如何监听 JCombobox 选择事件

【问题标题】：How to Listen for JCombobox Selection Event如何监听 JCombobox 选择事件
【发布时间】：2012-08-22 20:08:59
【问题描述】：

当我选择JCombobox 时，我想在它被选中并显示下拉列表时处理事件，以及在下拉列表消失和JCombobox 被取消选择时处理事件。

注意，我不是在寻找项目选择更改，而是在用户选择 JCombobox 并且 UI 弹出下拉菜单时。

【问题讨论】：

标签： java swing event-handling jcombobox jpopup

【解决方案1】：

您想使用addPopupMenuListener，它使用以下接口：

public interface PopupMenuListener extends EventListener {

    /**
     *  This method is called before the popup menu becomes visible 
     */
    void popupMenuWillBecomeVisible(PopupMenuEvent e);

    /**
     * This method is called before the popup menu becomes invisible
     * Note that a JPopupMenu can become invisible any time 
     */
    void popupMenuWillBecomeInvisible(PopupMenuEvent e);

    /**
     * This method is called when the popup menu is canceled
     */
    void popupMenuCanceled(PopupMenuEvent e);
}

【讨论】：