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Index › Programming Questions & Help › Syntax Questions › Array of object and expand method
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Array of object and expand method (Read 508 times)
jbt
Array of object and expand method
Mar 5th, 2008, 12:41am  
Hi,

I am trying to create an array of dynamic objects, which size should be able to increase. I tried ArrayList but it does not seem to take objects, does it?

Anyway, here is my code and the error I get

Code:

Ev[] aEvent = new Ev[ 1];
 
void setup() {
  size(800, 600);
  aEvent = expand(aEvent, aEvent.length+1);

}


void draw() {

}



class Ev {

  int[] x;
  Ev() {
  x = new int[100];
  };
}


Semantic Error: The type of the right sub-expression, "java.lang.Object", is not assignable to the variable, of type "Temporary_8045_9147$Ev[]".

I must be doing something wrong but I can't figure out what it is. Thank you for your help :)
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eskimoblood
Re: Array of object and expand method
Reply #1 - Mar 5th, 2008, 9:17am  
If you use ArrayList you have to cast the objects when you get them.

Code:


class Ball {
//do something here
}

ArrayList balls = new ArrayList();
balls.add(new Ball());
Ball b = (Ball)balls.get(0);//get the first ball
Ball[] bs = balls.toArray(new Ball[balls.size()]); //create an Ball array from your ArrayList
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Andreas Köberle {eskimoblood}
222550793  
JohnG
Re: Array of object and expand method
Reply #2 - Mar 5th, 2008, 3:19pm  
You need a cast to tell the program that what's being returned is really an array of Evs:

Code:
aEvent = (Ev[])expand(aEvent, aEvent.length+1);
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jbt
Re: Array of object and expand method
Reply #3 - Mar 5th, 2008, 5:19pm  
Thanks to both of you, that really helps Smiley
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