ActionScript 3.0 Argument Error:2025 (Remove Child Problem)

Question

Hello everyone,

I am encountering the following error message whenever I compile my project in Adobe Flash CS4:

ArgumentError: Error #2025: The supplied DisplayObject must be a child of the caller.
    at flash.display::DisplayObjectContainer/removeChild()
    at stageRotation/spawnParticle()
    at flash.utils::Timer/_timerDispatch()
    at flash.utils::Timer/tick()

the code that generates the error is shown below:

for (var i:int = 0; i < particleArrayForward.length; i++ ) {
    if (particleArrayForward[i] != null) {
        trace("particleArrayForward[" + i + "]:" + particleArrayForward[i]);
        this.removeChild(particleArrayForward[i]);
    }
}

Any input's appreciated. Thanks. :)

Answer 1

You are removing a child from display object by looping through all the particles in the array. However I can not see where you then remove the reference to the child in the array itself. So if you loop through particleArrayFoward again you will be trying to remove a display object that was already removed which I am going to assume is happening?

for (var i:int = 0; i < particleArrayForward.length; i++ ) {
    if (particleArrayForward[i] != null) {
        trace("particleArrayForward[" + i + "]:" + particleArrayForward[i]);
        this.removeChild(particleArrayForward[i]);
        particleArrayForward[i]=null;//this will fix it but now the length of array will never shrink

    }
}

so better yet:

for (var i:int = 0; i < particleArrayForward.length; i++ ) {
    if (particleArrayForward[i] != null) {
        trace("particleArrayForward[" + i + "]:" + particleArrayForward[i]);
        this.removeChild(particleArrayForward[i]);
    }
}
particleArrayForward = new Array();
//or particleArrayForward.length = 0;

otherwise if you are not looping through that array again then somewhere you are adding a child to the array that is not a child of the display object of which you are trying to remove from.

Answer 2

removeChild throws this error when the passed argument is not a child of the parent that called the method. Are particles added as child to another sub-container within this object?

Make sure it is indeed a child of the caller:

for (var i:int = 0; i < particleArrayForward.length; i++ ) {
    if (particleArrayForward[i] != null && particleArrayForward[i].parent == this) {
        trace("particleArrayForward[" + i + "]:" + particleArrayForward[i]);
        this.removeChild(particleArrayForward[i]);
    }
}

If the particles are not direct children of this object, you can remove them using:

for (var i:int = 0; i < particleArrayForward.length; i++ ) {
    if (particleArrayForward[i] != null && particleArrayForward[i].parent != null) {
        trace("particle at " + i + " " + particleArrayForward[i]);
        trace("parent is " + particleArrayForward[i].parent);
        particleArrayForward[i].parent.removeChild(particleArrayForward[i]);
    }
}