How to prevent JMenuItem from closing Menu upon clicking the JMenuItem

问题

How do I prevent a JMenuItem from closing the menu when the JMenuItem is clicked?

The JMenuItem is enabled.

So this is the scenario, I have 3 JMenuItems:

JMenuItem: A, B, C;

C displays an integer X.

A and B are used to increment or decrement X by a value of 1. If A or B is clicked, the default nature is that the menu will close upon click. I want to be able to repeatedly click A or B and have the menu remain up, and perform the associated 'action' upon each click.

Thanks!

回答1:

First, using a menu to do this may be the wrong approach. JSpinner seems more appropriate. However, to do this with a JMenuItem you can subclass the MenuItemUI of the LookAndFeel you are using, and override the doClick(...) method so that clearSelectionPath() is not called, which closes the menu when the item is clicked.

Example, if you are using the Motif LookAndFeel you can do this:

menuItem.setUI(new MotifMenuItemUI() {
    @Override
    protected void doClick(MenuSelectionManager msm) {
        menuItem.doClick(0);
    }
});

I haven't ever tried this myself but I think it will work.

来源：https://stackoverflow.com/questions/9198530/how-to-prevent-jmenuitem-from-closing-menu-upon-clicking-the-jmenuitem