import org.eclipse.swt.SWT;
import org.eclipse.swt.events.VerifyEvent;
import org.eclipse.swt.events.VerifyListener;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
public class MainClass {
public static void main(String[] a) {
Display display = new Display();
// Create the main window
Shell shell = new Shell(display);
Text fahrenheit = new Text(shell, SWT.BORDER);
fahrenheit.setData("Type a temperature in Fahrenheit");
fahrenheit.setBounds(20, 20, 100, 20);
fahrenheit.addVerifyListener(new VerifyListener() {
public void verifyText(VerifyEvent event) {
// Assume we don't allow it
event.doit = false;
// Get the character typed
char myChar = event.character;
String text = ((Text) event.widget).getText();
// Allow '-' if first character
if (myChar == '-' && text.length() == 0)
event.doit = true;
// Allow 0-9
if (Character.isDigit(myChar))
event.doit = true;
// Allow backspace
if (myChar == '\b')
event.doit = true;
}
});
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
display.dispose();
}
}