从一个类到另一个Java Swing使用相同的JComboBox

Question

I have 2 classes. I'd like to have 2 identical JComboBox in each class. I did it successfully in the first class, because the values in my JComboBox are the same as the values in a JList, filled with text from a text field. But I could not manage to get the same result in the other class !

Extract of my first class :

    DefaultComboBoxModel Ajout = new DefaultComboBoxModel();
    btnValidate.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent arg0) {
            String newCategorie = textCreerCategorie.getText();
            Ajout.addElement(newCategorie);
            list.setModel(Ajout);
            myComboB.setModel(Ajout);

So that's it ! How can I have the same JComboBox in my other class and use my JList in it ?

Answer 1

What error did you get ?

Why couldn't you instantiate a new JComboBox in your second class ? Provide some more details, so we can help you !

First of all. Are you importing the right libraries in your second class, so you can use JComboBox ? (ie javax.swing.*;)

Try creating a new instance of a JComboBox in your second class and use that. If you want to use the Ajout JComboBox that you instantiated in your first class, try and making it Global first and use it in your second class.

Once again my answer is based on assumptions. It could really help if we could see more of your code ! :)

Answer 2

You can do it using own class of ComboBoxModel :

class MyComboBoxModel extends DefaultComboBoxModel<Job> {
    public MyComboBoxModel(Job[] items) {
        super(items);
    }

    @Override
    public Job getSelectedItem() {
        Job selectedJob = (Job) super.getSelectedItem();

        // do something with this job before returning...

        return selectedJob;
    }
}

And later when you create JComboBox in any places using this model.

MyComboBoxModel myModel = new MyComboBoxModel(jobs);
JComboBox<Job> jobList = new JComboBox<Job>(myModel);

Answer 3

Thanks everyone for your answers. To be more specific, it is a shopping list where I have two class, one is for the main window where you can choose a category and product and display in a list.

The otherone is for a windows that manage your categories and products so when a categorie is created (from a jtext field and add to my jlist) I want it to add it in a ComboBox that is in the main window. I hope you guys will understand me (french girl over here).

In the modification class :

    DefaultComboBoxModel Ajout = new DefaultComboBoxModel();
    btnValiderCategorie.addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent arg0) {
            String newCategorie = textCreerCategorie.getText();
            Ajout.addElement(newCategorie);
            list.setModel(Ajout);
            ajouterACategorie.setModel(Ajout);

This allows me to add at the same time a new categorie in my jlist and in a comboBox that is in the modification windows. Then I'd like to have the same combobox in the main window so the user can choose a categorie that he created in the other class. The main class does a lot of other things but my preocupation in to have the same effect in this combobox

    JComboBox<String> categories_content = new JComboBox<String>();
    categories_content.setBounds(140, 63, 157, 30);

than the other comboBox in the modification class. Sorry guys if it's too confuse i'd understand