TypeError：错误 #1009：无法访问空对象的属性或方法

Posted 2023-02-18

【中文标题】TypeError：错误 #1009：无法访问空对象的属性或方法

【英文标题】：TypeError: Error #1009: Cannot access a property or method of a null object

【发布时间】：2015-05-27 09:58:05

【问题描述】：

我的 as 代码有一些问题，如下所示，每当我的物品碰到相机时，它就会弹出：

TypeError：错误 #1009：无法访问 null 的属性或方法 对象引用。在 Prototype1/hitCamera1()

TypeError：错误 #1009：无法访问 null 的属性或方法 对象引用。在 Prototype1/hitCamera2()

TypeError：错误 #1009：无法访问 null 的属性或方法 对象引用。在 Prototype1/hitCamera3()

更新 #1：我意识到错误在于“channel3.stop();”每个命中相机上的代码。为什么上面有错误？

stop();
import flash.events.KeyboardEvent;
import flash.ui.Keyboard;
import flash.events.Event;

import flash.media.Sound;
import flash.media.SoundChannel;

var leftArrow:Boolean = false;
var rightArrow:Boolean = false;
var upArrow:Boolean = false;
var downArrow:Boolean = false;
var Test_hitting:Boolean = false;

var backSound2:VolatileReaction =  new VolatileReaction();
var channel3:SoundChannel = backSound2.play();


stage.removeEventListener(KeyboardEvent.KEY_DOWN, keydown);
stage.removeEventListener(KeyboardEvent.KEY_UP, keyup);
stage.removeEventListener(Event.ENTER_FRAME, gameloop);

stage.addEventListener(KeyboardEvent.KEY_DOWN, keyPressedDown);
stage.addEventListener(KeyboardEvent.KEY_UP, keyPressedUp);
stage.addEventListener(Event.ENTER_FRAME, movePlayer);
stage.addEventListener(Event.ENTER_FRAME, hitCamera1);
stage.addEventListener(Event.ENTER_FRAME, hitCamera2);
stage.addEventListener(Event.ENTER_FRAME, hitCamera3);

function keyPressedDown(event:KeyboardEvent)

if(event.keyCode == 37)

    leftArrow = true;
else if (event.keyCode == 39)

    rightArrow = true;
else if(event.keyCode == 38)

    upArrow = true;
   else if (event.keyCode == 40)

    downArrow = true;



function keyPressedUp (event:KeyboardEvent)

if(event.keyCode == 37)

    leftArrow = false;
else if (event.keyCode == 39)

    rightArrow = false;
else if (event.keyCode == 38)

    upArrow = false;
else if(event.keyCode == 40)

    downArrow =false;



 function hitCamera1(event:Event)
 
 if(camera1.cameralight.hitTestPoint(Player.x - Player.width/2, Player.y - Player.width/2, true))
 
     channel3.stop();
             gotoAndStop("gameover");

 
 

 function hitCamera2(event:Event)
  
 if(camera2.cameralight.hitTestPoint(Player.x - Player.width/2, Player.y - Player.width/2, true))

 
    channel3.stop();
     gotoAndStop("gameover");
 


 function hitCamera3(event:Event)

if(camera3.cameralight.hitTestPoint(Player.x - Player.width/2, Player.y - Player.width/2, true))

 
    channel3.stop();
     gotoAndStop("gameover");
 
 


 function movePlayer(event:Event)

var speed:Number = 3;

if(leftArrow)

    Player.x -=speed;
    if(Player.hitTestObject(wall1) || Player.hitTestObject(mainwallLeft)|| Player.hitTestObject(wall2) || Player.hitTestObject(wall3))
    
        Player.x +=speed;

    
    if(Player.hitTestObject(exit))
       
           channel3.stop();
           gotoAndStop("secondStage");
       



if(rightArrow)

    Player.x += speed;
    if(Player.hitTestObject(wall1) || Player.hitTestObject(mainwallRight)|| Player.hitTestObject(wall2) || Player.hitTestObject(wall3))
    
        Player.x -=speed;
    
    if(Player.hitTestObject(exit))
       
          channel3.stop();
           gotoAndStop("secondStage");
       



if(upArrow)

    Player.y -= speed;
    if(Player.hitTestObject(wall1) || Player.hitTestObject(mainwallUp)|| Player.hitTestObject(wall2) || Player.hitTestObject(wall3))
    
        Player.y += speed;
    
    if(Player.hitTestObject(exit))
       
          channel3.stop();
           gotoAndStop("secondStage");
       



if(downArrow)

    Player.y +=speed;
    if(Player.hitTestObject(wall1) || Player.hitTestObject(mainwallDown) || Player.hitTestObject(wall2) || Player.hitTestObject(wall3))
    
        Player.y-=speed;
    
    if(Player.hitTestObject(exit))
       
         channel3.stop();
           gotoAndStop("secondStage");
       




 

【问题讨论】：

当对象为null 时会触发该错误，因为它不存在或具有其他名称！所以试着验证你的相机和他们的灯......

【参考方案1】：

因为你在EnterFrame上调用了HitCamera函数，可能是“channel3”为空。

在 HitCamera1、2 和 3 上试试这个

// instead of 
channel3.stop();

// use
if( channel3 ) channel3.stop(); 

【讨论】：

当我输入 if(channel3) channel3.stop(); ，它仍然显示此行的 null。

如果 channel3 为空......它将保持为空。只是您避免在空对象上调用方法 stop() 。因此您不会收到任何运行时错误。