Java Swing-空布局-如何为组件设置Z索引？

Question

I am trying to create a freecell game, I have not implemented the logic yet as I am having trouble with the layout.

The main issue that I have not been able to solve is that the JFrame orders cards Z index values in the order that they are painted, such that the first card painted has the highest Z-index.

I am trying to make the z index changeable.

I am using a null layout - the professors instructions said to not utilize any managers or external layout help. (ugh)

Attempted solutions:

I tried using JLayeredPane by instantiating a pane, setting its bounds to fit exactly in the JFrame, adding all my cards to the Layered pane, and then adding the pane to the JFrame - but that did not work.

I tried using the "setComponentZOrder(comp, index)" but that did not change the axis either.

Below is my code. Is there no way to do this on null layouts?

This oneDrive link contains the card images if you are attempting to run the program.

Images Download

Main:

import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.io.File;
import java.util.*;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class FreeCellGame extends JFrame implements MouseListener, MouseMotionListener
{
    public ArrayList<String> randomizedKeys = new ArrayList<String>();
    public HashMap<String, CardImagePanel> allCards;

    public static void main(String[] args)
    {
        FreeCellGame projectBoard = new FreeCellGame();
        projectBoard.allCards = new HashMap<String, CardImagePanel>();
        projectBoard.setSize(1218,800);
        projectBoard.setLayout(null);
        projectBoard.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        
        projectBoard.allCards = projectBoard.loadCardObjects(projectBoard.allCards);
        projectBoard = projectBoard.placeCardsOnBoard(projectBoard);
        projectBoard = addshapes(projectBoard);
        projectBoard.repaint();
        projectBoard.revalidate();
        projectBoard.setVisible(true);

    }

    private static FreeCellGame addshapes(FreeCellGame projectBoard) {

        int xPos = 0;
        int yPos = 50;

        JLabel foundations = new JLabel("Foundations");
        foundations.setBounds(790, 50, 300, 50);
        foundations.setFont(new Font("Courier New", Font.BOLD, 30));
        projectBoard.add(foundations);
        JLabel freeCells = new JLabel("Free Cells");
        freeCells.setBounds(210, 200, 300, 50);
        freeCells.setFont(new Font("Courier New", Font.BOLD, 30));
        projectBoard.add(freeCells);

        for(int i = 0;  i < 8; i++)
        {
            JPanel rect = new JPanel();
            rect.setBorder(BorderFactory.createLineBorder(Color.black));
            rect.setBounds(xPos, yPos, 150, 150);
            projectBoard.add(rect);
            xPos+=150;
            if(i == 3)
            {
                yPos = 100;
            }
        }
        return projectBoard;
    }

    private HashMap<String, CardImagePanel> loadCardObjects(HashMap<String, CardImagePanel> allCards)
    {
      File folder = new File("C:/Users/chris/Documents/GitHub/EclipseProjects/C585-FreeCell/src/images");
      File[] listOfFiles = folder.listFiles();
      allCards = new HashMap<String, CardImagePanel>();

      for (File file : listOfFiles) {
        if (file.isFile()) {
          String hashKey = file.getName();
          randomizedKeys.add(hashKey);
          CardImagePanel currentImage = new CardImagePanel(file);
          currentImage.setPreferredSize(new Dimension(157, 157));//5px on both sides as margin
          allCards.put(hashKey, currentImage);
          allCards.get(hashKey).addMouseListener(allCards.get(hashKey));
          allCards.get(hashKey).addMouseMotionListener(allCards.get(hashKey));
        }
      }
      Collections.shuffle(randomizedKeys);
      return allCards;
    }

    private FreeCellGame placeCardsOnBoard(FreeCellGame projectBoard)
    {
        int x = 0;
        int y = 540;
        int count = 0;
        for(String newRandomKey : randomizedKeys)
        {
            System.out.println(newRandomKey);
            if(count == 7 || count == 14 || count == 21)
            {
                x+=150;
                y=540;
            }
            else if( count == 28 || count == 34 || count == 40 || count == 46)
            {
                x+=150;
                y=500;
            }
            else if (count != 0)
            {
                y-=40;
            }
            allCards.get(newRandomKey).setBounds(x, y, 150, 150);
            projectBoard.add(allCards.get(newRandomKey));
            count++;
        }
        return projectBoard;
    }
    @Override
    public void mouseDragged(MouseEvent e) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseMoved(MouseEvent e) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseClicked(MouseEvent e) {
//      ((CardImagePanel) e.getSource()).setComponentZOrder(projectBoard, 5000);
    }
    @Override
    public void mouseEntered(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mousePressed(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseReleased(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }
 }

JPanel Class:

import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class CardImagePanel extends JPanel implements MouseListener, MouseMotionListener
{
    private BufferedImage picture;  
    private char cardType;
    private int cardNum;

    public CardImagePanel(File newImageFile)
    {
        try {
            picture = ImageIO.read(newImageFile);

        } catch (IOException e){
            e.printStackTrace();
        }
        cardType = newImageFile.getName().charAt(0);
        String tempString = newImageFile.getName();
        cardNum = Integer.parseInt(tempString.substring(1,tempString.lastIndexOf('.')));
    }

    public void paintComponent(Graphics g) {
      super.paintComponent(g);
      g.drawImage(picture, 0, 0, 150, 150, this);
    }

    public BufferedImage getPicture() {
        return picture;
    }
    public char getCardType() {
        return cardType;
    }
    public int getCardNum() {
        return cardNum;
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        this.setBounds(e.getX() + this.getX()-75, e.getY() + this.getY()-75, 150, 150);
    }
    @Override
    public void mouseMoved(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseClicked(MouseEvent e) {
    }
    @Override
    public void mouseEntered(MouseEvent e) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseExited(MouseEvent e) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mousePressed(MouseEvent e) {
        // TODO Auto-generated method stub
    }
    @Override
    public void mouseReleased(MouseEvent e) {
        // TODO Auto-generated method stub
    }
}

Answer 1

I am using a null layout - the professors instructions said to not utilize any managers or external layout help. (ugh)

So then basically you need to write your own layout manager.

Below is my code. Is there no way to do this on null layouts?

A null layout will have no effect on how Z-Ordering working. The Z-Ordering will be done for you automatically. The key is the order in which you add components to the panel so that you get the Z-Ordering you desire.

I am trying to make the z index changeable.

Adding components to a panel will affect the Z-Order.

Check out Overlap Layout which is a layout manager specifically designed for this. I know you can't use the layout manager, but better understanding how Z-Order works will allow you to write your code simply.

For example check out the simple code below. By simply playing with which add(...) method you use to add the cards to the panel you can control the Z-Order to your advantage:

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

public class SSCCE extends JPanel
{
    ArrayList<JLabel> cards = new ArrayList<JLabel>();

    public SSCCE()
    {
        setLayout( null );

        cards.add( createCard("1", Color.RED) );
        cards.add( createCard("2", Color.GREEN) );
        cards.add( createCard("3", Color.BLUE) );
        cards.add( createCard("4", Color.YELLOW) );

        //  This would be your first natural attempt (but it doesn't work)

        for (int i = 0; i < cards.size(); i++)
            add( cards.get(i) );

        //  This affects the Z-Order to do what you want

//      for (int i = 0; i < cards.size(); i++)
//          add(cards.get(i), 0);
    }

    public JLabel createCard(String text, Color background)
    {
        JLabel label = new JLabel(text);
        label.setOpaque( true );
        label.setBackground( background );
        label.setSize(30, 70);
        label.setLocation((cards.size() + 1) * 20 , 20);

        return label;
    }



    private static void createAndShowGUI()
    {
        JFrame frame = new JFrame("SSCCE");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add(new SSCCE());
        frame.setLocationByPlatform( true );
        frame.setSize(200, 200);
        frame.setVisible( true );
    }

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

Answer 2

I don't often support null layouts, I think there is such a small set of use-cases where the are really useful, however, you think this is one of those situations, then I would highly recommend the use of a JLayeredPane , as it will allow you to control the z-ordering of the components.

Have a look at How to Use Layered Panes for more details