title: Modification of variables/other swing objects on button click
body: <p>Ok so basically im struggling to perform some actions with Java Swing JButtons. I have a feeling that my problem is an ease for skilled programmers so bare with my "elementary" problems:</p>
  
  <p>What i'd like to do is modify content of other JComponent and possibly modify some variables on button click. It seems relatively easy but i would like to perform it on "already declared" variables (or already created JComponents)</p>
  
  <p>Wherever i search i always get examples of cases where everything is declared from scratch inside implementation of ActionPerformed function related to specific JButton, just like here:</p>
  
  <p><a href="http://zetcode.com/tutorials/javaswingtutorial/swingevents/" rel="nofollow">http://zetcode.com/tutorials/javaswingtutorial/swingevents/</a>
  //above you can observe that in "actionPerformed" function they define new variables such as: string/date/locale/stringbuffer</p>
  
  <p>Such solution does not satisfy my needs by any means. I want to modify/show variable that was previously defined due to user click with use of function that belongs to different class.</p>
  
  <p>Ok maybe it will be more clear if i'll show you what i'd like to do on a exemplary sourcecode:</p>
  
  <pre><code>class Number_String {
  
      public String change_add_MOD (String sss){        
          String str_modified = sss + "_modified";        
          return str_modified;
      }
      public int change_plus1 (int z){        
          int z_modified = z + 1;
          return z_modified;
      }
      public static void main(String[] args) {
          // TODO code application logic here
      }
  }
  
  public class probTESTswing extends javax.swing.JFrame {
  
      public probTESTswing() {
          initComponents();
      }
  
      private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
          jLabel1.setText("done");         
          jLabel2.setText(mystring2);        
          jLabel3.setText(ns.change_add_MOD(mystring3));
      }
  
      public static void main(String args[]) {        
  
          Number_String ns=null;
          String first_str="myFIRSTstring";        
          String mystring2 = ns.change_add_MOD(first_str);
          String mystring3 = "third_str";
  
          probTESTswing testing= new probTESTswing();
          testing.setVisible(true);
      }
  }
  </code></pre>
  
  <p>Greetings to everyone who made effort to get here;)</p>
  
  <p>So lemme briefly explain:</p>
  
  <p>Main class is the "swing gui" where in main() function i initialize some variables using second class, now i want to show result of "processing" those variables with my Number_String class, however Java refuses to cooperate as my programming skills lack some fundamental knowledge as you probably noticed.</p>
  
  <p>You can observe that i want to do "it" in both ways: where inside jButton1ActionPerformed i want to access function from my Number_String class (with use of 'mystring3'), and also the other way where i'd like to access just previously defined variable(mystring2)</p>
  
  <p>ANY HELP GREATLY APPRECIATED.</p>
  
  <ul>
  <li><p>shall i "overload" jButton1ActionPerformed function (in order to take variables as a parameter)? (yes i know its private -> I created it with Netbeans Swing designer)
  --shall i design my GUI by hand and then overload them? (dunno whether such overload is possible thou)</p></li>
  <li><p>or maybe i should define some "buffer" (field for integer and field for string) for variables that i want modify  with use of my Jbutton and then put them inside "probTESTswing" class? (+ write appropriate functions to handle the other class in such way that i use its functions?)</p></li>
  <li><p>or maybe (since my Number_String does not possess any variables - just functions) move those functions to GUI class (probTESTswing)</p></li>
  <li><p>OR maybe i should use some pointers/references? (yea it seems that this is what i need here, unfortunetely pointers/references are something i know nothing about :(, however i'd like to learn it a lot, as it seems mandatory as i discovered now - hard to find tutorials thou, since as far as i know there is no pointers, and i have no clue how to use references in such way so that desired functionality would be achieved - as you can see from my problem)</p></li>
  <li><p>OR maybe there is totally different way to deal with exactly such problems/cases? </p></li>
  </ul>
  
  <p>please enlight me, i'd like to solve my problem "efficiently" in a good programming manner, in order to learn on efficient, optimal, proper and fast solutions, however im desperate for help so any advice is greatly appreciated.</p>
  
  <p>Greetings</p>