaseWidget中，有如下代码：

/**

?* Current active map that the container shows.

?* The WidgetManager will set its value when a widget is initialized.

?*/

private?var?_map:Map;

[Bindable]

/**

?* Set a map object reference. Used by WidgetManager to pass in the current

* map.

* @param value the map reference object.

?*/

public?function?get?map():Map{

????return?_map;

}

public?function?set?map(value:Map):void{

????_map = value;

}

通过注释可知，Widget在初始化的时候，WidgetManager会将当前的map实例注入Widget。所以，一旦Widget初始化完成，就有一个map实例可供使用。

下面我们实现一个HelloMapWidget，来说明在Widget如何使用map实例，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<viewer:BaseWidget?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:viewer="com.esri.viewer.*"

?????????????????layout="absolute"?width="400"?height="300"

?????????????????widgetConfigLoaded="init()">

????<fx:Script>

???????<![CDATA[

???????????import?com.esri.ags.geometry.MapPoint;

???????????import?mx.controls.Label;

?

???????????private?var?helloContent:String;

?

???????????private?function?init():void{

??????????????if?(configXML){

??????????????????helloContent=String(configXML.hellocontent);

??????????????}

???????????}

?

???????????private?function?sayHiToMap():void{

??????????????var?center:MapPoint=map.extent.center;

??????????????var?message:Label=new?Label();

??????????????message.text=helloContent;

??????????????map.infoWindowContent=message;

??????????????map.infoWindow.show(center);

???????????}

???????]]>

????</fx:Script>

????<viewer:WidgetTemplate>

???????<s:HGroup?height="100%"?width="100%"?horizontalAlign="center"

????????????????verticalAlign="middle">

???????????<s:Button?label="Say Hi to Map"?click="sayHiToMap()"/>

???????</s:HGroup>

????</viewer:WidgetTemplate>

</viewer:BaseWidget>

HelloMapWidget实现的功能是，单击“Say Hi to Map”按钮，在地图当前视图范围的中心点显示infoWindow，infoWindow显示的内容是配置文件中的字符。运行结果如下图所示：

?

有了map实例，在Widget就可以做任何与Map相关的事情，比如控制Map图层、获得Map的各种信息等等，具体可参考Flex Viewer中的NavigationWidget、MapSwitcherWidget等。

4.2?交互方式2：BaseWidget封装的方法

除了map实例，Widget可以通过BaseWidget中封装的方法与Map进行交互（实际上是与MapManager的交互），见如下代码：

/**

?* Show information window (infoWindow) based on infoData from widget.

?*/

public?function?showInfoWindow(infoData:Object):void{

?????ViewerContainer.dispatchEvent(newAppEvent(AppEvent.SHOW_INFOWINDOW,infoData));

}

/**

?* Set map action from widget.

?*/

public?function?setMapAction(action:String,status:String,symbol:Symbol,callback:Function):void{

????var?data:Object ={

????????????tool: action,

????????????status: status,

????????????symbol: symbol,

????????????handler: callback};

????ViewerContainer.dispatchEvent(new?AppEvent(AppEvent.SET_MAP_ACTION,data));

}

/**

?* Set map navigation mode,such a pan,zoomin,etc.

?* <p>The navigation methods supported are:</p>

?* <listing>

?* pan??????????(Navigation.PAN)

?* zoomin???????(Navigation.ZOOM_IN)

?* zoomout??????(Navigation.ZOOM_OUT)

?* zoomfull?????(ViewerContainer.NAVIGATION_ZOOM_FULL)

?* zoomprevious (ViewerContainer.NAVIGATION_ZOOM_PREVIOUS)

?* zoomnext?????(ViewerContainer.NAVIGATION_ZOOM_NEXT)

?* </listing>

?*/

public?function?setMapNavigation(navMethod:String,status:String):void{

????var?data:Object ={

????????????tool: navMethod,

????????????status: status};

????ViewerContainer.dispatchEvent(newAppEvent(AppEvent.SET_MAP_NAVIGATION,data));

}

u??showInfoWindow()

弹出窗口并显示信息。

u??setMapAction()

设置画图操作。

u??setMapNavigation()

设置导航操作。

由于是与MapManager交互，上述三个方法中只是派发了相应的事件，这些事件由MapManager监听、捕捉和响应，在MapManager中有如下代码说明对上述三个方法派发的事件进行了监听：

ViewerContainer.addEventListener(AppEvent.SET_MAP_NAVIGATION,changeNavigationbyMenu);

ViewerContainer.addEventListener(AppEvent.SET_MAP_ACTION,enableMapAction);

ViewerContainer.addEventListener(AppEvent.SHOW_INFOWINDOW,widgetShowInfo);

下面实现HelloMapManagerWidget，演示如何使用上述三个方法，代码如下：

<?xml version="1.0" encoding="utf-8"?>

<viewer:BaseWidget?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:viewer="com.esri.viewer.*"

?????????????????widgetConfigLoaded="init()">

????<fx:Script>

???????<![CDATA[

???????????import?com.esri.ags.events.DrawEvent;

???????????import?com.esri.ags.layers.GraphicsLayer;

???????????import?com.esri.ags.tools.DrawTool;

???????????import?com.esri.ags.tools.NavigationTool;

???????????import?com.esri.viewer.ViewerContainer;

?

???????????private?var?helloContent:String;

???????????private?var?graphicsLayer:GraphicsLayer;

?

???????????private?function?init():void{

??????????????if?(configXML){

??????????????????helloContent=String(configXML.hellocontent);

??????????????}

??????????????graphicsLayer=new?GraphicsLayer();

??????????????map.addLayer(graphicsLayer);①

???????????}

?

???????????private?function?sayHiToMapManager():void{②

var?infoData:Object={content: helloContent,point: map.extent.center};

??????????????this.showInfoWindow(infoData);

???????????}

?

???????????private?function?activateMapNavigation(tool:String):void{③

??????????????this.setMapNavigation(tool,?null);

???????????}

?

???????????private?function?draw(shape:String):void{④

??????????????this.setMapAction(shape,?null,drawEnd);

???????????}

???????????private?function?drawEnd(event:DrawEvent):void{⑤

??????????????graphicsLayer.add(event.graphic);

???????????}

???????]]>

????</fx:Script>

????<viewer:WidgetTemplate?width="680"?height="200">

???????<s:VGroup?width="100%"?height="100%"

????????????????verticalAlign="middle"?horizontalAlign="center">

???????????<s:HGroup?width="100%">

??????????????<s:Button?label="Say Hi to MapManager"

???????????????????????click="sayHiToMapManager()"/>

???????????</s:HGroup>

???????????<s:HGroup?width="100%">⑥

??????????????<s:Button?label="Zoom In"

??????????????click="activateMapNavigation(NavigationTool.ZOOM_IN)"/>

??????????????<s:Button?label="Zoom Out"

??????????????click="activateMapNavigation(NavigationTool.ZOOM_OUT)"/>

??????????????<s:Button?label="Pan"

??????????????click="activateMapNavigation(NavigationTool.PAN)"/>

?????????????<s:Button?label="Previous View" click="activateMapNavigation(ViewerContainer.NAVIGATION_ZOOM_PREVIOUS)"/>

?????????????<s:Button?label="Next View"?click="activateMapNavigation(ViewerContainer.NAVIGATION_ZOOM_NEXT)"/>

?????????????<s:Button?label="Full Extent"??????????????????????click="activateMapNavigation(ViewerContainer.NAVIGATION_ZOOM_FULL)"/>

???????????</s:HGroup>

???????????<s:HGroup?width="100%">⑦

??????????????<s:Button?label="Point"

???????????????????????click="draw(DrawTool.MAPPOINT)"/>

??????????????<s:Button?label="Polyline"

???????????????????????click="draw(DrawTool.POLYLINE)"/>

??????????????<s:Button?label="Polygon"

???????????????????????click="draw(DrawTool.POLYGON)"/>

??????????????<s:Button?label="Extent"

???????????????????????click="draw(DrawTool.EXTENT)"/>

??????????????<s:Button?label="Circle"

???????????????????????click="draw(DrawTool.CIRCLE)"/>

??????????????<s:Button?label="Freehand Polyline"

???????????????????????click="draw(DrawTool.FREEHAND_POLYLINE)"/>

??????????????<s:Button?label="Freehand Polygon"

???????????????????????click="draw(DrawTool.FREEHAND_POLYGON)"/>

???????????</s:HGroup>

???????</s:VGroup>

????</viewer:WidgetTemplate>

</viewer:BaseWidget>

①????map添加GraphicsLayer实例，用于显示画图结果；

②????构造infoData对象，调用showInfoWindow()方法，单击“Say Hi to MapManager”按钮，将显示下图所示信息框（InfoPupup.mxml和defaults.css已作出相应调整，见源代码）：

③?????调用setMapNavigation()方法，设置当前地图导航操作，Zoom In的效果如下图所示：

?

④????调用setMapAction()方法，设置地图画图操作，如下图所示：

?

⑤????响应画图事件的方法，在此方法中将画图事件中的graphic添加到graphicsLayer中；

⑥????设置地图导航操作的按钮，click事件中调用activateMapNavigation()方法；

⑦????设置画图操作的按钮，click事件中调用draw()方法。

（编辑：李大同）

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