unity-hierarchy-behaviour

What is it?

Its a collection of GameObject extension methods to allow for runtime instantiation a MonoBehaviour that include an Initialize method that takes type-safe arguments.

What are the Core Features?

The ability to easily add child game objects with a specified IHierarchyBehaviour that can be initialize with type-safe args.

What are the benifits?

• Control the flow of data
• Divide responsibility of components
• Visualize that responsibility
• Control lifecycles

What are the requirements?

• Unity 2018.x

How to use it

HierarchyBehaviour is entirely run via GameObject Extension methods for creation and interfaces for implementation.

public class MyClass : MonoBehaviour, IHierarchyBehaviour
{
    public void Initialize()
    {
        Debug.Log("Initialized");
    }
}

public class MyClassWithArgs : MonoBehaviour, IHierarchyBehaviour<CustomArgs>
{
    public void Initialize(CustomArgs args)
    {
        Debug.Log("Initialized with " + args);
    }
}

The Initialize methods are automatically called by the GameObjectExtention methods used to create the new instance.

• CreateChild (New, Resources, Loaded or Instantiated)
• ReplaceChild (New, Resources, Loaded or Instantiated)

However you can just add your class that implements IHierarchyBehaviour and choose to call Initialize when you prefer to.

In addition you can also implement multiple IHierarchyBehaviour's, for example:

public class LightEstimation : MonoBehaviour, IHierarchyBehaviour, IHierarchyBehaviour<Light[]>
{
    private Light[] lights;

    public void Initialize()
    {
        lights = FindObjectsOfType<Light>();
    }
    
    public void Initialize(params Light[] lights)
    {
        this.lights = lights;
    }
}

In this case the class LightEstimation has the option to be initialized via
gameObject.CreateChild<LightEstimation>(); in which it will call Initalize() with no args.

or we can do

gameObject.CreateChild<LightEstimation, Light[]>(new[]
{
    directionalLight
});

If you already have reference to it you can simply do

lightEstimation.Initialize();

or

lightEstimation.Initalize(directionalLight, pointLight);

CreateChild

With Name

var myGameObject = gameObject.CreateChild("HelloWorld");

Without Name

var myGameObject = gameObject.CreateChild();

With Arguments

var myClassWithArgs = gameObject.CreateChild<MyClassWithArgs, CustomArgs>(new CustomArgs("HelloWorld"));

Without Arguements

var myClass = gameObject.CreateChild<MyClass>();

This will create a child new GameObject and adds the component specified by the TBehaviour type parameter. The type parameter must extend MonoBehaviour and implement IHierarchyBehaviour or IHierarchyBehaviour<TArgs>. This will return the new instance of TBehaviour.

CreateChild from resources

With Arguements

var myClassWithArgs = gameObject.CreateChild<MyClassWithArgs, CustomArgs>("MyResourcePath", new CustomArgs("HelloWorld"));

Without Arguements

var myClass = gameObject.CreateChild<MyClass>("MyResourcePath");

GameObject

var myGameObject = gameObject.CreateChild(path: "MyResourcePath");

This will create a child new GameObject and adds the component specified by the TBehaviour type parameter. The type parameter must extend MonoBehaviour and implement IHierarchyBehaviour or IHierarchyBehaviour<TArgs>. This will return the new instance of TBehaviour.

CreateChild from loaded

With Arguements

var myClassWithArgs = gameObject.CreateChild<MyClassWithArgs>(prefab, new CustomArgs("HelloWorld"));

Without Arguements

var myClass = gameObject.CreateChild<MyClass>(prefab);

GameObject

var myGameObject = gameObject.CreateChild(prefab.gameObject);

This will take a pre-existing (loaded or instantiated) IHierarchyBehaviour and clone it.
The type parameter must extend MonoBehaviour and implement IHierarchyBehaviour or IHierarchyBehaviour<TArgs>.
This will return the new instance of TBehaviour.

ReplaceChild

With Arguements

var myClassWithArgs = gameObject.ReplaceChild<MyClassWithArgs, CustomArgs>(toReplace, new CustomArgs("HelloWorld"));

Without Arguements

var myClass = gameObject.ReplaceChild<MyClass>(toReplace);

You can also use ReplaceChild with resourced assets and loaded assets.

var myClassWithArgs = gameObject.ReplaceChild<MyClassWithArgs>(toReplace, "MyResourcePath");

var myClass = gameObject.ReplaceChild<MyClass>(toReplace, prefab);

This will destroy the given child MonoBehaviour and create a child new GameObject and adds the component specified by the TBehaviour type parameter.
The type parameter must extend MonoBehaviour and implement IHierarchyBehaviour or IHierarchyBehaviour<TArgs>.
This will return the new instance of TBehaviour.