How to determine whether a Scene with 'name' exists (with the new SceneManager)?

Questions & Answers
1

How can I determine whether a scene exists and can be loaded or not? It seems that SceneManager.GetSceneByName(name) only returns scenes that are loaded…

5

This has worked for me. Although I’m not sure if it’s ideal.

    if (Application.CanStreamedLevelBeLoaded("sceneName")
    {
        SceneManager.LoadScene("sceneName");
    }
    else
    {
        //Go to a different scene?
    }
4

You can use SceneUtility.GetScenePathByBuildIndex to get a list of valid scene names:

List<string> scenesInBuild = new List<string>();
for (int i = 1; i < SceneManager.sceneCountInBuildSettings; i++)
{
	string scenePath = SceneUtility.GetScenePathByBuildIndex(i);
	int lastSlash = scenePath.LastIndexOf("/");
	scenesInBuild.Add(scenePath.Substring(lastSlash + 1, scenePath.LastIndexOf(".") - lastSlash - 1));
}

Then check if a scene exists with:

if(scenesInBuild.Contains(sceneName))
2

The short answer is that you can’t.

There are some ways to work around the limitation though. Checkout this post:

It’s a shame that there isn’t an easy way to get access to the build settings yet. Until Unity addresses it, I hope that post sets you in the right direction.

6

I’ve created a method that uses the SceneUtility.GetBuildIndexByScenePath method to check that a scene exists in the build path:

bool IsSceneLoadableFromPath(string scenePath)
{
    if (String.IsNullOrWhiteSpace(scenePath))
        return false;
    if (SceneUtility.GetBuildIndexByScenePath(scenePath) >= 0)
        return true;

    // Allow some extra variations on scenePath since SceneManager.LoadSceneAsync is
    // more relaxed about scene path
    if (SceneUtility.GetBuildIndexByScenePath(scenePath + ".unity") >= 0)
        return true;
    if (SceneUtility.GetBuildIndexByScenePath("Assets/" + scenePath) >= 0)
        return true;
    if (SceneUtility.GetBuildIndexByScenePath("Assets/" + scenePath + ".unity") >= 0)
        return true;
    return false;
}

You’ll notice that the method makes multiple attempts to validate the given path before finally returning the result false. I’ve implemented it like this as SceneUtility.GetBuildIndexByScenePath method is more strict/precise in the path it expects than the SceneManager.LoadSceneAsync: the latter method lets you omit ‘Assets’ directory and ‘.unity’ suffix. These additional checks accomodate these differences.

3

UPDATE - Scratch everything I’ve said below. While this should work, the OP is correct, it doesn’t… at least in 5.4.3f1 and 5.5.0f3. The quick test I ran was flawed which lead to my misunderstanding.

I’m a bit late to this party and, perhaps I’m misinterpreting the question, but, the following seems to work just fine for me in Unity 5.4.3f1:

public void LoadScene(string argScene)
{
    if (UnityEngine.SceneManagement.SceneManager.GetSceneByName(argScene).IsValid())
    {
         < Load My Scene >
    }
    else
    {
        Debug.LogWarning("Load Scene Failed. " + argScene + " not found.");
    }
}

If I attempt to load a non-existent scene, the .IsValid() function returns FALSE and I dump into my warning message block.