Issues working with my game menu

Questions & Answers
1

So I am writing a menu for my game and I am having the following issue where the Console spams a “object not set to an instance of an object” message every time i click on the “Start Game” option. Here is what I have for my game:

          public class MainMenuManager : MonoBehaviour {
          
	     public enum MenuState { MainDisplay, StartGame, Options, Extras, Exit}
	     public MenuState CurrentMenuState =  MenuState.MainDisplay;
	

	     MainMenu_StartGame 	obj_StartGame;

         void Awake()
         {
	        obj_StartGame = GameObject.FindGameObjectWithTag("MainMenuItems").GetComponent<MainMenu_StartGame>();
         }
         public void OnStartGame()
         {
	         CurrentMenuState = MenuState.StartGame;
         }

    void Update()
	{
		switch (CurrentMenuState) 
		{
		case MenuState.StartGame:
			obj_StartGame.ShowContent(); //NOTE: This is where I am getting the error
			break;
            }
    }

}

public class MainMenu_StartGame : MainMenuManager
{
	protected enum StartGameState { StoryMode, Trials, Return}
	protected enum StoryModeState { NewGame, LoadGame, Return}

	public MainMenu_StartGame(){
		}

	// Use this for initialization
	public void ShowContent () {Debug.Log ("Start Game");}
}

Can anyone find what I am doing wrong? I Many thanks in advance!

2

Try changing

void Awake()
{
  obj_StartGame = GameObject.FindGameObjectWithTag("MainMenuItems").GetComponent<MainMenu_StartGame>();
}

To

void Start()
{
  obj_StartGame = GameObject.FindGameObjectWithTag("MainMenuItems").GetComponent<MainMenu_StartGame>();
}
3

You can probably find a way to store the reference to that game object via the inspector. If you want a quick fix, check if that object is null and try to find it.

void Update()
{
    switch (CurrentMenuState)
    {
        case MenuState.StartGame:
            if(obj_StartGame == null)
            {
                FindObjStartGame();
                return;
            }
            obj_StartGame.ShowContent();
            break;
    }
}

void FindObjStartGame()
{
    obj_StartGame = GameObject.FindGameObjectWithTag("MainMenuItems").GetComponent<MainMenu_StartGame>();

    if(obj_StartGame == null)
        Debug.LogError("The game object or its component is null");
}