Serialisation not working when inheriting from monobehaviour - unity3d

Question

Im trying to do a property drawer for a class that i need to be updated as well as editable from the editor.
If i make the class a monobehaviour the serialisation stops working, but if i remove the monobehaviour inheritance it wont update with the game loop.
Is there any way to have both? I would need the object to be able to instantiate with default (empty) values if a monobehaviour script has non instantiated reference.
[Serializable]
public class MySmallTestProp : MonoBehaviour, ISerializationCallbackReceiver
{
[SerializeField]
private string name;
[SerializeField]
private string _name;
[SerializeField]
private float _someFloat;
public float someFloat;
public MySmallTestProp()
{ }
public void OnBeforeSerialize()
{
_name = name;
}
public void OnAfterDeserialize()
{
name = _name;
}
}
[CustomPropertyDrawer(typeof(MySmallTestProp))]
public class MySmallTestPropPropertyDrawer : PropertyDrawer
{
float rowHeight;
int rowSpacing = 5;
int index;
Rect currentPosition;
public override float GetPropertyHeight(SerializedProperty prop, GUIContent label)
{
rowHeight = base.GetPropertyHeight(prop, label);
var rows = 2;
if (Application.isPlaying)
{
rows++;
}
else
{
rows++;
}
return rowHeight * rows;
}
public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
index = 1;
currentPosition = position;
EditorGUI.BeginProperty(position, label, property);
var nameProp = property.FindPropertyRelative("_name");
EditorGUI.PropertyField(NextPosition(), nameProp, new GUIContent("Name"));
EditorGUI.EndProperty();
}
Rect NextPosition()
{
currentPosition.height = rowHeight;
currentPosition.y = rowSpacing + (rowHeight + rowSpacing) * index++;
return currentPosition;
}
}

Answer 1

So if I understand you correctly what you want to achieve is having a class which is
Serializable
has some default field values
Receives an Update call every frame
Actually I don't think you need any custom property drawer for this.
First two points are as simple as having e.g.
[Serializable]
public class Example
{
// By default this has the value "Default String"
public string someString = "Default String";
// This can be edited only via the Inspector
// by default it is 42
[SerializeField] private float someFloat = 42.0f;
// This is a read-only public access
public float SomeFloat => someFloat;
}
Now to the last and tricky part - the update calls.
The easiest way is to have a dedicated MonoBehaviour like e.g.
public class UpdateDispatcher : MonoBehaviour
{
// Storing the instance for Singleton Pattern
private static UpdateDispatcher _instance;
// Register to this event to receive one call each Update
public static event Action OnUpdate;
// This method is automatically called by Unity when the application is started
// or you enter play mode in the editor
[RuntimeInitializeOnLoadMethod]
private static void Init()
{
// _instsnce is already assigned and alive?
if(_instance) return;
// Otherwise search for one in the scene
_instance = FindObjectOfType<UpdateDispatcher>();
// Found one?
if(_instance) return;
// Otherwise create it now
_instance = new GameObject(nameof(UpdateDispatcher)).AddComponent<UpdateDispatcher>();
}
private void Awake ()
{
// Does another instance already exist?
if(_instance && _instance != this)
{
// Destroy this one
Destroy (gameObject);
return;
}
// Otherwise assign this as the instance and make sure it isn't destroyed when the scene chsnges
_instance = this;
DontDestroyOnLoad (gameObject);
}
private void Update ()
{
// Call the event every frame if something is registered
OnUpdate?.Invoke ();
}
}
And then you can use ISerislizationCallbackReceiver but not for actually doing the serialization (it is already done automatically for the fields) but rather for registration to the update callback like e.g.
[Serializable]
public class Example, ISerializationCallbackReceiver
{
// By default this has the value "Default String"
public string someString = "Default String";
// This can be edited only vis the Inspector
// by default it is 42
[SerializeField] private float someFloat = 42.0f;
// This is a read-only public access
public float SomeFloat => someFloat;
// Nothing to do here, only needed for the interface
public void OnBeforeSerialize() { }
public void OnAfterDeserialize()
{
// Register to the Update event
// It is save to unregister before registering even if we haven't been registered before
// this makes sure we are registered only exactly once
UpdateDispatcher.OnUpdate -= Update;
UpdateDispatcher.OnUpdate += Update;
}
private void Update ()
{
someFloat += Time.deltaTime;
}
}

Answer 2

This answer should be more like a comment, but due to the extension I've decided to post it here.
The objective of a PropertyDrawer is to display properties differently on the editor.
To achieve that you need 2 things:
1.One class that inherits from PropertyAttribute, this will be the reference used in your future scripts.
2.Another class that inherits from PropertyDrawer, here you can type HOW to display the attribute.
One implementation example of a property drawer that shows an attribute without leting the user to edit it from editor:
using UnityEditor;
using UnityEngine;
public class DisplayWithoutEdit : PropertyAttribute
{
}
[CustomPropertyDrawer(typeof(DisplayWithoutEdit))]
public class DisplayWithoutEditDrawer : PropertyDrawer
{
public override float GetPropertyHeight(SerializedProperty property, GUIContent label)
{
return EditorGUI.GetPropertyHeight(property, label, true);
}
public override void OnGUI(Rect position, SerializedProperty property, GUIContent label)
{
GUI.enabled = false;
EditorGUI.PropertyField(position, property, label, true);
GUI.enabled = true;
}
}
Then you can use it on another script doing something like:
[DisplayWithoutEdit] public float randomNumber = 0f;