Class Arrays

Scripting
1

Hey there,

I forget how to setup dynamic arrays for class objects. I forget the syntax :sweat_smile:.

I get “Object reference not setup to an instance of object”. I understand what this means, I have a reference to a data type, but no memory allocated to this pointer. I just forget the proper syntax to fix this.

class Actor
{
   var name;
};

function Start()
{
   var actors : Actor[];
   actors = new Actor[5];

   actors[0].name = "Joe";

   Debug.Log(actors[0].name);
}

I get a syntax error for:

actors = new Actor[5];

Thoughts?
Alex

2

this is code that was posted on another similar thread - hope it helps

//javascript class 
class TestContainer { 
   //inspector values 
   var myObject : Transform[]; 
   var max_Velocity : float; 
   var max_Force : float; 
   var distance : float; 
   var rotationSpeed : float; 
    
   function TestContainer () { 
      max_Velocity = 3.0; 
      max_Force = 0.8; 
      distance = 0.1; 
      rotationSpeed = 3.0; 
   } 
} 

//inspector values 
var totalObj = new TestContainer[10]; 
for (obj in totalObj) obj = new TestContainer();
3

oh I would forget to build a contructor lol

thank you very much

Alex

4

You don’t actually need a constructor. You do need to initialize any entry in the array you’re actually using though, whether it’s through a constructor or not.

   var actors : Actor[];
   actors = new Actor[5];
   actors[0].name = "Joe";

should be

   var actors = new Actor[5];
   actors[0] = new Actor();
   actors[0].name = "Joe";

With a constructor you could do

   var actors = new Actor[5];
   actors[0] = new Actor("Joe");

Also, your class should read:

class Actor 
{ 
   var name : String; 
};

Note that this isn’t a dynamic array. For that you’d use Array rather than an array of Actor.

–Eric

5

I tried that earlier, it wasn’t happy with the third line. It still wasn’t referring actors[0] to an instance of Actor. Once I defined a blank constructor in my class and did that, it was happy.

As for

var name : String

Thanks! I’ve been trying to find the identifier for the data type String, but I never thought of using a capital S. I just left it blank and let unity assign it.

Cheers

6

Not sure what to say…that does work, and is how you initialize an instance of a class if it doesn’t have a constructor. I’d guess there was a typo somewhere.

–Eric