Java：在绘制主画布的类之外使用 Graphics 进行绘制

Question

我正在尝试使用图形在 Java 中开发井字游戏。 我的问题是：我不想在我的 Grid.class 中添加任何其他方法（绘制线 3x3），但我想从名为 Game 的类中绘制我的 X 或 O。我的网格类如下所示：

import java.awt.Graphics;
import javax.swing.JPanel;

public class Grid extends JPanel{

    private final int ITEM_WIDTH = 30;
    private final int ITEM_HEIGHT = 30;
    private final int OUTER_WIDTH = 90;
private final int OUTER_HEIGHT = 90;

public void paintComponent(Graphics g){
    super.paintComponent(g);
    drawOuter(g);
    drawGrid(g);
}

public void drawOuter(Graphics g){
    g.drawRect(0, 0, OUTER_WIDTH, OUTER_HEIGHT);
}

public void drawGrid(Graphics g){
    //Vertikális
    for(int i = ITEM_WIDTH; i < OUTER_WIDTH; i += ITEM_WIDTH){
        g.drawLine(i, 0, i, OUTER_HEIGHT);
    }
    //Horizontális
    for(int i = ITEM_HEIGHT; i < OUTER_HEIGHT; i += ITEM_HEIGHT){
        g.drawLine(0, i, OUTER_WIDTH, i);
    }
}

感谢您的帮助

Answer 1

我的建议是尽量让事情尽可能简单。

• 创建包含 X 和 O 图像的 ImageIcons
• 在上面的 JPanel 中放置一个 JLabels 的 GridLayout。
• 当我想显示 X、O 或空白时交换 JLabel 的 ImageIcon。

概念验证代码。多次单击 JLabels 将显示图标。该代码虽然没有井字游戏逻辑：

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;

import javax.swing.*;

@SuppressWarnings("serial")
public class XorOorBlank extends JPanel {
   private static final int IMG_WIDTH = 100;
   private static final Color BACKGROUND = Color.LIGHT_GRAY;
   private static final Color X_COLOR = Color.red;
   private static final Color O_COLOR = Color.blue;
   private static final Stroke X_STROKE = new BasicStroke(8f);
   private static final int GAP = 8;
   private static final int SIDE = 3;
   private Icon blankIcon = createBlankIcon();
   private Icon xIcon = createXIcon();
   private Icon oIcon = createOIcon();

   public XorOorBlank() {
      setBackground(BACKGROUND);
      setLayout(new GridLayout(SIDE, SIDE, GAP, GAP));

      MouseListener mouseListener = new MouseAdapter() {
         @Override
         public void mousePressed(MouseEvent e) {
            JLabel label = (JLabel) e.getSource();
            Icon icon = label.getIcon();
            if (icon == blankIcon) {
               icon = xIcon;
            } else if (icon == xIcon) {
               icon = oIcon;
            } else if (icon == oIcon) {
               icon = blankIcon;
            }
            label.setIcon(icon);
         }
      };
      for (int i = 0; i < SIDE; i++) {
         for (int j = 0; j < SIDE; j++) {
            JLabel label = new JLabel(blankIcon);
            label.addMouseListener(mouseListener);
            add(label);
         }
      }
   }

   private Icon createBlankIcon() {
      BufferedImage img = new BufferedImage(IMG_WIDTH, IMG_WIDTH,
            BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2 = img.createGraphics();
      g2.setColor(Color.white);
      g2.fillRect(0, 0, IMG_WIDTH, IMG_WIDTH);
      g2.dispose();
      ImageIcon icon = new ImageIcon(img);
      return icon;
   }

   private Icon createXIcon() {
      BufferedImage img = new BufferedImage(IMG_WIDTH, IMG_WIDTH,
            BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2 = img.createGraphics();
      g2.setColor(Color.white);
      g2.fillRect(0, 0, IMG_WIDTH, IMG_WIDTH);
      g2.setColor(X_COLOR);
      g2.setStroke(X_STROKE);
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
      int x1 = GAP;
      int y1 = x1;
      int x2 = IMG_WIDTH - GAP;
      int y2 = x2;
      g2.drawLine(x1, y1, x2, y2);
      g2.drawLine(x2, y1, x1, y2);
      g2.dispose();
      ImageIcon icon = new ImageIcon(img);
      return icon;
   }

   private Icon createOIcon() {
      BufferedImage img = new BufferedImage(IMG_WIDTH, IMG_WIDTH,
            BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2 = img.createGraphics();
      g2.setColor(Color.white);
      g2.fillRect(0, 0, IMG_WIDTH, IMG_WIDTH);
      g2.setColor(O_COLOR);
      g2.setStroke(X_STROKE);
      g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);
      int x1 = GAP;
      int y1 = x1;
      int x2 = IMG_WIDTH - 2 * GAP;
      int y2 = x2;
      g2.drawOval(x1, y1, x2, y2);
      g2.dispose();
      ImageIcon icon = new ImageIcon(img);
      return icon;
   }

   private static void createAndShowGui() {
      JFrame frame = new JFrame("X or O");
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.getContentPane().add(new XorOorBlank());
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

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

注意：不是paintComponent方法。

这显示：

Answer 2

你有几个选择...

你可以

从Grid 扩展，覆盖它的paintComponent 方法并在其中绘制X/Os（调用super.paintComponent）

你可以

创建一个interface，它提供了一个简单的“绘制”方法，当实现该方法时，将绘制X/O。然后，您可以简单地将 this 的新实例添加到 Grid 类，并让它通过 paintComponent 方法中的某种循环绘制 X/O

你可以

使用GridBagLayout 甚至OverlayLayout 之类的东西并将另一个面板放在Grid 类的顶部，或者，使用BorderLayout，将面板直接添加到Grid 类，然后负责画X/O

你可以

按照 Hovercraft Full Of Eels 的建议去做...