eclipse下的简单计算器

package mycalculation;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.KeyAdapter;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import com.swtdesigner.SWTResourceManager;

public class simplecalculation {

private Text text;
public boolean add,sub,div,mul,end;
public String str;
public double num1,num2;
/**
 * Launch the application
 * @param args
 */
public static void main(String[] args) {
try {
simplecalculation window = new simplecalculation();
window.open();
} catch (Exception e) {
e.printStackTrace();
}

}

/**
 * Open the window
 */
public void open() {
end=true;
add=false;
sub=false;
div=false;
mul=false;
final Display display = Display.getDefault();
final Shell shell = new Shell();
shell.addKeyListener(new KeyAdapter() {
public void keyPressed(KeyEvent e) {
//当键盘点击时刻
}
});
shell.setBackground(SWTResourceManager.getColor(255, 255, 128));
shell.setSize(321, 285);
shell.setText("简单计算器");
//

shell.open();

text = new Text(shell, SWT.BORDER | SWT.RIGHT);
text.setText("0");
text.setBounds(26, 10, 262, 25);

final Button button = new Button(shell, SWT.NONE);