GetComponentInChildren returns null during Awake()

Questions & Answers
1

I’m having some trouble trying to maintain a referenceto my Controller class from each of my other classes. I’m trying to maintain this reference by calling GetComponentInParent during the Awake method, however this returns null. If I call it during the Start method, it returns as would be expected.

Say I have two objects in my Scene:

  • Controller (parent)

  • Player (child)

    public class Controller : MonoBehaviour
    {
    private Player _player;

     private void Awake()
 {
 	// Gets the object as expected
 	_player = GetComponentInChildren<Player>();
 }

    }

    public class Player : MonoBehaviour
    {
    private Controller _controller;

     private void Awake()
 {
 	// fails to get the object, returns null
 	_controller = GetComponentInParent<Controller>();
 }
 
 private void Start()
 {
 	// gets the object
 	if (_controller == null)
 		_controller = GetComponentInParent<Controller>();
 }

    }

During the Player.Awake() call, the Controller component cannot be found, and returns null. However, in the Player.Start() call, it’s found.

I really want to link up my dependencies during the Awake function for all classes - how can I achieve this?

Thanks!

Note: My script execution order dictates that the Controller script will run before the Player script, and this is visually confirmed while the debugger is attached to Unity.

2

I have done this for you. Different methods to access script of parent object from child object vice versa. [Use of GetComponentsInChildren() and GetComponentInParent()]

3 Scripts each holding a method that I am accessing : GrandParent , Parent, Child attached to 3 Objects

  • GrandParentObject
  • --------------------------- ParentObject
  • ------------------------------------------------- ParentObject

This Script Shows multiple methods of doing the same thing for better understanding. There is another way of doing it by just making a public static instance of a class and then u can use that instance directly in other class without needing to create an object of that class. I can go in detail of this one in comments if required. Thanks if it answers what you are looking for please mark it as answered. Cheers!

GrandParent Class

using UnityEngine;
public class GrandParent : MonoBehaviour {

//Method 1:  Accessing Child Script From GrandParent Script
GameObject parentObject;
GameObject childObject;
Child child;
Parent parent;

//Method 2: Accessing Child Script From GrandParent Scrip

public Transform[] childrenObjects;

void Awake () {

    print("---------------- METHOD 1 -------------");

    parentObject = transform.Find("Parent").gameObject;
    childObject = transform.Find("Parent/Child").gameObject;
    parent = parentObject.GetComponent<Parent>();
    child = childObject.GetComponent<Child>();
    child.InChild();
    parent.InParent();

    print(" --------- Method 1 short to access child -------------");

    child = this.transform.Find("Parent/Child").gameObject.GetComponent<Child>();
    child.InChild();

    //METHOD 2
    print("----- Method 2 GetComponentsInChildren When you have Alot of childrens -----");

    childrenObjects = GetComponentsInChildren<Transform>();
    
    for(int i = 0; i < childrenObjects.Length; i++)
    {

       
        if (childrenObjects*.name == "Child")*

{
child = childrenObjects*.GetComponent();*
child.InChild();
}
if (childrenObjects*.name == “Parent”)*
{
parent = childrenObjects*.GetComponent();*
parent.InParent();
}

}
print(“----- METHOD 2 With FOREACH Loop ----”);
foreach(Transform children in childrenObjects)
{
if(children.Find(“Child”)){
child = children.GetComponentInChildren();
child.InChild();
}
if(children.Find(“Parent”)){
parent = children.GetComponentInChildren();
parent.InParent();
}
}
}
public void InGrandParent()
{
print(“InGrandParent Object”);
*} *
}
----------
Child Class
----------
using UnityEngine;
public class Child : MonoBehaviour {
Transform GrandParentObject;
GrandParent gp;
Parent p;
public void Start()
{
print(“--------- METHOD 1: From Child T GRAND PARENT ---------”);
GrandParentObject = transform.root;
gp = GrandParentObject.GetComponent();
gp.InGrandParent();
print(“-----------METHOD 2: From Child to Parents ----------------”);
gp = GetComponentInParent();
gp.InGrandParent();
p = GetComponentInParent();
p.InParent();

}
public void InChild()
{
Debug.Log(“child component found”);
}
}