AbstractAction -- JButton

Question

class QueryAction extends AbstractAction
// Constructor
QueryAction(String name)
super(name);
String iconFileName = "Images/" + name + ".gif";
if(new File(iconFileName).exists())
putValue(SMALL_ICON, new ImageIcon(iconFileName));
public void aFunc(){
QueryAction anAction = new QueryAction("Compile Query");
JButton button = new JButton(anAction);
toolBar.add(button);
in other function, I'm trying to disable the button with that particular description string (i.e. "Compile Query"):
Component[] comp = toolBar.getComponents();
for (int i=0; i<comp.length; i++){
JButton aButton = (JButton)comp;
Action act = aButton.getAction();
if(act.getValue(Action.NAME).equals("Compile Query"));
aButton.setEnable(false);
break;
But I got NullPointerException for the statement :
act.getValue(Action.NAME)
Anybody has an idea how to solve this...?? thx

Answer 1

Seems to me that your toolBar contains a button which has no action assigned to it.
Try this: keep a reference to your QueryAction in your class and disable it instead of the button (this feature is one of the reason to use actions afterall):
public class XYPanel {
  private QueryAction queryAction = new QueryAction();
  private class QueryAction {
    public QueryAction() {
      super("Compile Query");
    // how about using a class resource instead of a file
    // - better for using jars in your app
    putValue(SMALL_ICON, new ImageIcon(getClass().getResource("query.gif")));  
  public void aFunc() {
    toolBar.add(queryAction);
  public void anotherFunc()
    queryAction.setEnabled(false);