java – 为什么没有为我的JPopupMenu调用componentHidden？

我希望在我的JPopupMenu被隐藏时收到通知 – 无论是因为某个项目被选中,菜单被解除,还是被调用了setVisible(false).这是我的测试代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class A extends ComponentAdapter implements Runnable, ActionListener {
    private JButton b;

    public static void main(String[] args) {
        EventQueue.invokeLater(new A());
    }

    public void run() {
        JFrame f = new JFrame("Test");
        b = new JButton("Click me");
        b.addActionListener(this);
        f.add(b);
        f.pack();
        f.setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        JPopupMenu pm = new JPopupMenu();
        pm.addComponentListener(this);
        pm.add("Popup...");
        pm.add("...menu!");
        pm.show(b, 10, 10);
    }

    public void componentShown(ComponentEvent e) { System.out.println("componentShown"); }
    public void componentHidden(ComponentEvent e) { System.out.println("componentHidden"); }
}

无论我如何与菜单交互,都没有调用两个ComponentListener方法.这是为什么？当我的JPopupMenu被隐藏时,是否有不同/更好/正确的方法来查找？

谢谢,

卡梅伦

解决方法:

pm.addPopupMenuListener(new PopupMenuListener() {

    @Override
    public void popupMenuCanceled(PopupMenuEvent e) {
        System.out.println("cancelled");
    }

    @Override
    public void popupMenuWillBecomeInvisible(PopupMenuEvent e) {
        System.out.println("vanishing");
    }

    @Override
    public void popupMenuWillBecomeVisible(PopupMenuEvent e) {
        System.out.println("appearing");
    }
});

编辑：哎呀,看起来有人选择在评论中回答.我的错.

编辑2：关于为什么ComponentListener没有发送菜单上的事件消失,这可能解释为：

The component-hidden and component-shown events occur only as the result of calls to a Component ‘s setVisible method. For example, a window might be miniaturized into an icon (iconified) without a component-hidden event being fired.

资料来源：ComponentListener tutorial(也许是非规范的,但是来自马的嘴.)

考虑到结合JPopupMenu的setVisible实现：

    public void setVisible(boolean b) {
        // Not supported for MenuComponents
    }

你可能知道它是如何发生的,但不是为什么它会发生(理由是什么,哪里有正确记录？)

标签：java,swing,jpopupmenu
来源： https://codeday.me/bug/20190621/1258186.html