对象找不到方法

Question

我试图做一个状态机，但它不工作。我有这个代码至今：

function makeStateMachine() { 
    this.stateConstructors = new Object(); 
    this.currState = { 
     update : function(e) { 
      // Nothing to do here 
     }, 
     exit : function() { 
      // Nothing to declare 
     } 
    }; 
    this.nextState = null; 

    var that = this; 

    this.update = new function(e) { 
     that.currState.update(e); 

     that.changeState(); 
    }; 

    this.setNextState = new function(targetState) { 
     that.nextState = targetState; 
    }; 

    this.addState = new function(constructor, stateName) { 
     that.stateConstructors[stateName] = constructor; 
    }; 

    this.changeState = new function() { 
     if (that.nextState != null) { 
      that.currState.exit(); 
      that.currState = new that.stateConstructors[that.nextState](); 

      that.nextState = null; 
     } 
    }; 
} 

当我尝试运行它萤火显示此错误：“类型错误：that.changeState不是一个函数”在更新功能就行了。当我取消注释changeState（）行时，它开始抱怨EaselJS库不正确（我知道这是正确的，因为它适用于我的其他项目）。有人可以帮助我吗？这可能很简单（就像往常一样），但我不能发现错误。如果你们喜欢，我可以发布其余的代码，但我认为它不相关。

在此先感谢！

Answer 1

你应该把这些功能放在原型中。你也不应该使用= new function(...;只需使用= function(...即可。最后，你不需要that。试试这段代码：

function makeStateMachine() { 
    this.stateConstructors = {}; 
    this.currState = { 
     update : function(e) { 
      // Nothing to do here 
     }, 
     exit : function() { 
      // Nothing to declare 
     } 
    }; 
    this.nextState = null; 
} 

makeStateMachine.prototype.update = function(e) { 
    this.currState.update(e); 
    this.changeState(); 
}; 

makeStateMachine.prototype.setNextState = function(targetState) { 
    this.nextState = targetState; 
}; 

makeStateMachine.prototype.addState = function(constructor, stateName) { 
    this.stateConstructors[stateName] = constructor; 
}; 

makeStateMachine.prototype.changeState = function() { 
    if (this.nextState != null) { 
     this.currState.exit(); 
     this.currState = new this.stateConstructors[this.nextState](); 
     this.nextState = null; 
    } 
};