Dynamically add JCheckBoxes

Question

Is there a way to add dynamically items of type JCheckBox in Java as in JComboBox we use addItem method?

What i want to do is, after selected something in my program, generate a number of other choices depending on that selection, so i've thought to jCheckList, because i want to choose more than one option. — alessandrob, Sep 19 '13 at 08:57
There are some tricks to "adding components at run-time". The [nested layout example](http://stackoverflow.com/a/5630271/418556) shows how to adds labels dynamically. — Andrew Thompson, Sep 19 '13 at 09:13
*"..because i want to choose more than one option."* Use a `JList`. — Andrew Thompson, Sep 19 '13 at 09:15
`JList` is ok but i don't know if there's the possibility to add ticks, instead of selecting more items by pressing CTRL button on keyboard — alessandrob, Sep 19 '13 at 09:32
*"`JList` is ok but i don't know if there's the possibility to add ticks"* There is. It can be done in the rendering component. — Andrew Thompson, Sep 19 '13 at 09:41

score 1 · Answer 1 · answered Sep 19 '13 at 08:59

1

Something like this may be effective if you want to add multiple items to another Component:

List<Component>  myList = new Arraylist<Component>() //List for storage
Item myItem = new Item(); //New component
myList.add(myItem);  //Store all the components to add in the list

for(int i = 0; i < myList.size; i++){
myjCheckBox.add(myList[i]); //Add all items from list to jCheckBox
}

The above example uses this method inherited in jCheckBox and should be able to provide what you need

Hope it helps!

answered Sep 19 '13 at 08:59

Levenal

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Is there also some way to take account of items selected in the JCheckbox then? – alessandrob Sep 19 '13 at 09:11
Do you mean something like storing the items selected from your JCheckBox into a list also? – Levenal Sep 19 '13 at 09:31
Yes, i want to store items selected in my JCheckBox and reuse on my program – alessandrob Sep 19 '13 at 09:36
Your going to need to add a listener, I suggest you start here http://www.java2s.com/Tutorial/Java/0240__Swing/CheckifaJCheckBoxisselectedinitsitemchangelistener.htm :) – Levenal Sep 19 '13 at 10:10

score 1 · Answer 2 · answered Sep 19 '13 at 09:58

JCheckList

Note you might use actual check-boxes for the rendering component, but this was a few lines shorter.

import java.awt.*;
import javax.imageio.ImageIO;
import javax.swing.*;

class JCheckList {

    public static void main(String[] args) {
        Runnable r = new Runnable() {
            @Override
            public void run() {
                JPanel gui = new JPanel(new BorderLayout());

                JLabel l = new JLabel("Ctrl/shift click to select multiple");
                gui.add(l, BorderLayout.PAGE_START);

                JList<String> list = new JList<String>(
                        ImageIO.getReaderFileSuffixes());
                list.setCellRenderer(new CheckListCellRenderer());
                gui.add(list, BorderLayout.CENTER);

                JOptionPane.showMessageDialog(null, gui);
            }
        };
        // Swing GUIs should be created and updated on the EDT
        // http://docs.oracle.com/javase/tutorial/uiswing/concurrency
        SwingUtilities.invokeLater(r);
    }
}

class CheckListCellRenderer extends DefaultListCellRenderer {

    String checked = new String(Character.toChars(9745));
    String unchecked = new String(Character.toChars(9746));

    @Override
    public Component getListCellRendererComponent(
            JList list,
            Object value,
            int index,
            boolean isSelected,
            boolean cellHasFocus) {
        Component c = super.getListCellRendererComponent(
                list,value,index,isSelected,cellHasFocus);
        if (c instanceof JLabel) {
            JLabel l = (JLabel)c;
            String s = (isSelected ? checked : unchecked) + (String)value;
            l.setText(s);
        }

        return c;
    }
}

Dynamically add JCheckBoxes

2 Answers2