TemperatureConverter.java Source code

Introduction

Here is the source code for TemperatureConverter.java

Source

/******************************************************************************
 * Copyright (c) 1998, 2004 Jackwind Li Guojie
 * All right reserved. 
 * 
 * Created on Jan 16, 2004 1:23:25 AM by JACK
 * $Id$
 * 
 * visit: http://www.asprise.com/swt
 *****************************************************************************/

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

public class TemperatureConverter {
    Display display = new Display();
    Shell shell = new Shell(display);

    Label fahrenheitLabel;
    Label celsiusLabel;
    Label messageLabel;

    Text fahrenheitValue;
    Text celsiusValue;

    public TemperatureConverter() {
        shell.setText("SWT Temperature Converter");
        shell.setLayout(new GridLayout(4, false));

        fahrenheitLabel = new Label(shell, SWT.NULL);
        fahrenheitLabel.setText("Fahrenheit: ");

        fahrenheitValue = new Text(shell, SWT.SINGLE | SWT.BORDER);

        celsiusLabel = new Label(shell, SWT.NULL);
        celsiusLabel.setText("Celsius: ");

        celsiusValue = new Text(shell, SWT.SINGLE | SWT.BORDER);

        messageLabel = new Label(shell, SWT.BORDER);
        GridData gridData = new GridData(GridData.FILL_BOTH);
        gridData.horizontalSpan = 4;
        messageLabel.setLayoutData(gridData);

        ModifyListener listener = new ModifyListener() {
            public void modifyText(ModifyEvent e) {
                valueChanged((Text) e.widget);
            }
        };

        fahrenheitValue.addModifyListener(listener);
        celsiusValue.addModifyListener(listener);

        shell.pack();
        shell.open();

        // Set up the event loop.
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                // If no more entries in event queue
                display.sleep();
            }
        }

        display.dispose();
    }

    /**
     * Performs conversion when one of the text fields changes.
     * 
     * @param text
     *            the event source
     */
    public void valueChanged(Text text) {
        if (!text.isFocusControl())
            return;

        if (text == fahrenheitValue) {
            try {
                double fValue = Double.parseDouble(text.getText());
                double cValue = (fValue - 32) / 1.8;
                celsiusValue.setText(Double.toString(cValue));
                System.out.println("F -> C: " + cValue);
                messageLabel.setText("Conversion performed successfully.");
            } catch (NumberFormatException e) {
                celsiusValue.setText("");
                messageLabel.setText("Invalid number format: " + text.getText());
            }
        } else {
            try {
                double cValue = Double.parseDouble(text.getText());
                double fValue = cValue * 1.8 + 32;
                fahrenheitValue.setText(Double.toString(fValue));
                System.out.println("C -> F: " + fValue);
                messageLabel.setText("Conversion performed successfully.");
            } catch (NumberFormatException e) {
                fahrenheitValue.setText("");
                messageLabel.setText("Invalid number format: " + text.getText());
            }
        }
    }

    public static void main(String[] args) {
        new TemperatureConverter();
    }
}