JCheckBoxes and item events. - Java Swing

Java examples for Swing:JCheckBox

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Description

JCheckBoxes and item events.

Demo Code

import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ItemListener;
import java.awt.event.ItemEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JCheckBox;

class CheckBoxFrame extends JFrame 
{
   private final JTextField textField; // displays text in changing fonts
   private final JCheckBox boldJCheckBox; // to select/deselect bold
   private final JCheckBox italicJCheckBox; // to select/deselect italic

   // CheckBoxFrame constructor adds JCheckBoxes to JFrame
   public CheckBoxFrame()
   {//from w  ww.  j av  a  2s.  c  o m
      super("JCheckBox Test");
      setLayout(new FlowLayout());

      // set up JTextField and set its font
      textField = new JTextField("Watch the font style change", 20);
      textField.setFont(new Font("Serif", Font.PLAIN, 14));
      add(textField); // add textField to JFrame

      boldJCheckBox = new JCheckBox("Bold"); 
      italicJCheckBox = new JCheckBox("Italic"); 
      add(boldJCheckBox); // add bold checkbox to JFrame
      add(italicJCheckBox); // add italic checkbox to JFrame

      // register listeners for JCheckBoxes
      CheckBoxHandler handler = new CheckBoxHandler();
      boldJCheckBox.addItemListener(handler);
      italicJCheckBox.addItemListener(handler);
   } 

   // private inner class for ItemListener event handling
   private class CheckBoxHandler implements ItemListener 
   {
      // respond to checkbox events
      @Override
      public void itemStateChanged(ItemEvent event)
      {
         Font font = null; // stores the new Font

         // determine which CheckBoxes are checked and create Font
         if (boldJCheckBox.isSelected() && italicJCheckBox.isSelected())
            font = new Font("Serif", Font.BOLD + Font.ITALIC, 14);
         else if (boldJCheckBox.isSelected())
            font = new Font("Serif", Font.BOLD, 14);
         else if (italicJCheckBox.isSelected())
            font = new Font("Serif", Font.ITALIC, 14);
         else
            font = new Font("Serif", Font.PLAIN, 14);

         textField.setFont(font); 
      } 
   }
}

public class Main
{
   public static void main(String[] args)
   { 
      CheckBoxFrame checkBoxFrame = new CheckBoxFrame(); 
      checkBoxFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      checkBoxFrame.setSize(275, 100); 
      checkBoxFrame.setVisible(true); 
   } 
}

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