Question

I want the content of the combo box updates with the corresponding radiobutton, how can I write the two radioButton actionListeners? and mycomboBox addItemListener?

There are 4 GUI components at the top (NORTH) of the ContentPane of the JFrame, label, two radio buttons, and a combo box. The combo box is empty. When a user has clicked a radio button, the content of the combo box will be update You will need to use the setModel method and set the corresponding DefaultComboBoxModel to the combo box. See the screenshots below. A2 X A2 Testing ABC 123 1 Testing ABC 123 A 1 A 2 When the user has selected an item in the combo box, the JLabel will be updated by the selected item. X X A2 A2 123 C CO ABC 20 ABC O 123 2 Steps: BCOE import javax.swing. * import iavaawt.* import iava awt.event import javax. swing. border.* import javax. swing. event. * import java.util. * public class A2Help01 extends JFrame private JComboBox my.camboBax DefaultComboBoxModel srcModel, destModel; private JRadioBut ton radioButtonABC, radioButton 123; /** main method for A2 */ public static void main (String [] args) i.avaxiswing Swinautilitiesinv.okelater.(new Runnable() public void run() new A2HelpQ1 ); } public A2HelpQ1 () ( super("A2"); setupRadioButtons (); getContentPane().add (setUpTo ol sPan el ( ), BorderLayout .NORTH); setDefaultClose0peration (JFrame. EXIT ON CLOSE); setSize(800, 500); setVisible(true); String labe ls1[]= "A", "B" s rcModel new DefaultComboBoxModel(labels1); String labels2[] = "1", "2" , "3", "4" , "5"; des tMode "C". "E" } ; "D" = new DefaultCombo BoxM ode l (labels2 ) ; private void setupRadio Buttons () radioButtonABC = new JRadioButton ( "ABC"): radioButton 123 = new JRadioButton("123" ) ; / add a ButtonGroup radioButtonABC. addAction Listener (new ActionListener ) ( public void actionPerformed (Action Event e) ( //Complete this radioButton123.addAction Listener(new ActionListener() public void actionPerformed (Action Event e) ( //complete this public JPansl setUpToolsPanel() nyCanboBax= new JComboBox (); nySamboBox.addItemkistener.(new ItemListener() ( 1/complete this JPanel toolsPanel toolsPanel. setLayout (new BoxLayout (tools Panel, BoxLayout.X_AXIS)); toolsPanel.add(radioButtonABC): toolsPanel.add(radioButton 12 3): toolsPanel.add(my.comboBax): return toolsPanel; =new Pans10;

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// A2HelpQ1.java

import java.awt.BorderLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.ItemEvent;

import java.awt.event.ItemListener;

import javax.swing.BoxLayout;

import javax.swing.ButtonGroup;

import javax.swing.DefaultComboBoxModel;

import javax.swing.JComboBox;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.JRadioButton;

public class A2HelpQ1 extends JFrame {

      private JComboBox<String> mycomboBox;

      DefaultComboBoxModel<String> srcModel, destModel;

      private JRadioButton radioButtonABC, radioButton123;

      // label for displaying selected value

      private JLabel label;

      public static void main(String[] args) {

            javax.swing.SwingUtilities.invokeLater(new Runnable() {

                  @Override

                  public void run() {

                        new A2HelpQ1();

                  }

            });

      }

      public A2HelpQ1() {

            super("A2");

            setupRadioButtons();

            getContentPane().add(setupToolsPanel(), BorderLayout.NORTH);

            setDefaultCloseOperation(EXIT_ON_CLOSE);

            setSize(800, 500);

            setVisible(true);

            String labels1[] = { "A", "B", "C", "D", "E" };

            srcModel = new DefaultComboBoxModel<String>(labels1);

            String labels2[] = { "1", "2", "3", "4", "5" };

            destModel = new DefaultComboBoxModel<String>(labels2);

      }

      private void setupRadioButtons() {

            radioButtonABC = new JRadioButton("ABC");

            radioButton123 = new JRadioButton("123");

            // creating a ButtonGroup, adding radio buttons to it, so that only one

            // can be selected at a time

            ButtonGroup group = new ButtonGroup();

            group.add(radioButtonABC);

            group.add(radioButton123);

            radioButtonABC.addActionListener(new ActionListener() {

                  public void actionPerformed(ActionEvent arg0) {

                        // setting model of mycomboBox to srcModel

                        mycomboBox.setModel(srcModel);

                  }

            });

            radioButton123.addActionListener(new ActionListener() {

                  public void actionPerformed(ActionEvent arg0) {

                        // setting model of mycomboBox to destModel

                        mycomboBox.setModel(destModel);

                  }

            });

      }

      public JPanel setupToolsPanel() {

            mycomboBox = new JComboBox<String>();

            mycomboBox.addItemListener(new ItemListener() {

                  public void itemStateChanged(ItemEvent arg0) {

                        // getting selected text from mycomboBox and setting it on label

                        label.setText(mycomboBox.getSelectedItem().toString());

                  }

            });

            //initializing label for displaying selected value

            label = new JLabel("Testing");

            JPanel toolsPanel = new JPanel();

            toolsPanel.setLayout(new BoxLayout(toolsPanel, BoxLayout.X_AXIS));

            toolsPanel.add(label); //adding label

            toolsPanel.add(radioButtonABC);

            toolsPanel.add(radioButton123);

            toolsPanel.add(mycomboBox);

            return toolsPanel;

      }

}

/*OUTPUT*/

X A2 Testing ABC 123

X A2 Testing ABC 123 A

X A2 Testing ABC O 123 1 1 3 4 5

X A2 ABC O 123 3 3