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();

}

}