TheAllenChou / unity-dependency-injection

Dependency Injection Utility for Unity

A Simple Dependency Injection Utility for Unity

(Oops. It's actually a service locator rathern than dependency injection. Will clean up the terms later...)

by Ming-Lun "Allen" Chou / AllenChou.net / @TheAllenChou / Patreon

Installation Guide

Usage

Add the Inject attribute to fields of type GameObject or Component. An additional game object name can be provided to the Inject attribute to specify which game object to inject from. If no game object name is provided, the game object of the component will be used.

Call Injector.Inject to inject into fields tagged with the Inject attribute.

using UnityEngine;

using LongBunnyLabs.DependencyInjection;

public class MyComponent : MonoBehaviour
{
  [Inject] private GameObject MyGameObject;
  [Inject] private Transform MyTransform;
  [Inject] private MeshRenderer MyRenderer;
  [Inject("Other")] private GameObject OtherGameObject;
  [Inject("Other")] private Transform OtherTransform;
  [Inject("Other")] private MeshRenderer OtherRenderer;

  private void Start()
  {
    Injector.Inject(this);
  }
}

This is equivalent to:

using UnityEngine;

public class MyComponent : MonoBehaviour
{
  private GameObject MyGameObject;
  private Transform MyTransform;
  private MeshRenderer MyRenderer;
  private GameObject OtherGameObject;
  private Transform OtherTransform;
  private MeshRenderer OtherRenderer;

  private void Start()
  {
    MyGameObject    = gameObject;
    MyTransform     = gameObject.GetComponent<Transform>();
    MyRenderer      = gameObject.GetComponent<MeshRenderer>();
    OtherGameObject = GameObject.Find("Other");
    OtherTransform  = GameObject.Find("Other").GetComponent<Transform>();
    OtherRenderer   = GameObject.Find("Other").GetComponent<MeshRenderer>();
  }
}

You can also inherit your component from AutoInjectedMonoBehaviour, whose Start method calls Injector.Inject so you don't have to.

using UnityEngine;

using LongBunnyLabs.DependencyInjection;

public class MyComponent : AutoInjectedMonoBehaviour
{
  [Inject] private GameObject Self;
  [Inject] private Transform MyTransform;
  [Inject] private MeshRenderer MyRenderer;
  [Inject("Other")] private GameObject Other;
  [Inject("Other")] private Transform TheirTransform;
  [Inject("Other")] private MeshRenderer TheirRenderer;
}

If you need to override the Start method, however, you'd need to remember to call base.Start.

using UnityEngine;

using LongBunnyLabs.DependencyInjection;

public class MyComponent : AutoInjectedMonoBehaviour
{
  [Inject] private GameObject Self;
  [Inject] private Transform MyTransform;
  [Inject] private MeshRenderer MyRenderer;
  [Inject("Other")] private GameObject Other;
  [Inject("Other")] private Transform TheirTransform;
  [Inject("Other")] private MeshRenderer TheirRenderer;
  
  protected override void Start()
  {
    base.Start();
    
    // your code here
  }
}

Injector.Inject doesn't have to be called within a Start method. You can call it whereever you see fit.