测试代码如下：
复制代码 代码如下:
package swt_jface.demo;
import org.eclipse.jface.window.ApplicationWindow;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.ModifyEvent;
import org.eclipse.swt.events.ModifyListener;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Text;
public class TemperatureConverterJFace extends ApplicationWindow {
Label fahrenheitLabel;
Label celsiusLabel;
Text fahrenheitValue;
Text celsiusValue;

public TemperatureConverterJFace() {

super(null);

addStatusLine();
}
protected Control createContents(Composite parent) {
getShell().setText("JFace Temperature Converter");

Composite converterComposite = new Composite(parent, SWT.NULL);

converterComposite.setLayout(new GridLayout(4, false));
fahrenheitLabel = new Label(converterComposite, SWT.NULL);
fahrenheitLabel.setText("Fahrenheit: ");
fahrenheitValue = new Text(converterComposite, SWT.SINGLE | SWT.BORDER);
celsiusLabel = new Label(converterComposite, SWT.NULL);
celsiusLabel.setText("Celsius: ");
celsiusValue = new Text(converterComposite, SWT.SINGLE | SWT.BORDER);
ModifyListener listener = new ModifyListener() {
public void modifyText(ModifyEvent e) {
valueChanged((Text) e.widget);
}
};
fahrenheitValue.addModifyListener(listener);
celsiusValue.addModifyListener(listener);

return converterComposite;
}
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);
setStatus("Conversion performed successfully.");
} catch (NumberFormatException e) {
celsiusValue.setText("");
setStatus("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);
setStatus("Conversion performed successfully.");
} catch (NumberFormatException e) {
fahrenheitValue.setText("");
setStatus("Invalid number format: " + text.getText());
}
}
}

public static void main(String[] args) {
TemperatureConverterJFace converter = new TemperatureConverterJFace();
converter.setBlockOnOpen(true);
converter.open();
Display.getCurrent().dispose();
}
}

不使用ApplicationWindow（即只是用SWT类）的解决方案：
复制代码 代码如下:
package swt_jface.demo;
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();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
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();
}
}