Unity (C#): How do I call a List from a different Scene?

Question

Unity (C#): How do I call a List from a different Scene? I get nullReferenceException bc in the current scene, it has no variables set to it. But in the previous Scene it had the correct values and variables that I wanted. (note: the 2 scenes are different but I want to use the score as a shared value between Scenes).

Otherwise, do you have an alternative to retrieving the "frameTexts[9].text" position?

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;


public class ScoreDisplay : MonoBehaviour
{

    public Text[] rollTexts, frameTexts;
    static string output;

    public void FillRolls(List<int> rolls)
    {
        string scoreString = FormatRolls(rolls);
        for (int i = 0; i < scoreString.Length; i++)
        {
            rollTexts[i].text = scoreString[i].ToString();

        }
    }

    public void Fillframes(List<int> frames)
    {
        for (int i = 0; i < frames.Count; i++)
        {
            frameTexts[i].text = frames[i].ToString();
            Debug.Log(frameTexts[i].text + " frames");
        }
    }

    public static string FormatRolls(List<int> rolls)
    {
      //  ScoreDisplay scoreDisplay = new ScoreDisplay();
        output = "";

        for (int i = 0; i < rolls.Count; i++)
        {
            int box = output.Length + 1;                            // Score box 1 to 21 

            if (rolls[i] == 0)
            {                                   // Always enter 0 as -
                output += "-";
            }
            else if ((box % 2 == 0 || box == 21) && rolls[i - 1] + rolls[i] == 10)
            {   // SPARE anywhere
                output += "/";
            }
            else if (box >= 19 && rolls[i] == 10)
            {               // STRIKE in frame 10
                output += "X";
            }
            else if (rolls[i] == 10)
            {                           // STRIKE in frame 1-9
                output += "X ";
            }
            else
            {
                output += rolls[i].ToString();                      // Normal 1-9 bowl
            }

        }
        return output;
    }
    public string DisplayFinalScore()
    {
        string FinalScore = "Congrats on scoring: " + frameTexts[9].text;
        return FinalScore;
    }

}

let the List be static and be inside a class that doesn't inherit from monobehaviour — Daahrien, Jun 02 '17 at 04:58
Possible duplicate of [Unity - pass data between scenes](https://stackoverflow.com/questions/32306704/unity-pass-data-between-scenes) — Serlite, Jun 02 '17 at 05:04

score 2 · Answer 1 · answered Jun 02 '17 at 04:59

2

Use DontDestroyOnLoad in the script for the object that contains the variables you want to retain from one scene to another.

answered Jun 02 '17 at 04:59

Muhammad Afzaal

62
7

I used DontDestroyOnLoad as "DontDestroyOnLoad(frameTexts[i]);". However, I get the warning "DontDesotryOnLoad only works on root GameObjects or components on root GameObject". And the NullReferenceException occurs as before. Any clue why it's not working? – BenSmith Jun 02 '17 at 05:33
You can't use DontDestroyOnLoad on variables. Attach your script to a empty gameobject and call this DontDestroyOnLoad(transform.gameObject); transform.gameObject is the object you will not destroy. – rohankad Jun 02 '17 at 05:37
Please note you can simply use `DontDestroyOnLoad(gameObject)` or `DontDestroyOnLoad(this)` on a **MonoBehaviour** class (not even sure why Unity example is `DontDestroyOnLoad(transform.gameObject)`: this creates useless calls). Also remember your object holding the `DontDestroyOnLoad` script has to be a root object (not a child of another object): if the parent doesn't have a `DontDestroyOnLoad` script, its child will get deleted. – Kardux Jun 02 '17 at 08:06

score 1 · Accepted Answer · answered Jun 02 '17 at 05:37

I think your request depend on what you wanna do in your project. But i can recommend some few solutions:

Singleton (unitygeek - gist)
Save your scores in external file
PlayerPref

If you wanna keep the scores entire the whole game, i think singleton will be nice !!

score 0 · Answer 3 · answered Jun 02 '17 at 05:32

0

You can use DontDestroyOnLoad(transform.gameObject);so that the gameobject will be active in your next scene or use PlayerPrefs to save the data and load in the next scene. Both shall work!

answered Jun 02 '17 at 05:32

rohankad

79
7

Unity (C#): How do I call a List from a different Scene?

3 Answers3

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