How to prevent JPopUpMenu disappearing when checking checkboxes in it? - swing

Question

I want to use JCheckBoxMenuItems in a JPopupMenu. It works, but the problem is that the popup menu disappears when a checkbox item has been checked or unchecked. So if one wants to check/uncheck several items, the popup needs to be launched repeatedly, which is irritating.
Curiously, if I use just plain JCheckBox items in the menu (instead of JCheckBoxMenuItems), the behavior is just as it should be: the popup stays there and the checkboxes can be checked/unchecked. Once done, the popup can be closed just by clicking outside it.
How do I make the popup to behave like that when the items there are JCheckBoxMenuItems? I would prefer using JCheckBoxMenuItems because of their looks.

Answer 1

Well, found working answer from http://forums.sun.com/thread.jspa?threadID=5432911. Basically, create a custom UI:
public class StayOpenCheckBoxMenuItemUI extends BasicCheckBoxMenuItemUI {
#Override
protected void doClick(MenuSelectionManager msm) {
menuItem.doClick(0);
}
public static ComponentUI createUI(JComponent c) {
return new StayOpenCheckBoxMenuItemUI();
}
}
And set it in the JCheckBoxMenuItem:
myJCheckBoxMenuItem.setUI(new StayOpenCheckBoxMenuItemUI());
Don't know if this is the most elegant possible solution, but works perfectly.

Answer 2

I ran into an issue with the nice Joonas Pulakka's answer because the "UIManager lookandFeel" was ignored.
I found the nice trick below on http://tips4java.wordpress.com/2010/09/12/keeping-menus-open/
The point is to reopen immediatly the menu after it has been closed, it's invisible and keep the application look and feel and behavior.
public class StayOpenCBItem extends JCheckBoxMenuItem {
private static MenuElement[] path;
{
getModel().addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent e) {
if (getModel().isArmed() && isShowing()) {
path = MenuSelectionManager.defaultManager().getSelectedPath();
}
}
});
}
public StayOpenCBItem(String text) {
super(text);
}
#Override
public void doClick(int pressTime) {
super.doClick(pressTime);
MenuSelectionManager.defaultManager().setSelectedPath(path);
}
}

Answer 3

I found a much easier solution for this problem
JCheckBoxMenuItem menuItem = new JCheckBoxMenuItem("sample");
menuItem.putClientProperty("CheckBoxMenuItem.doNotCloseOnMouseClick", Boolean.TRUE);
I found this solution while reading the code from
BasicMenuItemUI.doNotCloseOnMouseClick()