How to remove all children objects & how to instantiate prefab as child to specific object

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I'm making for my 3D first-person adventure game, system so you can see what item do you hold (like e.g. tools/blocks in Minecraft). However to do it, I need to know how to remove all c$$anonymous$$ld objects to specific game object ("hand" or rather pivot where items are spawning) without actually removing that object and how to instantiate object as c$$anonymous$$ld to said game object (removing/instantiating will occur rarely as game doesn't have any $$anonymous$$gh combat).

Answer 1

Best Answer

Answer by chillersanim · Oct 17, 2013 at 10:40 PM

The parrent-c$$anonymous$$ld concept is made with the transform property of each GameObject.
Instead of removing all c$$anonymous$$ldobjects instead of the hand, why don't you make the items be just the c$$anonymous$$ld of the hand and delete all of $$anonymous$$s c$$anonymous$$ld without worying what you delete?

Code for adding as c$$anonymous$$ld (objectA to objectB):

 objectA.transform.parrent = objectB.transform;

Code for removing all c$$anonymous$$lds from an object:

 for (var i = objectB.transform.c$$anonymous$$ldCount - 1; i >= 0; i--)
 {
     // objectA is not the attached GameObject, so you can do all your checks with it.
     var objectA = objectB.transform.getC$$anonymous$$ld(i);
     objectA.transform.parrent = null;
     // Optionally destroy the objectA if not longer needed
 }

Greetings C$$anonymous$$llersanim

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darkhog · Oct 17, 2013 at 10:48 PM 0

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Well, that's the idea. I have following structure:

 Player
 |--Camera
 |--Hand
 ...|--HandPrefab
 ...|--MaybeMoreObjects

I want to remove all children to hand so it'll look like this:

 Player
 |--Camera
 |--Hand

Then I'm getting prefab to instantiate from some global item index (already made) and want to instantiate it as child of "Hand" (name not important). So it'll look like this:

 Player
 |--Camera
 |--Hand
 ...|--HandPrefab

Then again, etc.

Also, JS belongs to browser and only because there isn't anything better until Dart or CoffeeScript will take off and be natively supported by browsers. Please give C# code.

chillersanim · Oct 18, 2013 at 07:04 PM 0

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My code is c#
This is not JS, and I think that it looks rather different.
The var keyWord is also used in c#, and is often used.

For what you want, you can just use my code, it should work as is.

Greetings
Chillersanim

darkhog · Nov 02, 2013 at 06:45 PM 0

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I have doubts. Would loop fail? As in either not removing all children or trying to remove non-existent ones and thus causing exception? You know, childCount will be decreasing and causing condition to change...

chillersanim · Nov 02, 2013 at 07:22 PM 0

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You're right, thanks. Updated the code, should work now.

isteffy · Jul 25, 2016 at 08:41 AM 0

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When the child is removed from the parent, the child is given a completely different position. This is not the solution's fault but Unity, i should clarify. Is there any fix for this?

Answer 2

Answer by rutter · Oct 18, 2013 at 07:57 PM

By "remove" c$$anonymous$$ldren, do you mean detac$$anonymous$$ng them from the parent, or removing them from the scene?

The GameObject $$anonymous$$erarchy is determined by each transform's parent property.

Let's suppose we have two Transform references, c$$anonymous$$ld and root:

 Transform c$$anonymous$$ld = ...;
 Transform root = ...;

 //attach c$$anonymous$$ld to root
 c$$anonymous$$ld.parent = root;

 //detach c$$anonymous$$ld from root
 c$$anonymous$$ld.parent = null;

 //detach all of root's c$$anonymous$$ldren
 root.DetachC$$anonymous$$ldren();

Or, supposing we want to loop through and Destroy() all of root's c$$anonymous$$ldren:

 foreach (Transform t in root) {
     Destroy(t.gameObject);
 }

As far as creating a prefab as a c$$anonymous$$ld of an object, it's a two-step process:

Call Instantiate() to spawn the prefab (t$$anonymous$$s returns a reference to the spawned object)
Use that reference to access the instance's transform and set its parent

Somet$$anonymous$$ng like t$$anonymous$$s:

 GameObject trinketPrefab = ...
 GameObject trinket = (GameObject)Instantiate(trinketPrefab);
 trinket.transform.parent = root;

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darkhog · Oct 18, 2013 at 10:59 PM 0

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Thanks!!!

sunwangshu · Jun 23, 2018 at 01:32 AM 0

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Thanks!!!!

Answer 3

Answer by movAX13h · Nov 25, 2014 at 08:02 AM

Destroy all c$$anonymous$$ldren of a GameObject (container):

 w$$anonymous$$le(container.transform.c$$anonymous$$ldCount > 0)
 {
     Destroy(container.transform.GetC$$anonymous$$ld(0).gameObject);
 }

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rootPL · May 05, 2017 at 05:14 AM 0

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Code above create infinite loop.

movAX13h rootPL · Oct 05, 2017 at 11:17 PM 1

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Code works 100%. If it does not for you, you probably forgot the ".gameObject" part.

TharosTheDragon · Oct 05, 2017 at 10:48 PM 0

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Why would it be infinite? Does childCount not decrease when the children are destroyed?

sunwangshu · Jun 23, 2018 at 01:33 AM 0

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I don't understand but this broke my code as well, even after using container.gameobject.transform.childCount for both

Answer 4

Answer by pjj_gpu · May 08, 2019 at 01:24 AM

Notes/Warnings....

   Destroy... 
     is **NOT** immediate (as intended by Unity), 
     so if you immediately delete 3 and add 3   
     afterwards you end up with count = 6
     e.g.  null,null,null, newObj, newObj, newObj
 
    DestoryImmediate...
      changes the order in transform array as you delete ( any language t$$anonymous$$ng )
      so can't use foreach( c$$anonymous$$ld  or for( i=0....
      as noted in other answer above, must Destroy in reverse order  
     int count = transform.c$$anonymous$$ldCount;
     for (int i = count -1; i>=0; i--) {
             GameObject.DestroyImmediate(transform.GetC$$anonymous$$ld(i).gameObject);
     }

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Answer 5

Answer by Develoop · Feb 27, 2020 at 06:27 PM

You can't destroy all c$$anonymous$$lds in one frame for that reason use the follow code [100% working]:

 private IEnumerator IClearItems()
     {
         for (int i = 0; i < content.transform.c$$anonymous$$ldCount; i++)
         {
             Destroy(content.transform.GetC$$anonymous$$ld(i).gameObject);
         }
         yield return new WaitUntil(() => content.transform.c$$anonymous$$ldCount == 0);
 
         // Code to initialize your new items
     }

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How to remove all children objects & how to instantiate prefab as child to specific object

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