Zenject: MonoBehaviour injection

Question

I'm new to Zenject and this is my first project using this asset. I'm having injection problems! Maybe someone knows what I am doing wrong or where the error might be. In the code below, _spawnArea is not initialized.

public class BootstrapIniter : MonoInstaller
{
    [SerializeField] private Camera _mainCamera;
    [Space(10)]
    [SerializeField] private Spawner _spawner;


    public override void InstallBindings()
    {
        BindMain();

        BindBallHandle();
    }
    
    
    private void BindMain()
    {
        Container.Bind<Camera>().FromInstance(_mainCamera).AsSingle();
    }

    private void BindBallHandle()
    {
        Container.Bind<Spawner>().FromInstance(_spawner).AsSingle();
    }
}



[RequireComponent(typeof(SpawnArea))]
public class Spawner : MonoBehaviour
{
    private SpawnArea _spawnArea;


    private void Awake()
    {
        _spawnArea = GetComponent<SpawnArea>();
    }

    [Inject]
    public void Construct(Camera camera)
    {
        Rect cameraRect = camera.pixelRect;
        _spawnArea.Init(cameraRect);
    }
}

Thanks in advance for the answer or direction in which to look for a solution

You could get the reference for _spawnArea inside of Construct() rather than Awake, or in conjunction with it if you need to. — hijinxbassist, Jan 10 '22 at 22:22
Not a Zenject expert so .. how and when is `Construct` called? Apparently `Awake` wasn't executed before -> you seem to try to create an instance of your `Spawner` class in an unallowed way? Or is it maybe a prefab? -> not an existing instance in the scene => Awake never called — derHugo, Jan 10 '22 at 22:27
Don't use the GetComponent method in your class, inject it from your installer. — Mehmet Bütün, Jan 10 '22 at 22:44

score 1 · Accepted Answer · answered Jan 11 '22 at 06:18

I think that you did not inject your instance. From the documentaiton "FromInstance - Adds a given instance to the container. Note that the given instance will not be injected in this case. If you also want your instance to be injected at startup, see QueueForInject" (QueueForInject will queue the given instance for injection once the initial object graph is constructed). Basically you need to inject your instance for the injected methods to execute.

On the other hand I dont see the point of binding a monobehaviour from instance, as you have to generate the instance bind it to the container and then inject it. You have binding methods that do this all at once for you, check the section "Construction Methods".

Check for example: FromComponentInNewPrefabResource - Instantiate the given prefab (found at the given resource path) as a new game object, inject any MonoBehaviour's on it, and then search the result for type ResultType in a similar way that GetComponentInChildren works (in that it will return the first matching value found).

Note that for the injection to take place succesfully you have to previously wire up the dependency in the container with the Container.Bind statement so that the container knows what needs to be injected and how.

I suggest to read carefully the documentation which is very good and follow the examples along.

score 0 · Answer 2 · answered Aug 05 '23 at 14:25

0

Most simple way (because Injection can occur before "local" Awake()):

[Inject]
public void Construct(Camera camera)
{
    _spawnArea = GetComponent<SpawnArea>();
    Rect cameraRect = camera.pixelRect;
    _spawnArea.Init(cameraRect);
}

answered Aug 05 '23 at 14:25

Denis Sivtsov

120
1
12

Zenject: MonoBehaviour injection

2 Answers2