Maikyl Maikyl - 5 months ago 27
Java Question

JCheckBox enables/disables JRadioButton

I have a group of JRadioButtons and a single JCheckBox. If the JCheckBox is unchecked, the JRadioButtons should disable and reset, and vice versa. The problem I have is whether I check the JCheckBox or not, the JRadioButtons stay disabled.

Also before going on to the code, don't mind the null layout and absence of different classes. I quickly made a test project to reduce the amount of code I would have to paste here.

package test;

import javax.swing.ButtonGroup;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JRadioButton;
import javax.swing.JPanel;

public class Test {

public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JPanel panel = new JPanel();
panel.setBounds(0, 0, 434, 261);
frame.getContentPane().add(panel);

JCheckBox ckbxTestCheckBox = new JCheckBox("Test Check Box");
ckbxTestCheckBox.setBounds(7, 7, 99, 23);
panel.add(ckbxTestCheckBox);
JRadioButton rdbtnTestRadioButton1 = new JRadioButton("Test Radio Button 1");
rdbtnTestRadioButton1.setBounds(7, 34, 121, 23);
panel.add(rdbtnTestRadioButton1);
JRadioButton rdbtnTestRadioButton2 = new JRadioButton("Test Radio Button 2");
rdbtnTestRadioButton2.setBounds(7, 61, 121, 23);
panel.add(rdbtnTestRadioButton2);
JRadioButton rdbtnTestRadioButton3 = new JRadioButton("Test Radio Button 3");
rdbtnTestRadioButton3.setBounds(7, 88, 121, 23);
panel.add(rdbtnTestRadioButton3);

JRadioButton rdbtnTest[] = {rdbtnTestRadioButton1, rdbtnTestRadioButton2, rdbtnTestRadioButton3};

ButtonGroup btnGrpTest = new ButtonGroup();
for(int i = 0; i < rdbtnTest.length; i++){
btnGrpTest.add(rdbtnTest[i]);
}

if(!ckbxTestCheckBox.isSelected()){
for(int i = 0; i < rdbtnTest.length; i++){
rdbtnTest[i].setEnabled(false);
rdbtnTest[i].setSelected(false);
}
} else { //Is this part even necessary?
for(int i = 0; i < rdbtnTest.length; i++){
rdbtnTest[i].setEnabled(true);
}
}
}
}

Answer

As @zubergu pointed out, your logic must be written inside an ItemListener for the checkbox , or it makes no sense.

Furthermore, your logic can be quite simplified without if and else blocks :

   ckbxTestCheckBox.addItemListener(new ItemListener() {
          public void itemStateChanged(ItemEvent e) {
                for(int i = 0; i < rdbtnTest.length; i++){

                    rdbtnTest[i].setEnabled(!ckbxTestCheckBox.isSelected());

                    if(!ckbxTestCheckBox.isSelected()) 
                       rdbtnTest[i].setSelected(false);
                }

          }
        });

Note that for JCheckBox, an ActionListener instead of an ItemListener, would also work.

Comments