Save and Load

• Unity has a standard load/save function called PlayerPrefs.
  • It accepts only basic types such as integers and strings.
• There is also JSONUtility as a standard feature
• So complex types should be converted to strings with JSONUtility.ToJson() and stored in PlayerPrefs
• But JsonUtil has a trap.
  • Unity’s JSONUtility serializes List to {}
    • Valid as JSON so it can be read/written with FromUtility<List>, but null reference error because the content is empty
  • In the first place, you can’t serialize a List, let alone an Array.
  • Specifications.
  • Cannot serialize an Array directly, but can serialize an instance of a class that has an Array as a field
  • JsonUtil.ToJson of class Foo with Vector3[] as a field succeeds, but JsonUtil.FromJson fails to compile because the compiler does not understand how to convert to Foo.
    • FromJsonOverwrite(json, foo) on a previously created Foo instance foo will succeed.
• I thought I could create a proxy class to mediate information, and collect and distribute information with getter/setter of properties, but it seems that getter/setter is not called during serialization, so I decided to call it explicitly. cs

public class SlidePositionProxy : MonoBehaviour {
    public void BeforeGet()
    {
        Debug.Log("BeforeGet");
        var slides = GameObject.Find("MotherMonolith").GetComponent<MakeSlides>().slides;
        Debug.Log(slides.Count);
        var positions = new Vector3[slides.Count];
        for (int i = 0; i < slides.Count; i++)
        {
            positions[i] = slides[i].transform.position;
        }
        Positions = positions;
    }
    public void AfterSet()
    {
        Debug.Log("AfterSet");
        var slides = GameObject.Find("MotherMonolith").GetComponent<MakeSlides>().slides;
        for (int i = 0; i < slides.Count; i++)
        {
            slides[i].transform.position = Positions[i];
        }
    }
 
    [SerializeField]
    public Vector3[] Positions;
}
 

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