TypeError：錯誤＃1006：值不是函數 - 我做錯了什麼？

Question

首先，我通過搜索意識到這已經被問過一千次了，所以很抱歉，但我在解答答案時遇到了麻煩。我對ActionScript 3非常陌生，只是一般的新手程序員。

所以我編寫了一個簡單的遊戲，其中一些球移動並加速。但是，無論何時我調用我的碰撞檢查函數（isWithin），它都會給出錯誤＃1006：值不是函數。我是否調用或聲明瞭不正確的功能？

import flash.ui.Keyboard; 
import flash.events.Event; 
import flash.events.KeyboardEvent; 
import flash.text.TextField; 
import flash.text.TextFormat; 

// add the event listeners 
PlayerBall.addEventListener(Event.ENTER_FRAME, update); 
stage.addEventListener(KeyboardEvent.KEY_DOWN, onKeyDown); 
stage.addEventListener(KeyboardEvent.KEY_UP, onKeyUp); 

// this array holds references to all the keys 

var keys:Array = []; 

var xSpeed1:Number = 0; 
var ySpeed1:Number = 0; 

var xSpeed2:Number = 0; 
var ySpeed2:Number = 0; 

var hasFlag:int = 0; 

var collide:Boolean = false; 

function isWithin(object1:Object, object2:Object, barrier:Number):Boolean 
{ 
var distance:Number = Math.sqrt((object1.x - object2.x)(object1.x - object2.x) + (object1.y - object2.y)(object1.y - object2.y)); 

if(distance <= barrier) 
{ 
    return(true); 
} 
else 
{ 
    return(false); 
} 
} 

collide = isWithin(PlayerBall, PlayerBall2, PlayerBall.width); 
trace(collide); 

function update(e:Event):void 
{ 

// GETTING KEYBOARD INPUT FOR FRAME 
if(keys[Keyboard.UP]) 
{ 
    ySpeed1 = ySpeed1 < -5 ? ySpeed1 : ySpeed1 - .3; 
} 
if(keys[Keyboard.DOWN]) 
{ 
    ySpeed1 = ySpeed1 > 5 ? ySpeed1 : ySpeed1 + .3; 
} 
if(!(keys[Keyboard.UP]) && !(keys[Keyboard.DOWN])) 
{ 
    ySpeed1 = ySpeed1 > 0 ? ySpeed1 - .2 : ySpeed1 + .2; 
} 


if(keys[Keyboard.RIGHT]) 
{ 
    xSpeed1 = xSpeed1 > 5 ? xSpeed1 : xSpeed1 + .3; 
} 
if(keys[Keyboard.LEFT]) 
{ 
    xSpeed1 = xSpeed1 < -5 ? xSpeed1 : xSpeed1 - .3; 
} 
if(!(keys[Keyboard.RIGHT]) && !(keys[Keyboard.LEFT])) 
{ 
    xSpeed1 = xSpeed1 > 0 ? xSpeed1 - .2 : xSpeed1 + .2; 
} 

if(keys[Keyboard.W]) 
{ 
    ySpeed2 = ySpeed2 < -5 ? ySpeed2 : ySpeed2 - .3; 
} 
if(keys[Keyboard.S]) 
{ 
    ySpeed2 = ySpeed2 > 5 ? ySpeed2 : ySpeed2 + .3; 
} 
if(!(keys[Keyboard.W]) && !(keys[Keyboard.S])) 
{ 
    ySpeed2 = ySpeed2 > 0 ? ySpeed2 - .2 : ySpeed2 + .2; 
} 


if(keys[Keyboard.D]) 
{ 
    xSpeed2 = xSpeed2 > 5 ? xSpeed2 : xSpeed2 + .3; 
} 
if(keys[Keyboard.A]) 
{ 
    xSpeed2 = xSpeed2 < -5 ? xSpeed2 : xSpeed2 - .3; 
} 
if(!(keys[Keyboard.A]) && !(keys[Keyboard.D])) 
{ 
    xSpeed2 = xSpeed2 > 0 ? xSpeed2 - .2 : xSpeed2 + .2; 
} 

// MOVEMENT 

PlayerBall.x += xSpeed1; 
PlayerBall.y += ySpeed1; 

PlayerBall2.x += xSpeed2; 
PlayerBall2.y += ySpeed2; 

if(hasFlag == 1) 
{ 
    flag.x = PlayerBall.x; 
    flag.y = PlayerBall.y; 
} 
if(hasFlag == 2) 
{ 
    flag.x = PlayerBall2.x; 
    flag.y = PlayerBall2.y 
} 

// COLLISION CHECKING 

collide = isWithin(PlayerBall, flag, PlayerBall.width/2 + flag.width/2); 

if(flag.visible && collide) 
{ 
    hasFlag = 1; 
    flag.visible = false; 

    flag.x = PlayerBall.x; 
    flag.y = PlayerBall.y; 
} 

collide = isWithin(PlayerBall2, flag, (PlayerBall2.width/2 + flag.width/2)); 

if(flag.visible && collide) 
{ 
    hasFlag = 2; 
    flag.visible = false; 

    flag.x = PlayerBall2.x; 
    flag.y = PlayerBall2.y; 
} 
} 

function onKeyDown(e:KeyboardEvent):void 
{ 
    keys[e.keyCode] = true; 
} 

function onKeyUp(e:KeyboardEvent):void 
{ 
keys[e.keyCode] = false; 
} 

Answer 1

好吧，我可以在你 '無功距離' 計算髮現了問題所在。如果你的意思是乘括號內的減法值，你應該把一間「*」的結束和開始每對括號，即：

var distance:Number = Math.sqrt((object1.x - object2.x)*(object1.x - object2.x) + (object1.y - object2.y)*(object1.y - object2.y)); 

您獲得的特定錯誤，我猜，因爲編譯器將每對中的第二組括號解釋爲包含函數的參數。因此'價值不是一種功能'。

Answer 2

你缺少乘法運算符。請更改排

var distance:Number = Math.sqrt((object1.x - object2.x)(object1.x - object2.x) + (object1.y - object2.y)(object1.y - object2.y)); 

到

var distance:Number = Math.sqrt((object1.x - object2.x)*(object1.x - object2.x) + (object1.y - object2.y)*(object1.y - object2.y));