Question

我真的很难想出一个标题，但基本上我正在使用html5画布上的游戏，并且在与ai对战时有一个名为player的子类aiPlayer。更新玩家的代码如下：

  var entitiesCount = this.entities.length;
  for (var i = 0; i < entitiesCount; i++) {
      var entity = this.entities[i];
      entity.update();
      if (entity instanceof special && entity.x > WIDTH || entity.x + 200 < 0) {
          this.entities.splice(i, 1);
          entitiesCount--;
      }
  }

但是，aiPlayer永远不会使用aiPlayer更新功能进行更新。我已经打印出每个实体的构造函数，并且有一个Player和一个aiPlayer。但是，当打印出他们正在调用的方法时，他们都调用了Player更新。有谁知道为什么会这样做？此外，如果有帮助，aiPlayer更新如下：

aiPlayer.prototype.update = function() {
    if((this.game.timer.gameTime % this.moveTime) > (this.moveTime * 0.9)) {        
        this.chooseMove();
    }
    Player.prototype.update.call(this);
};

ai构造函数看起来像：

function aiPlayer (game, character, x, y, health) {
    Player.call(this, game, character, x, y, health, PLAYER2_CONTROLS, "left");
    aiPlayer.prototype = new Player(this.game, this.character, this.x, this.y,
                                this.health, this.control, this.facing);
    aiPlayer.prototype.constructor = aiPlayer;
    this.controls = PLAYER2_CONTROLS;
    this.attackLength = 50;
    this.fleeLength = 70;
    this.moveTime = 1;
    this.prevControl = "idle";
}

Answer 1

function aiPlayer (game, character, x, y, health) {
    Player.call(this, game, character, x, y, health, PLAYER2_CONTROLS, "left");
    aiPlayer.prototype = new Player(this.game, this.character, this.x, this.y,this.health, this.control, this.facing);
    aiPlayer.prototype.constructor = aiPlayer;
    this.controls = PLAYER2_CONTROLS;
    this.attackLength = 50;
    this.fleeLength = 70;
    this.moveTime = 1;
    this.prevControl = "idle";
}

这些行

aiPlayer.prototype = new Player(this.game, this.character, 
                                this.x, this.y,this.health, 
                                this.control, this.facing);
aiPlayer.prototype.constructor = aiPlayer;

错了。他们错了，因为

您正在将原型设置为Player
每次创建aiPlayer的新实例时，您都在重置原型和aiPlayer原型的构造函数。您应该在构造函数之外移动对原型的所有修改，如下所示：

-

function aiPlayer (game, character, x, y, health) {
    Player.call(this, game, character, x, y, health, PLAYER2_CONTROLS, "left");
    this.controls = PLAYER2_CONTROLS;
    this.attackLength = 50;
    this.fleeLength = 70;
    this.moveTime = 1;
    this.prevControl = "idle";
}

aiPlayer.prototype.someMethod = function someMethod() { 
    ....
}

设置子类原型的正确方法就是这样

aiPlayer.prototype = Object.create(Player.prototype, {
    constructor : {
        value : aiPlayer
    }
};

这将为aiPlayer原型设置一个新对象，该对象继承自Player.prototype（即Player.prototype作为其原型）并且aiPlayer已注册为其构造函数< / p>

此外，.update的{{1}}是从Player调用的，因为您在此处明确地调用了它

aiPlayer

考虑到上述情况，您应该注册aiPlayer.prototype.update = function() { if((this.game.timer.gameTime % this.moveTime) > (this.moveTime * 0.9)) { this.chooseMove(); } Player.prototype.update.call(this); //you call the Player.update() };

aiPlayer.update

现在，当您创建一个新的aiPlayer.prototype = Object.create(Player.prototype, { constructor : { value : aiPlayer } }; aiPlayer.prototype.update = function update() { //your code here }对象实例时，继承链将如下所示

aiPlayer

当您致电aiPlayerInstance --> aiPlayer.prototype --> Player.prototype时，它会首先查看aiPlayerInstance.update()，因为aiPlayer.prototype确实有一个名为aiPlayer.prototype的方法，它会执行它，它看起来不会进一步沿着继承链（即update）

调用子类函数时调用超类函数

1 个答案: