How to look up items by name in lists loaded from JSON data?

Question

I'm using a JSON file for loading texts and dialogs and here's my JSON file:

{
  "Story":
  [
    {"Name":"FirstEncounter", "Content":[
      {"id":0, "text":"sample"},
      {"id":1, "text":"sample2"}
    ]},
    {"Name":"LaGrandDuel", "Content":[
      {"id":0, "text":"sample"},
      {"id":1, "text":"sample2"}
    ]}
  ],
  "Quest1":
  [
    {"Name":"FirstEncounter", "Content":[
      {"id":0, "text":"sample"},
      {"id":1, "text":"sample2"}
    ]},
    {"Name":"QuestDetail", "Content":[
      {"id":0, "text":"sample"},
      {"id":1, "text":"sample2"}
    ]}
  ]
}

And I can load it using JsonUtility like this:

private void Start()
{
    Texts = Resources.Load<TextAsset>("Texts/Test").text;
    Root JsonData = JsonUtility.FromJson<Root>(Texts);
}

and here are the classes I use:

[System.Serializable]
public class Content
{
    public int id;
    public string text;
}

[System.Serializable]
public class Story
{
    public string Name;
    public List<Content> Content;
}

[System.Serializable]
public class Quest1
{
    public string Name;
    public List<Content> Content;
}

[System.Serializable]
public class Root
{
    public List<Story> Story;
    public List<Quest1> Quest1;
}

So setting up the whole thing is done. But, for instance, how can I access the Content related to FirstEncounter in Story? Root and Story classes use a list, not a dictionary. So I'm completely clueless about how to access different contents.

Sorry if the question seems a bit silly, I'm pretty new to JSON files.

Answer 1

how can I access the Content related to FirstEncounter in Story?

Well, you can always use List.Find:

[System.Serializable]
public class Root
{
    public List<Story> Story;
    public List<Quest1> Quest1;

    public List<Content> GetStoryContent(string storyName) {
        var match = Story.Find(s => s.Name == storyName);
        return match?.Content;
    }
}

But if you like the convenience of a dictionary, then why not just add a dictionary?

[System.Serializable]
public class NamedList<T> {
    public string name;
    public List<T> content;
}

[System.Serializable]
public class Collection<T> : ISerializationCallbackReceiver {
    public List<NamedList<T>> collection;

    Dictionary<string, List<T>> _contentLookup;

    public bool TryGetContent(string name, out List<T> content) {
        return _contentLookup.TryGetValue(name, out content);           
    }

    public void OnBeforeSerialize() {}

    public void OnAfterDeserialize() {
        _contentLookup = new Dictionary<string, List<T>>(collection.Count);
        foreach(var item in collection) {
            _contentLookup.Add(item.name, item.content);
        }
    }
}

Using generics this way, we don't need separate Story and Quest classes (even if they use different types of content), so we can avoid writing the dictionary boilerplate twice. Your Root class then becomes:

[System.Serializable]
public class Root {
    public Collection<Content> story;
    public Collection<Content> quest;
}

The ISerializationCallbackReceiver interface should cause the Unity deserializer used by JsonUtility.FromJson<T>() to call OnAfterDeserialize() on your nested types automatically.