How to Removing a Child from a Class

Question

I'm doing a drag and drop game where I used classes to place the objects on the stage:

var dermOV:dermAnswer= new dermAnswer();
addChild(dermOV);
dermOV.name= "dermO";
dermOV.x=759.55;
dermOV.y=331.65;

var bodyOV:bodyAnswer= new bodyAnswer();
addChild(bodyOV);
bodyOV.name= "bodyO";
bodyOV.x=889.10;
bodyOV.y=331.65;

var faceOV:faceAnswer= new faceAnswer();
addChild(faceOV);
faceOV.name= "faceO";
faceOV.x=629.15;
faceOV.y=331.65;

If you move one or place it, they would stay on the screen, so I tried:

if(stage.contains(dermOV)){
   removeChild(dermOV);}
if(stage.contains(faceOV)){
   removeChild(faceOV);}
if(stage.contains(bodyOV)){
   removeChild(bodyOV);}

but I get this error:

TypeError: Error #1009: Cannot access a property or method of a null object reference. at main_fla::MainTimeline/gotattoo()[main_fla.MainTimeline::frame1:46]

It is also doing this again with the null that was set on the web viewers as well. Do you have any suggestions for a fix to remove that error?

Answer 1

You output says that you have problem in gotattoo() function. Also, if your addChild(dermOV); situated at frames at the MainTimeline, then you should try to check if you object situated at stage, because you place it as child of MainTimeline object. So if check taked place at timeline to, you should use this construction

thid.contains(dermOV);