AsyncOperationHandle

The AsyncOperationHandle struct is returned from several methods in the Addressables API. The main purpose of the AsyncOperationHandle is to allow access to the status and result of an operation. The result of the operation will be vaild until you call AsyncOperationHandle.Release on the operation.

When the operation completes, the AsyncOperationHandle.Status will be either AsyncOperationStatus.Succeeded or AsyncOperationStatus.Failed. If successful, you can access the result through the AsyncOperationHandle.Result property.

You can periodically check the status of the operation or register for a completed callback using the AsyncOperationHandle.Complete event.

When you no longer need the resource provided by an AsyncOperationHandle return through the Addressables API, you should release through the Addressables.Release method. See Memory Management for more details

Typed vs Typeless

Most of the Addressables API will return a generic AsyncOperationHandle<T>. This allows type safety for the AsyncOperationHandle.Completed event and for the AsyncOperationHandle.Result. There is also a non-generic AsyncOperationHandle. You can convert between the generic and non-generic handles. You will get a runtime exception if you attempt to cast a non-generic handle to a generic handle of an incorrect type. Below is an example of this conversion.

AsyncOperationHandle<Texture2D> textureHandle = Addressables.LoadAsset<Texture2D>("mytexture");

// Convert the AsyncOperationHandle<Texture2D> to an AsyncOperationHandle
AsyncOperationHandle nonGenericHandle = textureHandle;

// Convert the AsyncOperationHandle to an AsyncOperationHandle<Texture2D>
AsyncOperationHandle<Texture2D> textureHandle2 = nonGenericHandle.Convert<Texture2D>();

// The exact type is required. This will throw and exception because Texture2D is required
AsyncOperationHandle<Texture> textureHandle3 = nonGenericHandle.Convert<Texture>();

AsyncOperationHandle Usage Examples

You can register for a completion event on AsyncOperationHandle.Completed:

private void TextureHandle_Completed(AsyncOperationHandle<Texture2D> handle)
{
    if (handle.Status == AsyncOperationStatus.Succeeded)
    {
        Texture2D result = handle.Result;
        // Texture ready for use
    }
}

void Start()
{
    AsyncOperationHandle<Texture2D> textureHandle = Addressables.LoadAsset<Texture2D>("mytexture");
    textureHandle.Completed += TextureHandle_Completed;
}

AsyncOperationHandle implements IEnumerator so it can be yielded in coroutines:

public IEnumerator Start()
{
    AsyncOperationHandle<Texture2D> handle = Addressables.Load<Texture2D>("mytexture");
    yield return handle;
    if (handle.Status == AsyncOperationStatus.Succeeded)
    {
        Texture2D texture = handle.Result;
        // Texture ready for use...

        // Done. Release resource
        Addressables.ReleaseHandle(handle);
    }
}

Async await is also supported through the AsyncOperationHandle.Task property.

public async Start()
{
    AsyncOperationHandle<Texture2D> handle = Addressables.Load<Texture2D>("mytexture");
    await handle.Task;
    // Task has completed. Be sure to check the Status has succeeded before getting the Result
}