Slider to control object rotation cause Object reference problem

Question

I have a slider and a turret. I can move the turret with keyboard using a script that has commands like this

 transform.Rotate(turret.forward)

Now I want to move the same object using a slider, so I have tried to attach this script to the turret

 private var mySlider: UnityEngine.UI.Slider;
 var myTurret : Transform;
 
 function Start () {
     mySlider=GameObject.FindGameObjectWithTag("MySliderTag") as UnityEngine.UI.Slider;
 
 }
 
 function Update () {
     if(mySlider != null){
         myTurret.transform.rotation.eulerAngles.z = mySlider.value;
     }
 }

Unfortunately doesn't work, the turet doesn't move and if I remove the null check non mySlyder I can see the error

 *Object reference not set to an instance of an object.*

Answer 1

Best Answer

Answer by SMH17 · Jun 22, 2015 at 08:52 PM

mySlider is a GameObject you have to get the Component as UI.Slide.

Try this:

 private var mySlider: UnityEngine.UI.Slider;
 var myTurret : Transform;
 
 function Start () {
     var slider=GameObject.FindGameObjectWithTag("MySliderTag");
     mySlider=slider.GetComponent(UnityEngine.UI.Slider) as UnityEngine.UI.Slider;
 }
 
 function Update () {
         myTurret.transform.rotation.eulerAngles.z = mySlider.value;
 }

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Answer 2

Answer by brunopava · Jun 22, 2015 at 07:27 PM

You need to use "GetComponent", in doing so you won't need to cast. http://docs.unity3d.com/ScriptReference/GameObject.GetComponent.html

 mySlider = GameObject.FindGameObjectWithTag("MySliderTag").GetComponent(UnityEngine.UI.Slider);

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Slider to control object rotation cause Object reference problem

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