Question

我正在尝试为文件浏览器制作一组导航按钮。我想要它，以便如果用户单击专用历史记录按钮，则会出现JPopupMenu。但是，当用户右键单击或向下拖动光标向后或向前按钮时，我还希望显示完全相同的菜单。 如何针对不同的手势为多个GUI组件显示完全相同的JPopupMenu（不是副本，但是相同的副本）？

到目前为止，我已经尝试了以下内容：

histButton.addMouseListener(new MouseAdapter()
{
  @Override public void mouseClicked(MouseEvent e)
  {
    showPopup(e);
  }

  @Override public void mouseDragged(MouseEvent e)
  {
    showPopup(e);
  }

  private void showPopup(MouseEvent e)
  {
    histPopupMenu.show(e.getComponent(), e.getX(), e.getY());
  }
});
forwardButton.addMouseListener(new MouseAdapter()
{
  @Override public void mouseClicked(MouseEvent e)
  {
    if (e.isPopupTrigger())
      showPopup(e);
  }

  @Override public void mouseDragged(MouseEvent e)
  {
    showPopup(e);
  }

  private void showPopup(MouseEvent e)
  {
    histPopupMenu.show(e.getComponent(), e.getX(), e.getY());
  }
});
backButton.addMouseListener(new MouseAdapter()
{
  @Override public void mouseClicked(MouseEvent e)
  {
    if (e.isPopupTrigger())
      showPopup(e);
  }

  @Override public void mouseDragged(MouseEvent e)
  {
    showPopup(e);
  }

  private void showPopup(MouseEvent e)
  {
    histPopupMenu.show(e.getComponent(), e.getX(), e.getY());
  }
});

所有组件都已添加并正确显示，调试显示他们注册了事件，但没有显示任何菜单。

Answer 1

Bringing Up a Popup Menu显示了使用mousePressed()，mouseReleased()和isPopupTrigger()的传统实现。请注意“应该显示弹出菜单的确切手势因外观而异。”您可以将显示的内容与使用mousePressed()的实现进行比较。

附录：作为参考，@ mKorbel回忆起可能有用的client property。

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

/** @author mKorbel */
public class ComboBoxAction extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    private JComboBox comboBox;
    private JFrame frame;

    public ComboBoxAction() {
        comboBox = new JComboBox();
        comboBox.addActionListener(this);
        comboBox.addItem("Item 1");
        comboBox.addItem("Item 2");
        comboBox.addItem("Item 3");
        comboBox.addItem("Item 4");
        for (Component component : comboBox.getComponents()) {
            if (component instanceof AbstractButton) {
                if (component.isVisible()) {
                    comboBox.remove(component);
                }
            }
        }
        //This prevents action events from being fired when the
        //up/down arrow keys are used on the dropdown menu
        comboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);
        comboBox.firePopupMenuWillBecomeVisible();
        frame = new JFrame();
        frame.add(comboBox);
        frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        System.out.println(comboBox.getSelectedItem());
        //make sure popup is closed when 'isTableCellEditor' is used
        comboBox.hidePopup();
    }

    public static void main(String[] args) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ComboBoxAction();
            }
        });
    }
}

如果单击，右键单击或拖动3个JButton中的任何一个，如何显示JPopupMenu？

1 个答案: