Addressables.LoadContentCatalogAsync

API

• static AsyncOperationHandle<IResourceLocator> LoadContentCatalogAsync(string catalogPath, string providerSuffix = null)
• static AsyncOperationHandle<IResourceLocator> LoadContentCatalogAsync(string catalogPath, bool autoReleaseHandle, string providerSuffix = null)

Returns

AsyncOperationHandle<IResourceLocator>: An async operation handle that returns the IResourceLocator loaded by the catalog. After the operation has completed, it is safe to release this handle.

No further action is required to load the content catalog once the operation completes. The IResourceLocator returned from the operation is available but not needed to make use of the newly loaded catalog.

Best Practice

• Pass true into the autoReleaseHandle parameter.

Description

LoadContentCatalogAsync is used to load a secondary Content Catalog. The Content Catalog returns an IResourceLocator, which maps addresses to asset locations. Using this API allows you to load assets built by Addressables from a project separate than that which contains your runtime player build.

It is a common case for larger projects to split the project with asset content from the project containing runtime scripts; typically this is done to reduce import times. Addressables supports this workflow through the LoadContentCatalogAsync API. Both projects need to contain the Addressables package and build their player content for the appropriate platform. The content project must build all of its content into remote Addressable groups. Also ensure that Build Remote Catalog is turned on for the content project. From there, place the AssetBundles from the content project into the desired remote location and load the catalog in your runtime project.

It is also possible to end up with multiple secondary catalogs if you're using a custom build script to build your player content.

Once the secondary catalog is loaded, you can use the keys built into that catalog with the Addressables APIs. Also, once a secondary catalog is loaded it cannot be unloaded. The AsyncOperationHandle can safely be released or you can pass in true to the autoReleaseHandle parameter.

Once a secondary catalog is downloaded, it is cached locally if a corresponding .hash file is located alongside the catalog's .json file. The API looks for a .hash file of the same name as the catalog in the same directory as the catalog itself. The .hash file contains the current hash of the content catalog. If no .hash file can be found, the remote catalog is downloaded on all future requests. Otherwise, when loading the remote catalog on subsequent application starts, the local hash of the catalog is compared against the hash of the remote catalog at the given location. If a different hash is detected, the remote catalog is downloaded, cached, and used. If the remote and local hash match, or if there is no internet connection, the cached catalog is used.

If you need to update catalogs (either primary or secondary) during runtime, refer to the UpdateCatalogs documentation.

The providerSuffix parameter can be used to ensure unique IDs for the resource providers loaded from a given catalog. The string passed in will be appended to all provider IDs.

Code Sample

public IEnumerator Start()
{
    //Load a catalog and automatically release the operation handle.
    AsyncOperationHandle<IResourceLocator> handle = Addressables.LoadContentCatalogAsync("path_to_secondary_catalog", true);
    yield return handle;

    //...
}