在列表上显示弹出菜单

Question

我对弹出菜单有问题。我想要的是，当用户在jlist上单击鼠标右键时，会出现一个弹出菜单。我创建了一个类，在其中我创建了弹出菜单，一个扩展了mouselistener的类，以及另一个将鼠标侦听器添加到jlist的类。在扩展mouselistener的类中，我调用弹出菜单的类并显示它。问题是弹出菜单没有出现。

package mouseListener;

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.*;

import view.___poupupmenu___;

public class Add_popupmenu_categoria implements MouseListener 
{
   JList <String> l = new JList <String> ();

    public Add_popupmenu_categoria (JList <String> l)
{
    this.l = l;
}

public void mouseClicked(MouseEvent evt)
{
    System.out.println("clicked");

    if (evt.isPopupTrigger()) 
    {
        System.out.println("enter in clicked");

        ___poupupmenu___ p = new ___poupupmenu___();

        l.setSelectedIndex(l.locationToIndex(evt.getPoint()));
        System.out.println(evt.getComponent());
        l.setComponentPopupMenu(p.menu_categoria);
        p.menu_categoria.show(evt.getComponent(), evt.getX(), evt.getY());

    } 
}          


public void mouseEntered(MouseEvent e)
{

}

public void mouseExited(MouseEvent e)
{

}

public void mousePressed(MouseEvent evt)
{
    System.out.println("pressed");

    if (evt.isPopupTrigger()) 
    {
        System.out.println("enter in pressed");

        ___poupupmenu___ p = new ___poupupmenu___();

        l.setSelectedIndex(l.locationToIndex(evt.getPoint()));
        System.out.println(evt.getComponent());
        l.setComponentPopupMenu(p.menu_categoria);
        p.menu_categoria.show(evt.getComponent(), evt.getX(), evt.getY());

    } 
}

public void mouseReleased(MouseEvent evt)
{

    System.out.println("released");

    if (evt.isPopupTrigger()) 
    {
        System.out.println("enter in released");

        ___poupupmenu___ p = new ___poupupmenu___();

        l.setSelectedIndex(l.locationToIndex(evt.getPoint()));
        System.out.println(evt.getComponent());
        l.setComponentPopupMenu(p.menu_categoria);
        p.menu_categoria.show(evt.getComponent(), evt.getX(), evt.getY());


    } 
}
}



package view;

import javax.swing.*;

import java.awt.*;

public class ___poupupmenu___ {

public JPopupMenu menu_categoria = new JPopupMenu();
public JPopupMenu menu_scuola = new JPopupMenu();
public JPopupMenu menu_maschile_femminile = new JPopupMenu();
public JPopupMenu menu_dirigenti_allenatori = new JPopupMenu();
public JPopupMenu menu_img_profilo = new JPopupMenu();

JMenuItem menu_elimina = new JMenuItem("Elimina");
JMenuItem menu_modifica = new JMenuItem("Modifica");
JMenuItem menu_apri = new JMenuItem("Apri...");    
JMenuItem menu_pagamento = new JMenuItem("Visualizza pagamenti");
JMenuItem menu_genitore = new JMenuItem("Visualizza genitore");
JMenuItem menu_visita_medica = new JMenuItem("Visualizza scadenza visita medica");

  public ___poupupmenu___ ()
  {
       menu_elimina.setFont(new Font("Segoe UI", 1, 15)); 
       menu_modifica.setFont(new Font("Segoe UI", 1, 15)); 
       menu_apri.setFont(new Font("Segoe UI", 1, 15)); 
       menu_pagamento.setFont(new Font("Segoe UI", 1, 15));  
       menu_genitore.setFont(new Font("Segoe UI", 1, 15)); 

       menu_categoria.add(menu_modifica);
       menu_categoria.add(menu_elimina);

       menu_scuola.add(menu_apri);
       menu_scuola.add(menu_visita_medica);
       menu_scuola.add(menu_genitore);
       menu_scuola.add(menu_pagamento);
       menu_scuola.add(menu_modifica);
       menu_scuola.add(menu_pagamento);

       menu_maschile_femminile.add(menu_apri);
       menu_maschile_femminile.add(menu_visita_medica);
       menu_maschile_femminile.add(menu_modifica);
       menu_maschile_femminile.add(menu_elimina);

       menu_dirigenti_allenatori.add(menu_apri);
       menu_dirigenti_allenatori.add(menu_modifica);
       menu_dirigenti_allenatori.add(menu_elimina);

   }

}


package controller;

import javax.swing.*;

import mouseListener.Add_popupmenu_categoria;

public class CategoriaController 
{

   public void add_popupmenu_Categoria (JList <String> l)
   {
      Add_popupmenu_categoria apmc = new Add_popupmenu_categoria (l);
      l.addMouseListener(apmc);
   }
}

当我点击我得到的是：

在released javax中按released enter。摆动JList[，0,0897x797，alignmentX=0.0，alignmentY=0.0，border=，flags=50331944，maximumSize=，minimumSize=，preferredSize=，fixedCellHeight=-1，fixedCellWidth=-1，horizontalScrollIncrement=-1，selectionBackground=javax.swing.plaf.ColorUIResource[r=184，g=207，b=229]，SelectionForegrough=sun。摆动PrintColorUIResource[r=51，g=51，b=51]，visibleRowCount=8，layoutOrientation=0]点击

有人能帮我吗？

Answer 1

编辑：最简单的方法是只使用JList的setComponentPopupMenu方法：

JPopupMenu popup = new JPopupMenu();
popup.add(new JMenuItem("Hello World"));

JList<String> jList = new JList<String>();
jList.setComponentPopupMenu(popup);

setComponentPopupMenu（弹出）将弹出窗口附加到组件。如果右键单击组件，它将自动显示。不需要鼠标听器。

为swing组件实现弹出菜单的另一个简单方法是重写JComponent的getComponentPopupMenu（）方法。对你来说，解决方案是这样的：

public class MyJListWithPopupMenu extends JList {
    //...
    @Override
    public JPopupMenu getComponentPopupMenu() {
        // create your PopupMenu
        return myJPopupMenu;
    }
    //...
}

然后，当您使用MyjListWithPopup菜单而不是常规的JList时，右键单击弹出窗口时，它将显示在正确的位置。