Get selected `JCheckBox` associated `id` on swing

Question

Before I asked this question, I went through many examples, some of them are related, but did not answer my needs:

• How to get the selected index of JCheckbox?
• Java- Reading whether a checkbox is checked or not

I have a list as keyMessageList which includes id as Long and associated keyWord as String.

I displayed keyWord's name on my jpanel using following code:

    for (KeyMessage obj : keyMessageList) {
        checkBox = new JCheckBox(obj.getSmsKey());
        displayKeywordPanel.checkBooxPanel.add(checkBox);
    }

I got the following output:

Now, My requirement is: If I select keywords, I need to get the id associated with the selected keyword. I have done similar things many times in web applications like this, but now I need to do the same thing on swing. I used the following code on web application to fulfill the requirements. Code for web:

<h:selectOneMenu id="branch" value="#{createUser.branchId}" required="true" requiredMessage="Please choose branch">
          <f:selectItems value="#{allBranch}"/>
</h:selectOneMenu>

Can any swing expert please help me.

Note I may select multiple checkBox and keyMessageList returns from JPA query.

Answer 1

I have a list as keyWordsList which includes id and associated keyWord.

Don't use a List. Instead use a Map with the "keyword" as the key and the "id" as the value. Then when you select a check box you get the ID from the Map.

Another option would be to create you JCheckBox as follows:

JCheckBox checkBox = new JCheckBox(keyword);
checkbox.setActionCommand( id );

Then later you access the id of the selected checkbox by using the getActionCommand() method.

Answer 2

You can get displayKeywordPanel.checkBooxPanel.getComponents() array. Iterate through the array and store indexes. Then use the indexes to get elements from the keyMessageList

Answer 3

I think you can extend your own JCheckBox (let say JCheckBoxWithID) which allow you keep the id. Then use a List to store/remove ids everytime a checkbox is selected/unselected using an ItemListener

This way you'll be avoiding iterate over your checkboxPanel asking who is selected and keeping separated responsibilities:

• JCheckBox just shows a keyword and holds an id
• List just stores selected ids
• ItemListener handles the event when a JCheckBox becomes selected/unselected and adds/removes its id to/from List

Hope this example be helpful:

import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class Tests {

    private void initGUI(){

        /* This list will store selected ids */
        final List<Integer> selectedIds = new ArrayList<>();

        ItemListener itemListener = new ItemListener() {
            @Override
            public void itemStateChanged(ItemEvent e) {
                if(e.getSource() instanceof JCheckBoxWithID){
                    JCheckBoxWithID checkBoxWithID = (JCheckBoxWithID) e.getSource();
                    if(checkBoxWithID.isSelected()){
                        selectedIds.add(checkBoxWithID.getId());
                    } else {
                        selectedIds.remove(checkBoxWithID.getId());
                    }
                }
            }
        };

        String[] keyWords = new String[]{"Help 1", "Help 2", "Help 3", "Help 4", "Help 5", "Help 6"};
        Integer id = 0;
        JPanel checkBoxesPanel = new JPanel(new GridLayout(3,3));

        /* Add many checkbox as you keywords you have */
        for(String keyWord : keyWords){
            JCheckBoxWithID checkBoxWithID = new JCheckBoxWithID(keyWord, id);
            checkBoxWithID.addItemListener(itemListener);
            checkBoxesPanel.add(checkBoxWithID);
            id++;
        }

        JButton submit = new JButton("Submit");
        submit.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                JOptionPane.showMessageDialog(null, Arrays.toString(selectedIds.toArray()), "Selected IDs", JOptionPane.INFORMATION_MESSAGE);
            }
        });

        JPanel content = new JPanel(new FlowLayout(FlowLayout.LEADING));
        content.add(checkBoxesPanel);
        content.add(submit);

        JFrame frame = new JFrame("Demo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(content);
        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

    }

    public static void main(String[] args) {        
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Tests().initGUI();
            }
        });      
    }

    class JCheckBoxWithID extends JCheckBox {
        /* I use Integer but the id could be whatever you want, the concept is the same */
        private Integer _id;

        public JCheckBoxWithID(String text, Integer id) {
            super(text);
            _id = id;
        }

        public void setId(Integer id){
            _id = id;
        }

        public Integer getId(){
            return _id;
        }
    }
}

Here's a print screen: