我正在使用ActionScript3制作游戏，我遇到了一个问题。 自从我上次保存并重新启动电脑后，运行代码时出现 1009错误：
TypeError: Error #1009: Cannot access a property or method of a null object reference.
at Tower1()
at GameOfGames$cinit()
at global$init()
我正在使用4个类和1个fla文件。以下代码：
主要班级：
package {
import flash.display.*;
import flash.ui.*;
import flash.events.*;
public class GameOfGames extends MovieClip {
//Initial var's
//startScreen
public var startButton = new start_btn;
public var creditsButton = new credits;
public var background1 = new bg1;
public var txt_lannister1 = new txt_lannister;
//HowToPlay
public var gameScreen1 = new GameScreen;
public var goButton = new playGame;
//Sprites
public var enemy1 = new nedStark;
public var twr_1 = new Tower1;
public static var twr_2 = new Tower1;
public var turnBlock1 = new turnBlock;
public var turnBlock2 = new turnBlock;
public var turnBlock3 = new turnBlock;
public static var towerArray:Array = []
//Map
public var throne1 = new Throne();
public var lanes1 = new lanes;
public var emptyInterface = new interfaceEmpty;
public var cash:int = 100;
public function GameOfGames() {
// Listeners
startButton.addEventListener(MouseEvent.CLICK, clickStartButton);
//CreditsButyton.addEventListener(MouseEvent.CLICK, clickCreditsButton);
goButton.addEventListener(MouseEvent.CLICK, clickGoButton);
addEventListener(Event.ENTER_FRAME, update);
// Initial
stage.addChild(background1);
background1.x = stage.stageWidth /2;
background1.y = stage.stageHeight /2;
stage.addChild(txt_lannister1);
txt_lannister1.x = stage.stageWidth /2;
txt_lannister1.y = stage.stageHeight /2 - 50;
stage.addChild(startButton);
startButton.x = 860;
startButton.y = 590;
stage.addChild(creditsButton);
creditsButton.x = 100;
creditsButton.y = 590;
// -130 5
}
public function update (e:Event)
{
if (twr_1.hitTestPoint(enemy1.x-50, enemy1.y, true))
{
enemy1.gotoAndPlay(28);
//removeEventListener(Event.ENTER_FRAME, update);
nedStark.speedX = 0;
enemy1.x += 3;
}
if (twr_2.hitTestPoint(enemy1.x-50, enemy1.y, true))
{
enemy1.gotoAndPlay(28);
//removeEventListener(Event.ENTER_FRAME, update);
nedStark.speedX = 0;
enemy1.x += 3;
}
if (turnBlock1.hitTestPoint(enemy1.x-50, enemy1.y, true))
{
nedStark.speedX = 1.5;
nedStark.speedY = 3;
}
if (throne1.hitTestPoint(enemy1.x-50, enemy1.y, true))
{
enemy1.gotoAndPlay(28);
trace("throneattack");
nedStark.speedX = 0;
nedStark.speedY = 0;
enemy1.x += 3;
}
if (enemy1.currentFrame == 42)
{
Tower1.currentHp -= 50;
Tower1.changeHpBar();
}
}
public function clickStartButton (e:MouseEvent)
{
stage.removeChild(startButton);
stage.removeChild(creditsButton);
stage.removeChild(txt_lannister1);
stage.removeChild(background1);
stage.addChild(gameScreen1);
gameScreen1.x = 960/2;
gameScreen1.y = 640/2;
stage.addChild(goButton);
goButton.x = 860;
goButton.y = 590;
}
public function clickGoButton (e:MouseEvent)
{
stage.removeChild(goButton);
stage.removeChild(gameScreen1)
stage.addChild(lanes1);
lanes1.x = 100;
lanes1.y = -60;
lanes1.scaleY = 1.15;
stage.addChild(turnBlock1);
turnBlock1.x = 180,35;
turnBlock1.y = 430,85;
turnBlock1.scaleY = 3.55;
stage.addChild(turnBlock2);
turnBlock2.x = 180,35;
turnBlock2.y = 640/2 - 75;
turnBlock2.scaleY = 3.55;
stage.addChild(turnBlock3);
turnBlock3.x = 180,35;
turnBlock3.y = 20;
turnBlock3.scaleY = 3.55;
stage.addChild(twr_1);
twr_1.x = 319,3;
twr_1.y = 480;
stage.addChild(throne1);
throne1.x = 20;
throne1.y = 640/2 - 75
stage.addChild(enemy1);
enemy1.x = stage.stageWidth *0.95;
enemy1.y = stage.stageHeight /2 + 100;
enemy1.scaleX = 0.40;
enemy1.scaleY = 0.40;
stage.addChild(emptyInterface);
emptyInterface.y = 520;
emptyInterface.x = 0;
;
}
}
}
接口类：
package {
import flash.events.*;
import flash.display.*;
import flash.text.*;
public class interfaceEmpty extends MovieClip{
public static var currentWave:int = 0;
public static var currentCash:int = 1000;
public function interfaceEmpty() {
addEventListener(Event.ENTER_FRAME, newWave)
next_wave.addEventListener(MouseEvent.CLICK, nextWave);
twr_1_drag1.addEventListener(MouseEvent.MOUSE_DOWN, startDragging);
twr_1_drag1.addEventListener(MouseEvent.MOUSE_UP, stopDragging)
}
public function newWave(e:Event):void
{
this.waveText.text = currentWave.toString();
this.cashText.text = currentCash.toString();
}
public function nextWave (e:MouseEvent)
{
currentWave += 1;
}
public function startDragging (e:MouseEvent)
{
twr_1_drag1.startDrag();
twr_1_drag1.gotoAndStop(2);
}
public function stopDragging (e:MouseEvent)
{
twr_1_drag1.stopDrag();
addTower();
twr_1_drag1.x = 215,3;
twr_1_drag1.y = 8;
twr_1_drag1.gotoAndStop(1);
}
public function addTower()
{
addChild(GameOfGames.twr_2);
GameOfGames.twr_2.x = mouseX;
GameOfGames.twr_2.y = mouseY;
}
}
}
敌人类：
package {
import flash.display.*;
import flash.events.*;
public class nedStark extends MovieClip {
public var maxHp:int = 100;
public var currentHp:int = maxHp;
public var percentHp:Number = currentHp / maxHp;
public var healthbar = new lifeBar;
public static var speedX:Number = 3;
public static var speedY:Number = 0;
public function nedStark() {
addEventListener(Event.ENTER_FRAME, update);
addEventListener(MouseEvent.CLICK, clickEnemy);
addChild(healthbar);
healthbar.x = -2,6;
healthbar.y = -197,75;
healthbar.scaleX = 0.15;
healthbar.scaleY = 0.15;
}
public function update (e:Event)
{
x -= speedX;
y -= speedY
if (currentFrame == 25)
{
this.parent.removeChild(this);
}
}
public function clickEnemy(e:MouseEvent)
{
trace(currentHp);
currentHp -= 10;
if(currentHp <= 0)
{
removeEventListener(MouseEvent.CLICK, clickEnemy);
speedX = 0;
currentHp = 0;
gotoAndPlay(2);
trace("udeadbro?");
neddie.mouseEnabled = false;
interfaceEmpty.currentWave += 1;
interfaceEmpty.currentCash += 100;
}
changeHpBar ();
}
public function changeHpBar():void
{
percentHp = currentHp / maxHp;
healthbar.barColor.scaleX = percentHp;
}
}
}
最后（塔）班：
package
{
import flash.display.*;
import flash.events.*;
public class Tower1 extends MovieClip
{
public static var maxHp:int = 100;
public static var currentHp:int = maxHp;
public static var percentHp:Number = currentHp / maxHp;
public static var healthbar = new lifeBar();
public static var death:Boolean = false;
public function Tower1()
{
GameOfGames.towerArray.push(this);
addChild(healthbar);
healthbar.x = -2.6;
healthbar.y = 4.6;
healthbar.scaleX = 0.12;
healthbar.scaleY = 0.07;
addEventListener(Event.ENTER_FRAME, update);
}
public function update(e:Event)
{
if (currentHp == 0)
{
gotoAndPlay(2);
currentHp = 0;
removeEventListener(Event.ENTER_FRAME, update);
this.parent.removeChild(this);
death = true;
}
if (currentFrame == 44)
{
this.parent.removeChild(this);
}
}
public static function changeHpBar()
{
percentHp = currentHp / maxHp;
healthbar.barColor.scaleX = percentHp;
}
}
我不知道如何在此错误后继续前进。这可能是一个非常小的错误，但我不知道解决方案。
提前致谢！