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Re: Trying to set an ArrayList within an object class

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On Tue, 13 Dec 2016 09:02:50 -0800, bobr wrote:

> Hi, I'm trying to teach myself java, and am stuck on a concept that I
> wish to learn.
> 
> I'm trying to have a new object class (GroupX) that has several
> attributes, including an ArrayList that may contain one or more other
> objects (of type CyclistX).  Within my test code, when attempting to
> invoke GroupX's SetGroup method, I receive the following message:
> 
>   The method setGroup(List<CyclistX>) is undefined for the type
>   List<GroupX>
> 
> 
> Here is my code:
> 
> 
> public class Test extends PApplet {
> 	/* test */
> public void setup() {
> 	
> 	System.out.println("test");
> 	
>     List<CyclistX> riders  = new ArrayList<CyclistX>(); List<GroupX>  
>     teams   = new ArrayList<GroupX>();
> 
>     teams.add(new GroupX());
>     
> 	riders.add(new CyclistX("Froome", "Sky", 1, sky, "GBR", "x"));
> 	riders.add(new CyclistX("Costa",  "Sky", 2, sky, "POR", "x"));
> 	
>     /* THE FOLLOWING LINE FAILS, AND I DON'T KNOW WHY!! */
> 	teams.setGroup(riders);
>
setGroup is a method belonging to GroupX, not to ArrayList<GroupX>, so 
you need to first get a reference to the GroupX instance in the teams 
list and operate on that, something like this would work:

      GroupX gx = new GroupX();
      teams.add(gx);
      .... 
      gx.setGroup(riders);

or, less elegantly or readably, substitute the following for your failing 
line:

      teams.get((teams.size() -1).setGroup(riders);


**** Not tested since the code you supplied is incomplete and so 
**** not compilable (PApplet and CyclistX declarations are missing).
**** Please supply an SSCCE in future: http://sscce.org/


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |

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Trying to set an ArrayList within an object class bobr <rraupach@att.net> - 2016-12-13 09:02 -0800
  Re: Trying to set an ArrayList within an object class Eric Sosman <esosman@comcast-dot-net.invalid> - 2016-12-13 12:47 -0500
  Re: Trying to set an ArrayList within an object class Martin Gregorie <martin@address-in-sig.invalid> - 2016-12-13 17:56 +0000

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