Question by AbdelrahmanD · Jul 11, 2022 at 01:09 PM · vr beginner nullreferenceexception null reference exception

NullReferenceException error while trying to retrieve a value from another script

I have a script called Cas$$anonymous$$erReader.cs. T$$anonymous$$s script reads items that are placed in an on-trigger area and keeps updating values in t$$anonymous$$s script such as AppleCount w$$anonymous$$ch is a variable that stores the number of apples placed in the trigger area.

AppleCount is declared as a public variable. I am then trying to access t$$anonymous$$s number from another script called Exit.cs.

T$$anonymous$$s script is as follows:

 public class Exit : MonoBehaviour
 {
     Cas$$anonymous$$erReader record;
     private void Start()
     {
         record = GetComponent<Cas$$anonymous$$erReader>();
     }
     void OnTriggerEnter()
     {            
         int myAppleCount = record.AppleCount;
         Debug.Log("Apple Count = " + myAppleCount);
     }
 }

However,

I keep receiving a NullReferenceException error.

Any idea how I can retrieve t$$anonymous$$s value?

Add comment · Show 2

andrew-lukasik · Jul 11, 2022 at 02:41 PM 0

CashierReader record; means "address to a CashierReader component". It starts null, meaning: it points to nowhere ( yes, null means exactly that and nothing else).

NullReferenceException is raised when you try to get a value of something that is null (no address). If record.AppleCount raises this exception that means that this record points to nothing/`null`.

Since you're setting this reference like this: record = GetComponent<CashierReader>(); - this error means that this gameObject has no CashierReader component attached - simple as that.

tormentoarmagedoom · Jul 11, 2022 at 03:26 PM 0

Hello! This is a standard answer.

Null Reference errors occurs when there is some variable with value null when code tries to read it. You need to learn to find your problem by your own. First, check your error code, it says the line where the problem is. Second, You need to debug the code while running, and check the states of the variables of the line at the moment the error occurs,

I'm sure you will detect what variable value is NULL. Then investigate why.

Look for some tutorials on how to debug code while running on your scripting software if don't know what I'm talking about.

Bye & good Luck!