import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class FahrenheitGUIwithButton {
   private int WIDTH = 300;
   private int HEIGHT = 75;

   private JFrame frame;
   private JPanel panel;
   private JLabel inputLabel, outputLabel, resultLabel;
   private JTextField fahrenheit;
   private JButton convertButton;

   //-----------------------------------------------------------------
   //  Sets up the GUI.
   //-----------------------------------------------------------------
   public FahrenheitGUIwithButton(){
      frame = new JFrame ("Temperature Conversion");
      frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);

      inputLabel = new JLabel ("Enter Fahrenheit temperature:");
      outputLabel = new JLabel ("Temperature in Celcius: ");
      resultLabel = new JLabel ("---");
	  convertButton = new JButton ("Convert");
	  convertButton.setEnabled(true);
	  convertButton.addActionListener( new ButtonListener());
	  
      fahrenheit = new JTextField (5);
      fahrenheit.addActionListener (new TempListener());

      panel = new JPanel();
      panel.setPreferredSize (new Dimension(WIDTH, HEIGHT));
      panel.setBackground (Color.yellow);
      panel.add (inputLabel);
      panel.add (fahrenheit);
      panel.add (outputLabel);
      panel.add (resultLabel);
      panel.add (convertButton);

      frame.getContentPane().add (panel);
   }

   //-----------------------------------------------------------------
   //  Displays the primary application frame.
   //-----------------------------------------------------------------
   public void display(){
      frame.pack();
      frame.show();
   }

   //*****************************************************************
   //  Represents an action listener for the temperature input field.
   //*****************************************************************
   private class TempListener implements ActionListener {
      //--------------------------------------------------------------
      //  Performs the conversion when the enter key is pressed in
      //  the text field.
      //--------------------------------------------------------------
      public void actionPerformed (ActionEvent event) {
         int fahrenheitTemp, celciusTemp;

         String text = fahrenheit.getText();

         fahrenheitTemp = Integer.parseInt (text);
         celciusTemp = (fahrenheitTemp-32) * 5/9;

         resultLabel.setText (Integer.toString (celciusTemp));
      }
   }
  
   private class ButtonListener implements ActionListener {
   		public void actionPerformed (ActionEvent event) {
   			int fahrenheitTemp, celciusTemp;
   			String text = fahrenheit.getText();
   			
   			fahrenheitTemp = Integer.parseInt(text);
   			celciusTemp = (fahrenheitTemp - 32) * 5/9;
   			resultLabel.setText(Integer.toString(celciusTemp));
   		
   	in	}
   }
}