Java Event Listeners -


i'm trying separate components of java desktop app different classes. example, have menubar class, called mainclass, creates jmenubar.

normally, implement actionlistener in menubar class , override actionperformed() keep organized. if that, how can let mainclass know clicked?

i tried implementing own actionlistener, couldn't come solution capable of dispatching events other classes.

mainclass.java

public class mainclass extends jframe {       private static void createandshowgui() {          jframe.setdefaultlookandfeeldecorated(false);         jframe frame = new jframe("main window");         frame.setdefaultcloseoperation(jframe.exit_on_close);          menubar menubar = new menubar();         jmenubar mb = menubar.createmenu();         frame.setjmenubar(mb);          frame.setsize(400,400);         frame.setvisible(true);       }       public static void main(string[] args) {         swingutilities.invokelater(new runnable() {         public void run() {            createandshowgui();         }       });     }  }

menubar.java

public class menubar implements actionlistener {       public jmenubar createmenu() {           jmenu menu;          jmenuitem item;           jmenubar menubar = new jmenubar();           menu = new jmenu("main");          menubar.add(menu);           item = new jmenuitem("new");          menu.add(item);           return menubar;     }     @override    public void actionperformed(actionevent e) {          jmenuitem source = (jmenuitem)(e.getsource());          system.out.println("action triggered on: "+source.gettext());          // *** let mainclass know clicked ??    }  }

edit

i realized can create actionlistener in mainclass , pass menubar class, this:

amended mainclass.java

actionlistener l = new actionlistener() {    public void actionperformed(actionevent ae) {      system.out.println(ae.getactioncommand());    } };  menubar menubar = new menubar(); frame.setjmenubar(menubar.createmenu(l));

and then, in menubar, apply actionlistener each of menu items.

amended menubar.java

public jmenubar createmenu(actionlistener l) {      item = new jmenuitem("hide when minimized");     item.addactionlistener(l);     menu.add(item);  }

one possible solution mainclass implements actionlistener , pass instance menubar.createmenu():

public class menubar {     public jmenubar createmenu( actionlistener l ) {       ...       menuitem.addactionlistener( l );    }    ... }

mainclass side:

public class mainclass extends jframe {     @override    public void actionperformed(actionevent e) {       object source = e.getsource();       system.out.println( "action triggered by: " + source );    }     private static void createandshowgui() {       ...       frame.setdefaultcloseoperation(jframe.exit_on_close);       menubar menubar = new menubar();       jmenubar mb = menubar.createmenu( frame );       frame.setjmenubar( mb );       ...    } }

another way use java.beans.propertychangelistener , java.beans.propertychangesupport


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