有限 State 机器的问题“错误 CS1503：参数 1：无法从‘UIManager’转换为‘GameStateAbstract’”

Question

I'm new in Unity. I have started developing a basic game while learning but the following errors arise when trying to chain the states(it's for doing a menu system).

The errors seems to be the same:

Argument 1: cannot convert from 'UIManager' to 'GameStateAbstract'

Argument 1: cannot convert from 'UIManager' to 'GameStateAbstract' //Happends same file in another line

Argument 1: cannot convert from 'GameManager' to 'GameStateAbstract'

context(UIManager):

public class UIManager : MonoBehaviour 
{
#UIManager Singletons
private static UIManager _instance;
public static UIManager Instance
{
    get
    {
        if (_instance == null)
        {
            Debug.LogError("UIManager is NULL");
        }
        return _instance;
    }
}

#Fields
public GameObject gameOverPanel;
public GameObject onPlayOverlays;
public GameObject startMenuPanel;

public GameStateAbstract _currentState;

public readonly PlayStates onPlayStates = new PlayStates();
public readonly DeadStates onDeadStates = new DeadStates();
public readonly MenuStates onMenuStates= new MenuStates();

public void TransitionToState(GameStateAbstract state)
{
    _currentState = state;
    _currentState.EnterState(this);
}
public void Context(GameStateAbstract state)
{
    _currentState.Conditions(this);
}
void Awake()
{
    _instance = this;
    TransitionToState(onMenuStates);
}
}

Abstract State:

public abstract class GameStateAbstract 
{
public abstract void EnterState(GameStateAbstract layer); 

public abstract void Update(GameStateAbstract layer);

public abstract void Conditions(GameStateAbstract layer);
}

Concrete State:

public class MenuStates : GameStateAbstract 
{

public override void Update(GameStateAbstract layer)
{
}
public override void EnterState(GameStateAbstract layer)
{
}
public override void Conditions(GameStateAbstract layer)
{
}
}

GameManager:

public class GameManager : MonoBehaviour
{
void Update()
{
UIManager.Instance.CurrentState.Update(this);
}
}

Thanks for answering!

Answer 1

public abstract void Update(GameStateAbstract layer);

Your parameter is a 'GameStateAbstract' object but you are passing a 'GameManager' object:

UIManager.Instance.CurrentState.Update(this);

(this) in this instance is called from GameManager

Make sure you are passing valid parameters or else you will have compile errors.

Also abstract class should be extended with a child class and the child class should be used to create objects.