java - JPopupMenu 的面积是否太小？

Question

在上一个问题中，我向社区询问为什么我的 JPopupMenu 没有出现在屏幕上。
我无法想出一个简单的、可运行的、可编译的示例。
所以，这就是我为你们所做的:

区域太小，无法绘制弹出窗口吗？

我希望我的弹出窗口是这样的:
我所做的代码在第一张照片中可见。

代码:

/* The old code entered here has been removed */

完整代码可以是found here

编辑2

我将各种 JRadioButtonMenuItem 和 setupJPopup() 复制到一个新文件中并运行。有用。为什么它在 ScreenRecorder 类中不起作用？代码封装演示；

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

import javax.swing.ButtonGroup;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuItem;
import javax.swing.JPopupMenu;
import javax.swing.JRadioButtonMenuItem;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class PopupTrial {


    public PopupTrial(){
        setupJPopup();
        JFrame frame = new JFrame();
        try{
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        }catch(Exception e){

        }
        frame.getContentPane().add(label);
        label.addMouseListener(new MouseAdapter(){
            @Override
            public void mouseClicked(MouseEvent e){
                popup.show(e.getComponent(), e.getX(), e.getY());
            }
        });
        frame.setVisible(true);
        frame.setSize(300, 300);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run(){
                new PopupTrial();
            }
        });
    }
    public void setupJPopup(){
        encodingGroup.add(avi);
        encodingGroup.add(quicktime);

        popup.add(avi);
        popup.add(quicktime);
        popup.addSeparator();

        recordingAreaGroup.add(entireScreen);
        recordingAreaGroup.add(custom);

        popup.add(entireScreen);
        popup.add(custom);
        popup.addSeparator();

        cursorGroup.add(selectBlackCursor);
        cursorGroup.add(selectWhiteCursor);
        cursorGroup.add(selectNoCursor);

        selectCursor.add(selectBlackCursor);
        selectCursor.add(selectWhiteCursor);
        selectCursor.add(selectNoCursor);

        popup.add(selectCursor);
        popup.pack();
    }
    JLabel label = new JLabel("Click Me");
    ButtonGroup recordingAreaGroup = new ButtonGroup();
    ButtonGroup cursorGroup = new ButtonGroup();
    ButtonGroup encodingGroup = new ButtonGroup();
    JPopupMenu popup = new JPopupMenu();
    JRadioButtonMenuItem avi = new JRadioButtonMenuItem("AVI",true);
    JRadioButtonMenuItem quicktime = new JRadioButtonMenuItem("QuickTime",false);
    JRadioButtonMenuItem entireScreen = new JRadioButtonMenuItem("Entire Screen",true);
    JRadioButtonMenuItem custom = new JRadioButtonMenuItem("Custom...",false);
    JMenuItem selectCursor = new JMenu("Select a cursor");
    JRadioButtonMenuItem selectWhiteCursor = new JRadioButtonMenuItem("White Cursor",true);
    JRadioButtonMenuItem selectBlackCursor = new JRadioButtonMenuItem("Black Cursor",false);
    JRadioButtonMenuItem selectNoCursor = new JRadioButtonMenuItem("No Cursor",false);
}

Answer 1

不，JFrame 的大小与 PopupMenu 不显示的原因无关。这是一个示例，显示与您想要的类似(并使用类似的方法)的工作:

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

public class PopupMenu extends Box{

    Dimension preferredSize = new Dimension(400,30);

    public PopupMenu(){
        super(BoxLayout.Y_AXIS);

        final JPopupMenu menu = new JPopupMenu("Options");
        for(int i = 1; i < 20; i++)
            menu.add(new JMenuItem("Option" + i));

        JLabel clickMe = new JLabel("ClickMe");
    clickMe.setAlignmentX(RIGHT_ALIGNMENT);
        clickMe.addMouseListener(new MouseAdapter(){

            @Override
            public void mouseClicked(MouseEvent e) {
                menu.show(e.getComponent(), e.getX(), e.getY());
            }});

        add(clickMe);       
    }

    public Dimension getPreferredSize(){
        return preferredSize;
    }

    public static void main(String[] args) {

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new PopupMenu());
        frame.validate();
        frame.pack();
        frame.setVisible(true);
    }
}