我一直在为一项任务进行Flash游戏，到目前为止它真的很头疼。游戏相对简单，收集物品（纪念品），避免敌人或失去健康（理智），收集屏幕上的所有物品升级（物品，玩家和敌人重置，得分保持不变），获得命中5时间，你通过屏幕获得游戏。
我有一个令人烦恼的奇怪错误。在没有任何项目的情况下进行游戏并不会给出任何错误并重置游戏（看似），但问题是：
*在获得游戏结果时有任何项目导致错误1009。
*单击任何项目的退出游戏按钮会导致错误1009。
*收集所有项目应该给出＆＃34; lvlUp＆＃34;函数，但没有任何反应，if语句永远不会触发。
我在这个问题上度过了美好的一天，并且非常接近几次破坏整个事情，所以我决定在这里咨询经验丰富的程序员。
提前为凌乱的代码道歉，我才开始使用AS3
游戏文档类代码：
package
{
import flash.events.Event;
import flash.events.MouseEvent;
import flash.display.MovieClip;
import flash.geom.Rectangle;
import player;
public class Memento extends MovieClip
{
//importing required variables
private var onScreenContent:Array;
private var playerSkill:int;
private var myXY:Array;
private var mySpeed:int;
private var border:Rectangle;
private var myMaxItems:int;
private var numItems:int;
private var numEnemies:int;
private var maxEnemies:int;
private var characterMC:player;
public var sanity:int;
public var mementos:int;
public var currentMementos:int;
//CONSTRUCTOR
public function Memento()
{
trace("initialising DOS game");
//simulates a selected skill level
playerSkill = 3;
sanity = 5;
mementos = 0;
onScreenContent = new Array ;
border = new Rectangle(30,180,870,750);
}
//code to add character into game at correct position
private function addCharacter():void
{
trace("Adding the character");
//set the initial values to character starting pos
var myXY:Array = [480,900];
var mySpeed:int = playerSkill + 6;
//create and add a new player to screen
characterMC = new player(myXY,border,mySpeed);
addChild(characterMC);
characterMC.focusRect = false;
stage.focus = characterMC;
}//end function addCharacter
//code to add items into game
private function addItems():void
{
trace("Initialising items");
//amount of items
var myMaxItems:int = playerSkill + 1;
//adding the items one at a time
for (var numItem:int = 0; numItem < myMaxItems; numItem++)
{
var thisItem:collect = new collect(border,playerSkill,characterMC);
thisItem.name = "Item";
//adding item to stage
onScreenContent.push(thisItem);
addChild(thisItem);
}//end for statement
}//end function addItems
//code to add enemies into game
private function addEnemy():void
{
trace("Adding Enemies");
//setting initial number of enemies to match game/skill level
var maxEnemies:int = playerSkill + 1;
//adding enemies one by one using a loop
for (var numEnemies:int = 0; numEnemies < maxEnemies; numEnemies++)
{
//creating a new enemy
var thisEnemy:enemy = new enemy(border,playerSkill,characterMC);
thisEnemy.name = "Enemy";
trace("adding enemies to stage");
onScreenContent.push(thisEnemy);
addChild(thisEnemy);
}
}//end function addEnemy
//code to update game scores
public function updateScores(myMC: MovieClip):void
{
//change player score if they collide with enemy or item
mementos += myMC.scoreMod;
sanity += myMC.healthMod;
if (currentMementos == 4)
{
trace("lvlup");
levelUp();
currentMementos = 0;
}//end if statement
if (myMC.name.indexOf("item") != -1)
{
var myIndex:int = onScreenContent.indexOf(myMC);
onScreenContent.splice(myIndex, 1);
currentMementos++;
}//end if statement
trace("updating player score");
//run updatescores function
displayScores();
//run gameover check
if (sanity <= 0)
{
trace("game over prompted");
gameOver();
}//end if statement
}
//function to update scores
private function displayScores():void
{
//update dynamic text fields
lifeDisplay.text = "*" + sanity;
scoreDisplay.text = "Mementos: " + mementos;
trace("displaying updated scores");
}
//function to level up
private function levelUp():void
{
// resetting all items
clearObjects();
removeChild(characterMC);
playerSkill += 1;
//resetting game stage
addCharacter();
addItems();
addEnemy();
}
public function clearObjects():void
{
//removing all remaining game objects
for each (var myObj in onScreenContent)
{
myObj.removeAsset();
myObj = null;
}
// reset the array for next level
onScreenContent = new Array();
}
//function to return from map stage back to main menu
function exitMap(event:MouseEvent):void
{
gotoAndStop(1);
//removing player
removeChild(characterMC);
clearObjects();
mementos = 0;
sanity = 5;
currentMementos = 0;
}//end function exitMap
//function to execute game over
private function gameOver():void
{
//game over script
trace("game over");
gotoAndStop(4);
clearObjects();
removeChild(characterMC);
mementos = 0;
sanity = 5;
currentMementos = 0;
}
}//end class
}//end package
敌人类代码：
package
{
import flash.events.Event;
import flash.events.MouseEvent;
import flash.display.MovieClip;
import flash.geom.Rectangle;
public class enemy extends MovieClip
{
private var borderEnemy:Rectangle;
private var charNum:int;
private var charSpeed:int;
private var charDir:int;
private var offset:int;
private var characterMC:MovieClip;
public var healthMod:int;
public var scoreMod:int;
//CONSTRUCTOR FUNCTION
public function enemy(myBorder:Rectangle, mySkill:int, player:MovieClip)
{
//set values
trace("initialising an Enemy");
mySkill = 3;
characterMC = player;
borderEnemy = new Rectangle(50,180,840,750);
//setting constraing area
borderEnemy = myBorder;
offset = 20;
//values of lives/scores
healthMod = -1;
scoreMod = 0;
//nasty type linked to mySkill
charNum = Math.ceil(Math.random() * (mySkill + 2));
charSpeed = charNum + 1;
//what can I hit?
//eventlistener: starts code when character enters stage
addEventListener(Event.ADDED_TO_STAGE, initEnemy);
addEventListener(Event.ENTER_FRAME, checkCollision);
}//end function enemy
//function to initiate enemy
private function initEnemy(evt:Event):void
{
//displaying the enemy frame (appearence) according to charNum
gotoAndStop(charNum);
//setting item positon, linked to function
setPosition();
//start movement of enemy, linked to function
addEventListener(Event.ENTER_FRAME, moveEnemy);
//remove unneeded listener after initiation
removeEventListener(Event.ADDED_TO_STAGE,initEnemy);
}//end function initEnemy
//function to set enemy position
private function setPosition():void
{
//setting enemy positions
//trace("setting enemy position");
//code to determine enemy direction
charDir = Math.floor(Math.random() * 2);
//trace("charDir value is " + charDir);
//code to determine enemy location (vertically)
var myRand:int = Math.ceil(Math.random() * 8) * (Math.ceil(Math.random() * 5) + 2);
if (charDir < 1)
{
//trace("char entering from left");
//random option 1: character appears from the left
charDir = 1;
this.x = borderEnemy.left - offset - myRand;
this.scaleX = 1;
}
else
{
//trace("char entering from right");
//random option 2: character appears from the right
charDir = -1;
this.x = borderEnemy.right + offset + myRand;
this.scaleX = -1;
}
//set verticle position using myRand
var myHeight:int = borderEnemy.bottom - borderEnemy.top - offset * 1;
this.y = Math.ceil(Math.random() * myHeight) + borderEnemy.top * 1;
}//end function setPosition
//function to move enemies
private function moveEnemy(evt:Event):void
{
if (charDir < 1)
{
this.x += - charSpeed - 10;
}
else
{
this.x += charSpeed + 10;
}
//reset character as it hits the border
if (this.x < borderEnemy.left - 40 || this.x > borderEnemy.right + 40)
{
setPosition();
}
}//end function moveEnemy
//function to check for collisions between player and enemies
private function checkCollision(evt:Event):void
{
//detecting if enemy has hit the player character
if (this.hitTestObject(characterMC))
{
trace("Hit an enemy");
MovieClip(root).updateScores(this);
setPosition();
}//end if statement
}//end function checkCollision
//function to remove enemies from map
public function removeAsset():void
{
// remove event listeners and the item
removeEventListener(Event.ENTER_FRAME, checkCollision);
//removeEventListener(Event.ENTER_FRAME, moveEnemy);
this.parent.removeChild(this);
trace("removing the enemies");
}//end function removeAsset
}//end class
}//end package
项目类代码（收集）
package
{
import flash.events.Event;
import flash.events.MouseEvent;
import flash.display.MovieClip;
import flash.geom.Rectangle;
public class collect extends MovieClip
{
private var itemNum:int;
private var borderCollect:Rectangle;
private var frameNum:int;
private var characterMC:MovieClip;
public var healthMod:int;
public var scoreMod:int;
public function collect(myBorder:Rectangle, mySkill:int, player:MovieClip)
{
borderCollect = new Rectangle(30,180,870,750);
characterMC = player;
healthMod = 0;
scoreMod = 1;
//constructor code
trace("Initialise an Item");
//constraint area for item spawn
var borderCollect = myBorder;
var offset = -200;
//which item is spawned - based on the player skill variable
var itemNum = Math.ceil(Math.random() * mySkill);
var frameNum = Math.ceil(Math.random() * 3);
//start process once item appears on stage
addEventListener(Event.ADDED_TO_STAGE,initItem);
addEventListener(Event.ENTER_FRAME, checkItems);
}//public function "collect" end, what is initiated by the class
private function initItem(evt:Event):void
{
//display frame based on itemNum
gotoAndStop(frameNum);
trace("selecting item frames");
//tun position item function
setPosition();
trace("setting item positions");
//remove no longer needed event listener
removeEventListener(Event.ADDED_TO_STAGE,initItem);
}//function initItem end
private function setPosition():void
{
var myBorder = new Rectangle(50,180,800,500);
var offset = 100;
//positioning the Item according to borders
trace("setting positions for items");
var myWidth:int = myBorder.right - myBorder.left - offset;
this.x = Math.ceil(Math.random() * myWidth) + myBorder.left * 1;
var myHeight:int = myBorder.bottom - myBorder.top - offset;
this.y = Math.ceil(Math.random() * myHeight) + myBorder.top * 1;
}//function setPosition end
private function checkItems(evt: Event):void
{
// hit the character
if (this.hitTestObject(characterMC))
{
trace("Got an Item");
MovieClip(root).updateScores(this);
removeAsset();
}//end if statement
}//end function checkCollision
public function removeAsset():void
{
// remove event listeners and the item
removeEventListener(Event.ENTER_FRAME, checkItems);
this.parent.removeChild(this);
trace("removing an Item");
}//end function removeMe
}//class end
}//package end
错误（与收集的任何项目进行游戏）
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at collect/removeAsset()[H:\DIG MEDIA Post CHris\Memento - items added\collect.as:77]
at Memento/clearObjects()[H:\DIG MEDIA Post CHris\Memento - items added\Memento.as:140]
at Memento/gameOver()[H:\DIG MEDIA Post CHris\Memento - items added\Memento.as:165]
at Memento/updateScores()[H:\DIG MEDIA Post CHris\Memento - items added\Memento.as:111]
at enemy/checkCollision()[H:\DIG MEDIA Post CHris\Memento - items added\enemy.as:113]
addItem，addEnemy，addItems等也放置在连接到按钮而不是文档类的.fla帧中。我知道这是不好的做法但他们从一开始就一直在那里，当我尝试移动它时，它会引起很多问题。
无论如何，非常感谢任何愿意筛选我的（可怕的格式化）代码以找到我所犯的（可能是非常愚蠢的）错误的人，并且我再次为这些巨大的块感到遗憾代码，我只是不确定我哪里出错了。
答案 0 :(得分：0)
我必须更仔细地研究一下，找出我的解决方案究竟有效的原因。它的本质是：在某些时候，您要删除的元素要么不存在，要么不再连接到父元素。此代码将确保您尝试删除的实例存在且具有父
if (this.parent) this.parent.removeChild(this);