Get value from other script file variable Unity C#

Question

I have a weird question. I want to get value from other script file, but actually it is quick easy. But this time I have an another case.

For example:

I have player.cs that save the data with datatype dictionary

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

public class player : MonoBehaviour {

    public Dictionary <string, Dictionary <string, int> > product;

}

then I have margaretShop.cs that set the value of dictionary product

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

public class margaretShop : MonoBehaviour {
    player Player;

    // Use this for initialization
    void Start () {
        Player = GameObject.FindGameObjectWithTag ("player").GetComponent<player> ();

            setValue("A", "id", "10");
            setValue("A", "name", "A");
            setValue("A", "qty", "4");
            setValue("A", "price", "120");



    }


    // Update is called once per frame
    void Update () {

    }

    void init() {
        if (Player.product != null) {
            return;
        }
        Player.product = new Dictionary<string, Dictionary <string, int> > ();
    }

    public int getValue(string nameproduct, string property) {
        init ();

        if (Player.product.ContainsKey (nameproduct) == false) {
            return 0;
        }

        if (Player.product [nameproduct].ContainsKey (property) == false) {
            return 0;
        }

        return Player.product [nameproduct] [property];
    }

    public void setValue(string nameproduct, string property, int value) {
        init ();

        if (Player.product.ContainsKey (nameproduct) == false) {
            Player.product[nameproduct] = new Dictionary<string, int>();

        }

        Player.product [nameproduct] [property] = value; // This store to player.cs file product
    }


    public string[] getProductName() {
        return Player.product.Keys.ToArray();

    }

}

and then last I call it with another script file margaretSellScript.cs

using UnityEngine;
using System.Collections;
using System.Linq;
using UnityEngine.UI;

public class margaretSellScript : MonoBehaviour {
    margaretShop mShop;

    player Player;

    // Use this for initialization
    void Start () {
        mShop = GameObject.FindGameObjectWithTag ("MargaretShop").GetComponent<margaretShop> ();
        Player = GameObject.FindGameObjectWithTag ("player").GetComponent<player> ();

    Debug.Log("QTY : " + mShop.getValue ("A", "qty"));

    }                 
}

In this script: Debug.Log("QTY : " + mShop.getValue ("A", "qty")); why I can't get the value from player.cs product variable dictionary? The value must be "4" right?

The error is Object reference not set to an instance of an object

I have already call the gameobject like this at margaretSellScript.cs :

mShop = GameObject.FindGameObjectWithTag ("MargaretShop").GetComponent<margaretShop> ();
            Player = GameObject.FindGameObjectWithTag ("player").GetComponent<player> ();

Any Idea?

Answer 1

But i see it is attacted. Just i am not set it active until i press the button.

That's the problem. The component must be enabled in order for GetComponent<Script> () to find it. Enable it from the Editor as default. When game starts get the reference then disable it.

mShop = GameObject.FindGameObjectWithTag("MargaretShop").GetComponent<margaretShop>();
mShop.enabled = false; //disable it

If you have any code that runs in the Start() function of the margaretShop script, you can remove them and put them in a custom public function named initScript() .

Now, when you press the Button , you can activate it with mShop.enabled = false; , then call the initScript() function to initialize your variables in the margaretShop script. That's it.