Save/Attach content of editorWindow to a gameObject

Questions & Answers
1

I have a editor window where I let the user give some input which is related to a certain gameObject.
How do I save this input, so that on closing and reopening the window (and when the connection with the gameObject is somehow made again) I can show that exact same input, so that the user can reëdit it? (I am talking about positions of dragged GUI.Boxes)

Do I save it in a file, if so how? And how can the data in that file be related to the corresponding gameObject?

2

It sounds like you want to do something like this

[Serializable] 
public class SerializableGUIMetaData {
    public int x;
    public int y;
    // etc
}

public class MyScriptableObject : ScriptableObject { // MonoBehaviour should also work if the instance is in the scene
    public SerializableGUIMetaData[] boxData = new SerializableGUIMetaData[1];
    
}

public class MyEditorClass : Editor {
    MyScriptableObject myGUIBoxData;

    public void UpdateData() {
        myGUIBoxData.boxData[0].x = 10; // Example
        Editor.SetDirty(myGUIBoxData); // This will make it "save" for you
    }
}

Assuming the instance of MyEditorClass is a prefab or instance of a scriptable object in the scene or assets, the data should just be saved.

To create an instance of a scriptable object (if you didn’t already), you’ll want to do something like this:

T asset = ScriptableObject.CreateInstance<T> ();
string assetPathAndName = AssetDatabase.GenerateUniqueAssetPath (path + "/New " + typeof(T).ToString() + ".asset");
AssetDatabase.CreateAsset (asset, assetPathAndName);
AssetDatabase.SaveAssets ();

Edit:
Another way that might be more suitable depending on your goals, is importing and exporting the data as a json. Shouldn’t be too difficult to find a class to turn a class into a json string for you via reflection.