koobas.hobune.stream
"Object reference not set to an instance of an object" error
I have a switch and a platform that moves upward when the switch is triggered. I'm getting the error "NullReferenceException: Object reference not set to an instance of an object" when I try to use GetComponent to use the switch's script in the platform's code. When I looked up this error message on Unity Answers a lot of people said that it was because Unity couldn't find a component I needed, so I doublechecked that the switch's script was attached to the moving platform game object, and it is--however, whenever I press play to run my game, the script disappears. Does anyone know what's going on? The code for the moving platform is:
using UnityEngine; using System.Collections;
public class MovingPlatform : MonoBehaviour
{
public SwitchScript nearSwitch;
void Awake ()
{
nearSwitch=gameObject.GetComponent<SwitchScript>();
}
void Update ()
{
if (nearSwitch.isSwitched)
transform.Translate(Vector3.up);
}
}
I plan to add code to stop the platform moving up later, I just need the switch boolean to activate the moving platform.
The code for SwitchScript is
using UnityEngine;
using System.Collections;
public class SwitchScript : MonoBehaviour
{
public bool isSwitched=false;
void OnTriggerEnter (Collider otherObject)
{
renderer.material.color=Color.green;
isSwitched=true;
}
}
You file is called movingplatform.cs (all in lower case), right?
And switchscript is called switchscript.cs (again in lowercase?)
You should really call scripts using the na$$anonymous$$g convention of a capital first letter then camel case for the other words. It makes it a lot easier to read when formatted that way and will be in line with other people's code.
Also the line nearSwitch = would be much better and safer as:
nearSwitch = gameObject.GetComponent<switchscript>();
And it would be better to cache it in Awake to give better performance.
Can you put the code for the switchscript (which should be written SwitchScript by now)?
The na$$anonymous$$g style has changed, and the SwitchScript code has been posted.
This is the code I ended up using, just inside the switch script itself. I'll leave it here for reference in case any other newbies have the same issue.
using UnityEngine;
using System.Collections;
public class ElevatorSwitchScript : MonoBehaviour
{
//all same as doorswitch.
public bool isSwitched=false;
public float platformUp=5;
public Transform elevator;
public Vector3 desiredPos = new Vector3(0f, 0f, 0f);
void OnTriggerEnter (Collider otherObject)
{
renderer.material.color=Color.green;
isSwitched=true;
}
void Update()
{
if (isSwitched==true && elevator.transform.position.y <= desiredPos.y)
elevator.transform.Translate (Vector3.up * platformUp * Time.deltaTime);
}
}
Hi TaylorAnderson,
It seems that your problem is that you are trying to Get a component out of the gameObject that has the PlatformScript and not the gameObject that has the SwitchScript, you should try to create a public variable on your platform script which contains the gameObject that has the SwitchScript so then you could use the GetComponent on that object, try something like this:
public class MovingPlatform : MonoBehaviour
{
public GameObject switchObject; // <---- in the inspector drag&drop here the gameObject that has the SwitchScript
public SwitchScript nearSwitch;
void Awake ()
{
nearSwitch=switchObject.GetComponent<SwitchScript>(); //In here change gameObject by switchObject
}
void Update ()
{
if (nearSwitch.isSwitched)
transform.Translate(Vector3.up);
}
}
Now it should work. Try it out and let us know.
Shoot, sorry, I've managed to figure it out on my own. I just put all of the code to move the platform inside of the switch script. I'll post the way I did it in a second
