Prefab is instantiated successfully but when accessed, generate NullReferenceException in Unity

Question

I have this initialization of a prefab:

GameObject e = Instantiate(entry, new Vector3(x, y, 0), Quaternion.identity) as GameObject;

I know that it is successfully instantiated because I can see a clone on my hierarchy. However, if I try to access it, there is a NullReferenceException. I tried this:

Debug.Log(e.ToString());

And this:

e.transform.SetParent (GameObject.Find("Canvas").transform);

But it shows this error

NullReferenceException: Object reference not set to an instance of an object StudentListController.FillList (System.String strList) (at Assets/Scripts/StudentListController.cs:45) StudentListController+c__Iterator5.MoveNext () (at Assets/Scripts/StudentListController.cs:23)

This is the code of FillList:

void FillList(string strList) {
    string[] studentData;
    string[] studentList = strList.Split (';');
    int startX = -253;
    int startY = 70;
    int addX = 100;
    int addY = 30;
    for (int y = 0; y<studentList.Length; y++ ) {
        string student = studentList[y];
        studentData = student.Split(',');
        for(int x = 0; x<studentData.Length; x++) {
            string data = studentData[x];
            if (x==3) {
                data = getAgeFromBirthdate(data).ToString();
            } else if (x==4) {
                data = getSex(data).ToString();
            } 
            GameObject e = Instantiate(entry, new Vector3(startX + 100*x, startY + 40*y, 0), Quaternion.identity) as GameObject;
            //e.GetComponent<Text> ().text = data;
            //e.transform.SetParent (GameObject.Find("Canvas").transform);
        }
    }

}

your e variable is not throwing the exception , seems like the exception is being thrown by strList in the FillList method of your StudentListController — mahdi mahzouni, Jan 17 '16 at 08:46
paste the Fill method code here too , and see if newing up the strList helps , my guess is you don't new up the strList or your code is not providing it with value so it is null hence the exception — mahdi mahzouni, Jan 17 '16 at 09:51
sorry to ask but do strList , studentList and studentData have value ? also try casting the Instantiate return type and don't use the as because it will fail silently , if it fails to cast it , try it like this : (GameObject)Instantiate(.....) — mahdi mahzouni, Jan 17 '16 at 10:15

score 0 · Answer 1 · answered Jan 17 '16 at 08:53

0

Check if you have dragged and dropped anything you need in your custom components for the prefab. If you drag and drop them you should then click apply.

answered Jan 17 '16 at 08:53

Dobromir Nikolov

31
5

Yes I have dragged and drop everything – jeanl Jan 17 '16 at 08:58

Prefab is instantiated successfully but when accessed, generate NullReferenceException in Unity

1 Answers1