Question

我开始制作一个flash flash em-up游戏教程，我完成了它Asgamer Shoot em upp Game
现在我开始创建一个新的.fla，它是主菜单，我有一个播放按钮，所以当我按下它将加载.swf（游戏swf），但当我按下按钮时，我得到以下错误。

TypeError: Error #1009: Cannot access a property or method of a null object reference.
 -at com.senocular.utils::KeyObject/construct()
 -at com.senocular.utils::KeyObject()
 -at com.actionscript.Ergasia::Ship()
 -at com.actionscript.Ergasia::Engine()





public function Engine() : void {
    if(stage) {
        initialize();
    } else {
        addEventListener(Event.ADDED_TO_STAGE,initialize);
    }
} 

    private function initialize(e:Event = null):void {
        removeEventListener(Event.ADDED_TO_STAGE,initialize);
        //  here goes the code that's currently in Engine constructor
    }

编辑：感谢Viper解决这个问题！

Answer 1

将Engine构造函数更改为以下内容：

public function Engine() {
    if(stage) {
        initialize();
        } else  addEventListener(Event.ADDED_TO_STAGE,initialize);
    } 

private function initialize(e:Event = null):void {
    removeEventListener(Event.ADDED_TO_STAGE,initialize);
    //  here goes the code that was in Engine constructor
    trace(stage);
        ourShip = new Ship(stage);
        stage.addChild(ourShip);
        ourShip.x = stage.stageWidth / 2;
        ourShip.y = stage.stageHeight / 2;
        ourShip.addEventListener("hit", shipHit, false, 0, true);
        stage.addChild(ourShip);
        scoreHUD = new ScoreHUD(stage);
        stage.addChild(scoreHUD);

        for (var i:int = 0; i < numCloud; i++)
        {
            stage.addChildAt(new Cloud(stage), stage.getChildIndex(ourShip));

        }
        for (var b:int = 0; b < numStar; b++)
        {
            stage.addChildAt(new Star(stage), stage.getChildIndex(ourShip));
        }

        addEventListener(Event.ENTER_FRAME, loop, false, 0, true);
}

主要问题是，Engine类的编写假设stage已经可以访问，但是当您加载SWF时，其stage为空，而未添加该SWF到了舞台。为了避免这种情况，常见的做法是使用Event.ADDED_TO_STAGE侦听器，并开始将代码放在那里而不是构造函数。

TypeError：错误＃1009 Actionscript 3加载外部swf

1 个答案: