Question

我试图将属性和函数声明为特定的js类。但是当我尝试在函数内调用函数时（即使在声明后调用）它会抛出异常

未捕获TypeError：对象[object Object]没有方法'addButtonEventListeners

我的代码列出：SplashScene.js

var anim1, background;
var SplashScene;

function SplashScreen(SceneContainer)
{
this.name = "SplashScreen";
this.loadScreen = function()
{

    background = new createjs.Shape();
    background.graphics.beginBitmapFill(loader.getResult("gameLoopSplash")).drawRect(0,0,w,h);
    SplashScene = new createjs.Container();

    anim1 = new createjs.Sprite(buttonData, "playIdle");
    anim1.framerate = 30;
    anim1.x = 260;
    anim1.y = 22;
    SplashScene.alpha = 0;

    SplashScene.addChild(background);
    SplashScene.addChild(anim1);
}

this.addButtonEventListeners =  function()
{
    console.log("addButtonEventListeners   SplashScreen" );
}

this.menuIn = function()
{
    console.log("menuIn   SplashScreen" );
    stage.addChild(SplashScene);
    var tween = createjs.Tween.get(SplashScene).to({y : 0, x : 0, alpha : 1}, 5000).call(this.menuInCompleted);
    var splashTimer = window.setTimeout(function(){menuOut("MainScreen", false)},15000);

}

this.menuInCompleted = function()
{
    console.log("menuInCompleted   SplashScreen" );
    this.addButtonEventListeners();
}
}

有人能告诉我怎么办？

Answer 1

问题是this回调中的上下文（setTimeout）是window，而不是您的对象。

您可以更改

var splashTimer = window.setTimeout(function(){menuOut("MainScreen", false)},15000);

到

var splashTimer = window.setTimeout(
     (function(){menuOut("MainScreen", false)}).bind(this)
,15000);

你还必须在绑定menuIn（对某个事件？）的地方做同样的事情。

Answer 2

您的问题是this，它指向当前上下文（在运行时）而不是您的对象。只需在SplashScreen中添加一个变量，如：

var self=this; //keeping the context of SplashScreen

然后按如下方式调用它：

this.menuInCompleted = function()
{
    console.log("menuInCompleted   SplashScreen" );
    self.addButtonEventListeners ();
}

在javascript类函数中调用函数？

2 个答案: