Menu bar

As for a “classical” GUI, GENIUS proposes to have a main bar menu with the GMenuBar class (on the same principle as the swing JMenuBar).

First, we will have to create a class that extends GPanel

class myPanel extends GPanel {

  myPanel () {
  }
  
}

In the constructor of this class, we will create the different items of the menu(s) using the GMenuItem class.

class myPanel extends GPanel {

  private GMenuItem itemLoad ;
  private GMenuItem itemSave;
  private GMenuItem itemQuit;
  private GMenuItem itemHelp;

  myPanel () {
  
    // We create menu items
    itemLoad = new GMenuItem("Load");
    itemSave = new GMenuItem("Save");
    itemQuit = new GMenuItem("Quit");
    itemHelp = new GMenuItem("?");
    
  }
  
}

Then, we will create the different menu(s) present in the GMenuBar using the GMenu class and associate items to this menu(s) using the add() method.

class myPanel extends GPanel {

  private GMenuItem itemLoad ;
  private GMenuItem itemSave;
  private GMenuItem itemQuit;
  private GMenuItem itemHelp;
  
  private GMenu fileMenu;
  private GMenu aboutMenu;

  myPanel () {
  
    // We create menu items
    itemLoad = new GMenuItem("Load");
    itemSave = new GMenuItem("Save");
    itemQuit = new GMenuItem("Quit");
    itemHelp = new GMenuItem("?");
    
    // We create the “File” and the "About" menu containing the previous items
    fileMenu= new GMenu("File");
    aboutMenu= new GMenu("About");
    
    // We link items to menus
    fileMenu.add(itemLoad);
    fileMenu.add(itemWrite);
    fileMenu.add(itemQuit);
    aboutMenu.add(itemHelp);
    
  }
  
}

We will initialize the menubar using the GMenuBar class, associate menu(s) to the menubar using the add() method and create a getMenuBar() method that will return it.

class myPanel extends GPanel {

  private GMenuItem itemLoad ;
  private GMenuItem itemSave;
  private GMenuItem itemQuit;
  private GMenuItem itemHelp;
  
  private GMenu fileMenu;
  private GMenu aboutMenu;
  
  private GMenuBar bar;

  myPanel () {
  
    // We create menu items
    itemLoad = new GMenuItem("Load");
    itemSave = new GMenuItem("Save");
    itemQuit = new GMenuItem("Quit");
    itemHelp = new GMenuItem("?");
    
    // We create the “File” and the "About" menu containing the previous items
    fileMenu= new GMenu("File");
    aboutMenu= new GMenu("About");
    
    // We link items to menus
    fileMenu.add(itemLoad);
    fileMenu.add(itemWrite);
    fileMenu.add(itemQuit);
    aboutMenu.add(itemHelp);
    
    // Menu Bar initialization
    bar = new GMenuBar(this);
    bar.add(fileMenu);
    bar.add(aboutMenu);
    
  }
  
  public GMenuBar getBar() { return bar; }
  
}

The GMenuBar will be associated to the main frame as this:

myPanel pan = new MyPanel();
GFrame frame = new GFrame("Test GChoice", pan, pan.getBar());

At last, we will check the action on this menu bar using the GListener interface:

public void after(GEvent e) throws Exception {

  if (e.contains(itemQuit) ){
    System.exit(0);
  }

}

Note that since the V1.2 version, it is now possible to get several menu levels.

level1Menu = new GMenu("level 1");
itemLevel11 = new GMenuItem("level 1-1");
itemLevel12 = new GMenuItem("level 1-2");
level1Menu.add(itemLevel11);
level1Menu.add(itemLevel12);
		
// FileMenu initialization
level0Menu = new GMenu("Level 0");
level0Menu.add(level1Menu);

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