我正在尝试调用模块的函数（具有两个参数）并为其赋值。我可以看到在跟踪中分配的值，但是在分配给标签时没有显示相同的值。
如果我直接将值分配给标签。它说：
错误：1009：空对象引用
如果我
[Bindable]对该标签使用元标记，它不会显示任何运行时错误，但也不会显示该值。我在互联网上搜索过，发现[Bindable]元标记可以用作 try and catch 博客。
如何将值显示分配给标签？
Main.mxml
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" xmlns:custom="com.custom.*" xmlns:local="*" creationComplete="onload()">
<mx:Script>
<![CDATA[
import modules.AModule;
import mx.events.ModuleEvent;
import mx.containers.VBox;
import mx.containers.TitleWindow;
import mx.controls.TextInput;
import mx.controls.Button;
import mx.containers.HBox;
import mx.controls.Label;
import mx.events.CloseEvent;
import mx.controls.Text;
import com.custom.CustomAlert;
import mx.controls.Alert;
import mx.containers.Canvas;
import mx.events.ItemClickEvent;
import mx.core.UIComponent;
import mx.modules.ModuleManager;
import mx.modules.IModuleInfo;
import mx.containers.Box;
import mx.controls.ProgressBar;
//private var can:Canvas;
public var titlewin:TitleWindow = new TitleWindow();
public var usern:TextInput = new TextInput();
public var passw:TextInput = new TextInput();
public var vb:VBox = new VBox();
public var hb1:HBox = new HBox();
public var hb2:HBox = new HBox();
public var hb3:HBox = new HBox();
public var nc:NetConnection;
public var bt1:Button = new Button();
private var pb:ProgressBar;
private var progressContainer:Box;
private var info:IModuleInfo;
private var module:UIComponent = null;
public var can:Canvas= new Canvas();
public function onload():void
{
var label1:Label= new Label();
var label2:Label= new Label();
label1.text="Username";
label2.text="Password ";
hb1.addChild(label1);
hb1.addChild(usern);
hb2.addChild(label2);
hb2.addChild(passw);
vb.addChild(hb1);
vb.addChild(hb2);
bt1.label="Sign In";
hb3.addChild(vb);
hb3.addChild(bt1);
titlewin.addChild(hb3);
//Title Window creation starts here
titlewin.title="Login";
titlewin.setStyle("paddingLeft",20);
titlewin.setStyle("paddingRight",20);
titlewin.setStyle("paddingTop",20);
titlewin.setStyle("paddingBottom",20);
titlewin.setStyle("borderThicknessBottom",0);
titlewin.setStyle("borderThicknessLeft",0);
titlewin.setStyle("borderThicknessRight",0);
titlewin.setStyle("borderThicknessTop",0);
titlewin.setStyle("cornerRadius",0);
titlewin.setStyle("borderColor","#D20101");
this.addChild(titlewin);
viewStack.enabled=false;
ctbb.enabled=false;
bt1.addEventListener(MouseEvent.CLICK, netconn);
}
private function onclick():void
{
if(usern.text!="")
{
this.removeChild(titlewin);
viewStack.enabled=true;
ctbb.enabled=true;
username.text=usern.text;
}
else
{
Alert.show("Please enter Username");
}
}
private function netconn(event:MouseEvent):void
{
nc = new NetConnection();
nc.connect("rtmp://localhost/loginhere",usern.text);
nc.addEventListener(NetStatusEvent.NET_STATUS, onstatushandler);
}
private function onstatushandler(event:NetStatusEvent):void
{
if(event.info.code=="NetConnection.Connect.Success")
{
status.text="Connected";
onclick();
}
if(event.info.code=="NetConnection.Connect.Rejected")
{
status.text="Rejected";
}
if(event.info.code=="NetConnection.Connect.Failed")
{
status.text="Failed";
}
}
private function JoinClick(event:MouseEvent):void{
if(viewStack.numChildren==3)
{
Alert.show("You Cant Add More Button","Alert");
}
if(viewStack.numChildren<3)
{
if(viewStack.numChildren<2)
{
can.label="Button2";
var button1:CustomButton= new CustomButton();
button1.label="Leave Table";
button1.x=300;
button1.y=200;
var txt:Text = new Text();
txt.text=can.label;
txt.x=50;
txt.y=50;
button1.addEventListener(MouseEvent.CLICK,remove2);
can.addChild(button1);
can.addChild(txt);
loadmodule();
}
else
{
can.label="Button3";
var button2:CustomButton= new CustomButton();
button2.label="Leave Table";
button2.x=300;
button2.y=200;
button2.addEventListener(MouseEvent.CLICK,remove3);
can.addChild(button2);
var txt1:Text = new Text();
txt1.text=can.label;
txt1.x=50;
txt1.y=50;
can.addChild(txt1);
}
can.setStyle("backgroundColor","0x5EA5BA");
viewStack.addChild(can);
if(viewStack.numChildren>2)
{
viewStack.selectedIndex=2;
}
else
{
viewStack.selectedIndex=1;
}
}
}
private function remove2(event:MouseEvent):void{
Alert.show("Do you want to Leave Table?","Confirmation",Alert.YES|Alert.NO,this,closeAlert2);
}
private function closeAlert2(event:CloseEvent):void{
if(event.detail==Alert.YES)
{
viewStack.removeChildAt(1);
}
}
private function remove3(event:MouseEvent):void{
if(viewStack.numChildren>2)
{
Alert.show("Do You want to leave Table?","Confirmation",Alert.YES|Alert.NO,this,closeAlert3);
}
else
{
Alert.show("Do you want to Leave Table?","Confirmation",Alert.YES|Alert.NO,this,closeAlert1);
}
}
private function closeAlert1(event:CloseEvent):void{
if(event.detail==Alert.YES)
{
viewStack.removeChildAt(1);
}
}
private function closeAlert3(event:CloseEvent):void{
if(event.detail==Alert.YES)
{
viewStack.removeChildAt(2);
}
}
private function loadmodule():void
{
pb = new ProgressBar();
pb.labelPlacement = "center";
pb.label = "Loading %3 %";
progressContainer = new Box();
progressContainer.percentWidth = 100;
progressContainer.percentHeight = 100;
progressContainer.setStyle("horizontalAlign", "center");
progressContainer.setStyle("verticalAlign", "middle");
progressContainer.addChild(pb);
can.addChild(progressContainer);
var moduleUrl:String="../bin-debug/modules/useModule.swf";
info=ModuleManager.getModule(moduleUrl);
if(info!=null)
{
info.addEventListener(ModuleEvent.READY, modEventHandler);
info.addEventListener(ModuleEvent.ERROR,modErrorHandler);
info.load();
}
}
private function modEventHandler(e:ModuleEvent):void
{
info.removeEventListener(ModuleEvent.READY, modEventHandler);
info.removeEventListener(ModuleEvent.ERROR, modErrorHandler);
can.removeAllChildren();
if(module==null)
{
module = info.factory.create() as UIComponent;
if(module!=null)
{
module.x=0;
module.y=0;
module.percentWidth=100;
module.percentHeight=100;
can.addChild(module);
if(module is AModule)
{
}
}
}
}
private function modErrorHandler(event:ModuleEvent):void {
//cleanup and display an error alert
info.removeEventListener(ModuleEvent.READY, modEventHandler);
info.removeEventListener(ModuleEvent.ERROR, modErrorHandler);
info = null;
Alert.show(event.toString(), "Error Loading Module");
unloadModule();
}
private function unloadModule():void
{
can.removeAllChildren();
if (module != null && info != null) {
info.addEventListener(ModuleEvent.UNLOAD, unloadEventHandler);
info.unload();
}
}
private function unloadEventHandler(e:ModuleEvent):void
{
info.removeEventListener(ModuleEvent.UNLOAD, unloadEventHandler);
module = null;
info = null;
}
]]>
</mx:Script>
<mx:Canvas width="700" height="400" x="166" y="32">
<mx:ViewStack id="viewStack" width="100%" height="100%">
<mx:Canvas label="Button1" backgroundColor="#5EA5BA" visible="true" id="can1" >
<local:CustomButton label="Join" click="JoinClick(event)" x="536" y="222"/>
<mx:Label x="304" y="120" text="Label" id="username"/>
<mx:Label x="304" y="55" text="Label" id="status"/>
</mx:Canvas>
</mx:ViewStack>
</mx:Canvas>
<custom:CustomControlBar x="166" y="423" id="ctbb">
<custom:CustomToggleButtonBar dataProvider="viewStack"/>
</custom:CustomControlBar>
</mx:Application>
使用模块.mxml
<?xml version="1.0" encoding="utf-8"?>
<mx:Module xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" width="508" height="218" implements="modules.AModule" backgroundColor="#F00F0F" creationComplete="addlabel();">
<mx:Script>
<![CDATA[
import mx.core.Application;
public var logsin:loginhere = new loginhere();
public function addlabel():void
{
lb1.text=logsin.username.text;
txt3.text=logsin.username.text;
trace(txt3.text);
trace(lb1.text);
}
]]>
</mx:Script>
<mx:TextInput id="txt3" x="30.5" y="10" width="79"/>
<mx:Label id="lb1" x="31.5" y="40" width="78" text="Will it Change?"/>
</mx:Module>
AModule.as（它的一个接口）
package modules
{
import flash.events.IEventDispatcher;
public interface AModule extends IEventDispatcher
{
function addlabel():void;
}
}