Java Swing How to - Use getValue for JFormattedText to display in another JFormattedText field

Question

We would like to know how to use getValue for JFormattedText to display in another JFormattedText field.

Answer

import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFormattedTextField;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import java.awt.event.ActionEvent;
import java.text.DecimalFormat;
//from   w  w  w  . j  a  v  a  2  s.c o  m
public class Main extends JFrame {
  public static void main( String[] args ) {
    DecimalFormat format = new DecimalFormat( "####.##" );
    format.setMinimumFractionDigits( 2 );
    final JFormattedTextField field1 = new JFormattedTextField(
        format );
    final JFormattedTextField field2 = new JFormattedTextField(
        format );
    field1.setColumns( 15 );
    field2.setColumns( 15 );
    JButton btn = new JButton( new AbstractAction( "Multiply by 2" ) {

      @Override
      public void actionPerformed( ActionEvent e ) {
        Number value = ( Number ) field1.getValue();
        if ( value != null ){
          field2.setValue( 2 * value.doubleValue() );
        }
      }
    } );

    JPanel panel = new JPanel();
    panel.add( field1 );
    panel.add( btn );
    panel.add( field2 );
    JOptionPane.showMessageDialog( null, panel );
  }
}