Processing 1.0 - Processing Discourse - Dynamic object name creation

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Dynamic object name creation (Read 1031 times)

Karlis

Dynamic object name creation
Apr 6^th, 2010, 7:24am

Hi!

I have 9 objects: obj1, obj2, obj3, ...., obj9. They all belong to the same class.

If I press 1, I need to execute a method from obj1, if I press2, I need to execute a method from obj2 and so on. The simplest way to do this is to write if (key=='1') obj1... or with cases.

But can I concatenate the key variable to the end of obj, so I need to write this only once, like objkey... But this doesn't work. Is it possible?

Thanks in advance!

blindfish

Re: Dynamic object name creation
Reply #1 - Apr 6^th, 2010, 7:35am

Karlis wrote on Apr 6^th, 2010, 7:24am:

But can I concatenate the key variable to the end of obj, so I need to write this only once, like objkey... But this doesn't work. Is it possible

No, not easily (if at all - one of the Java experts can clarify if need be).

The simpler alternative is to store your objects in an array. Then you simply reference the index of the array... That's the tried and tested approach Wink

Where is the what if the what is in why?

Giles Senior Member Offline Posts: 252	Re: Dynamic object name creation Reply #2 - Apr 6^th, 2010, 8:32am I did a Java course last year and I remember asking my professor this exact question - and I think he said it couldn't be done... or not easily (like Blindfish said).

JohnG

Re: Dynamic object name creation
Reply #3 - Apr 7^th, 2010, 9:50am

One way around, make an array, and index it by the key press.

e.g.

Code:

obj[] objects=new obj[9];
obj[0]=new obj(.....etc....);

...

if(keypressed)
{
  if(key>='1' && <='9')
  {
    obj[key-'1'].doSomething();
    //characters can be added to and subtracted so '1'-'1' == 0, '3'-'1'=2
    // so obj[0] will get it's doSomething(); run if you press '1' etc
  }
}

Bejoscha

Re: Dynamic object name creation
Reply #4 - Apr 7^th, 2010, 10:13am

I used a different method in my JumpMan game.
( http://www.openprocessing.org/visuals/?visualID=8637 )
The class contains a char variable and which can be set f.e. during object initialization. The main program then checks the key-variable against the objects-char variable. Done. Wink

The following code demonstrates this in simple form:
Quote:

ArrayList MyList;
MyObject M;

void setup()
{
  MyList = new ArrayList(); // I like arraylists better than fixed size arrays...
  MyList.add(new MyObject('a'));
  MyList.add(new MyObject('b'));
  MyList.add(new MyObject('c'));
}

void draw(){} // Nothing drawn here. Just using the console output...

void keyReleased()
  {
    for (int i=0; i<MyList.size();i++)
      {
        M = (MyObject) MyList.get(i);
        if (key==M.HotKey) M.DOSOMETHING();
      }
  }

class MyObject
{
  char HotKey;
  MyObject(char HotKin)
  {
    HotKey=HotKin;
  }
  void DOSOMETHING()
  {
    println(" You pressed <"+HotKey+">");
  }
}

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