Java: Iterate JMenuItem from ArrayList with HashMaps

Question

I have a JFrame with a menubar, in which i'd like some dynamic menus, as in, depending on the size of the ArrayList with HashLists. The problem here is that i then got a dynamic amount of JMenuItems, so i need a way to get as much variables as HashLists. In this case i made the name of the variable static, but obviously that's not working on the ActionListener, since all MenuItems will have the same ActionListener.

I'm wondering how to solve this, and how to get a menu with a dynamic amount of menuitems which all have unique actionlisteners.

private ArrayList<HashMap> menuLijst;

.

    for (HashMap h : menuLijst) {
        String vraag = (String) h.get("vraag");
        JMenuItem qMenu = new JMenuItem(vraag);
        informatie.add(qMenu);
        qMenu.addActionListener(this);
    }

Thanks in advance.

I want an action to occur, for instance, show a table or a diagram in the current frame. — Tim Lagerburg, May 14 '12 at 13:56

Guillaume Polet · Accepted Answer · 2012-05-14T13:01:05.653

Depending on what you want to do in your ActionListener, you can either use this, as you do right now and in the actionPerformed you can then use ((JMenutItem)event.getSource()) to see which menu item has been clicked. Alternatively, you could register as many ActionListeners as there are menus, like this:

for (final HashMap h : menuLijst) {
    final String vraag = (String) h.get("vraag");
    final JMenuItem qMenu = new JMenuItem(vraag);
    informatie.add(qMenu);
    qMenu.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent event) {
               // here event.getSource() is the same as qMenu
               System.out.println("Menu "+qMenu+" with label "+vraag+" has been pressed");
               System.out.println("HashMap is "+h);
         }
    });
}

But to me (and also seeing your previous questions), it seems that you are abusing the usage of HashMap instead of using appropriate new objects. I don't know what else is in your HashMap, let's say that you have 3 keys: "vraag", "answer", "grade", you could create the following class:

public class MyClass {
     private String vraag;
     private String answer;
     private int grade;

     // And getters and setters here.
}

And have a List<MyClass> instead of List<HashMap>.

@TimLagerburg Sorry, I forgot to put the backtiks which prevented the typing from showing. — Guillaume Polet, May 14 '12 at 10:32

score 0 · Answer 2 · answered May 14 '12 at 09:46

0

I don't see why you want to use a HashMap for your Strings. If you save an ArrayList of Strings, and loop over them to add them all to the menu, you can add actionListeners to all of them, just as you are doing now.

In your ActionListener, check which button is clicked by looping through the ArrayList, and comparing to the name of the clicked button.

answered May 14 '12 at 09:46

Hidde

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That is because there's more data in the hashlist beside that String. That's data i wanted to call on when comparing the actionlistener with the list – Tim Lagerburg May 14 '12 at 10:18
OK, never mind that part then. Still, you can check in the ActionListener which button is clicked by comparing it to the strings in the HashMaps in the ArrayList. – Hidde May 14 '12 at 14:47
I found my way around now. Thans for your help. – Tim Lagerburg May 15 '12 at 09:46

Java: Iterate JMenuItem from ArrayList with HashMaps

2 Answers2