Temperature Converter

[David Coello]

Hello forum members,

I am a new java developer. I have been working on a Converter from Farenheit to Celsius with the push of a button. I programmed it under those specs, but I would like to program that same button to convert back to celsius. I appreciate your comments, basically if a button can perform 2 actions, convert from Fahrenheit to Celsius and Celsius to Farenheit.


Thank you.

David

import java.awt.*;
import java.awt.event.*;

public class TempConverter 
{
	public static void main(String[] args) 
	{
    	Frame frame = new TempConverterFrame("Temperature Converter");
    	frame.setSize(167, 115);
    	frame.setVisible(true);
  	}
}
class TempConverterFrame extends Frame 
{
	private TextField fahrenField = new TextField();
	private TextField celsiusField = new TextField();
    public TempConverterFrame(String title) 
	{
    	super(title);

    	Panel top = new Panel(new GridLayout(2, 2));
    	top.add(new Label("Fahrenheit"));
    	top.add(fahrenField);
    	top.add(new Label("Celsius"));
    	top.add(celsiusField);
    	add("Center", top);
    	Panel bottom = new Panel();
    	Button b = new Button("Convert");
    	b.addActionListener(new ConvertListener());
    	bottom.add(b);
    	add("South", bottom);
    	addWindowListener(new WindowCloser());
  	}
	class ConvertListener implements ActionListener 
	{
    	public void actionPerformed(ActionEvent evt) 
		{
      		String fahrenheitString = fahrenField.getText();
      		double fahrenheit = Double.valueOf(fahrenheitString);
      		double celsius = (fahrenheit - 32.0) * 5.0 / 9.0;
			celsius = Math.rint(celsius * 100.0) / 100.0;
      		celsiusField.setText(celsius + "");
    	}
	}
	class WindowCloser extends WindowAdapter 
	{
    	public void windowClosing(WindowEvent evt) 
		{
    		System.exit(0);
    	}
  	}
}

[Jeanne Boyarsky]

Yes, the same button can do two things. You'd need an instance variable to remember which state the button is in so you know which label to display and which action to perform.

[Michael Dunn]

check which textfield is empty, via .equals(""), ensuring both are not empty,
then convert the non-empty for display in the empty