Flash Stage is Null

Question

这是一个非常简单的AS3项目。这个阶段在主类中不是空的，而是在AppMan类中，这就是我想要访问它的地方。为什么？

这是我的主类，称为StageText.as：

package 
{ 
import flash.display.Sprite; 
import flash.display.StageAlign; 
import flash.display.StageQuality; 
import flash.display.StageScaleMode; 

stage.scaleMode = StageScaleMode.NO_SCALE; //here, the stage is not null. 
stage.align  = StageAlign.TOP_LEFT; 

public class StageText extends Sprite 
{ 
    private var appMan:AppMan = new AppMan(); 

    public function StageText() 
    { 
     appMan.startApp(); 

    } 
} 
} 

然后，在同一文件夹中，我得到了AppMan.as类。

package 
{ 
import flash.events.Event; 
import flash.display.Sprite; 
import flash.text.TextField; 
import flash.display.StageAlign; 
import flash.display.StageQuality; 
import flash.display.StageScaleMode; 

public class AppMan extends Sprite 
{ 
    public var textField:TextField; 

    // Application Width, Height 
    public var appW:Number; 
    public var appH:Number; 

    public function AppMan() 
    { 
     super(); 
    } 

    public function startApp():void { 

     // create textfield 
     textField = new TextField(); 
     textField.wordWrap = true; 
     textField.width = 540; 
     textField.height = 400; 
     textField.text = "Hello World"; 
     addChild(textField); 
        //if I try to run init in response to Event.ADDED_TO_STAGE, it never runs 
     this.addEventListener(Event.ADDED_TO_STAGE, init); 
        //Or, if I run init() without the eventListener, I get a runtime error 
        //indicating that the stage is null 
     //init(); 


    } 

    private function init(e:Event):void { 
    //private function init():void { 

     stage.scaleMode = StageScaleMode.NO_SCALE; 
     stage.align  = StageAlign.TOP_LEFT; 
     stage.quality = StageQuality.HIGH; 
     appW = stage.stageWidth; 
     appH = stage.stageHeight; 
    } 
} 
} 

Answer 1

我在猜测，但是appMan实例是否添加到舞台？

public function StageText() 
{ 
    this.AddChild(appMan); 
    appMan.startApp(); 

}