Error #1010: A term is undefined and has no properties. when it is not even on the stage

[Gregor3637]

This is an error that i cant even explain to myself why does it trigger, because it doesnt trigger every time - only when i shoot like the 1st or last ship of the Array and it somehow changes and it doesnt splice itself or something like that.

So i have a doShips Function:

function doShips() {
          for (var i:int = shipArray.length - 1; i >= 0; i--) {
                    shipArray.moveDown() //what the code in the Ship and Ship2 class does -> only: this.y += 3
                    for (var bcount= _bulletsArray.length-1; bcount >= 0; bcount--) {
                              //if the bullet is touching the ship
                                        if (shipArray.hitTestObject(_bulletsArray[bcount])) {
                                        //if we get here it means there`s is a collision
                                                  removeChild(_bulletsArray[bcount]);
                                        _bulletsArray.splice(bcount,1);
                                        removeChild(shipArray);
                                        shipArray.splice(i,1);
                              }
                    }
          }
}

When i debug the FLA the error comes from

 at ArrayOfShips_newG_withTurret_fla::MainTimeline/doShips()[ArrayOfShips_newG_withTurret_fla.MainTimeline::frame1:100]

line 100 is

if (shipArray.hitTestObject(_bulletsArray[bcount])) {

before that there is a Player on the stage that shoots bullets

//handling the bullets
function doBullets(){
          //make a for loop to iterate all  the _bulletsArray on the screen
          for (var bcount:int = _bulletsArray.length-1; bcount>=0; bcount--) {
                    //make the bullets move Up
                    _bulletsArray[bcount].y -=20;
                    //if the bullet is beyond the screen remove from the stage and the Array
                    if(_bulletsArray[bcount].y < 0) {
                              removeChild(_bulletsArray[bcount])
                              _bulletsArray.splice(bcount,1);
                    }
          }
}

also a function to move the player in the X coordinate.

and also a function that positions the ships,but they are not important because i dont think they have anything to do with the error.

I can show all the code of the FLA if that is going to help somehow to solve this.

[domingguss]

you are splicing _bulletsArray, but are still looping through it.  maybe use a while?

[Gregor3637]

well if i do it with

while (shipArray.hitTestObject(_bulletsArray[bcount])) {

now it gives me

TypeError: Error #2007: Parameter hitTestObject must be non-null.

at the same line

[domingguss]

do this: 

trace("bcount: " + bcount);

trace("_bulletsArray length: " + _bulletsArray.length);  

you'll see

[Gregor3637]

Well that is strange.

when i dont shoot it gives me

_bulletsArray length: 0

bcount: 0

_bulletsArray length: 0

bcount: 0

and when i shoot

bcount: 0

_bulletsArray length: 1

bcount: 0

_bulletsArray length: 1

... bcount doesnt change ,so does the problem come from me checking if  shipArray is hitting a _bulletsArray[WITH always a 0 property/number/element].But why when i give it to be

for (var bcount:int = _bulletsArray.length-1; bcount >= 0; bcount--) {

or im totally missing the obvious.

[Andrei1-bKoviI · Accepted solution]

Try to use index loops as little as possible. Use for...each:

a. they are faster

b. they do not depend/break on removing elements from arrays in the middle of iterations.

Try this code:

function doShips():void
{
          for each(var ship:MovieClip in shipArray)
          {
                    Object(ship).moveDown() ;
                    for each(var bullet:MovieClip in _bulletsArray)
                    {
                              //if the bullet is touching the ship
                              if (ship.hitTestObject(bullet))
                              {
                                        //if we get here it means there's is a collision
                                        removeChild(bullet);
                                        _bulletsArray.splice(_bulletsArray.indexOf(bullet), 1);
                                        removeChild(ship);
                                        shipArray.splice(shipArray.indexOf(ship), 1);
                              }
                    }
          }
}