Java Swing图形实时渲染与交互：Polygon拖动动画优化教程

public void mouseDragged(MouseEvent e) {
    // 检查 currPolygon 是否已初始化，避免 NullPointerException
    if (currPolygon == null) {
        return;
    }

    // 只有当鼠标在当前多边形内部按下并拖动时才进行移动
    // 注意：这里的 x, y 是鼠标按下时的坐标，应与 currPolygon.contains(e.getPoint()) 配合
    // 或者更准确地，是检查 currPolygon.contains(按下时的点)
    // 但为了保持原逻辑，我们假设 x, y 记录的是上一次拖动事件的鼠标位置
    if (currPolygon.contains(x, y)) { // 实际上这里应该检查 currPolygon.contains(e.getX(), e.getY())
                                    // 或在 mousePressed 中确认 currPolygon 是否包含点击点
        System.out.println("Dragged");
        int dx = e.getX() - x;
        int dy = e.getY() - y;
        currPolygon.translate(dx, dy); // 移动多边形
        x = e.getX(); // 更新鼠标位置，为下一次拖动做准备
        y = e.getY(); // 更新鼠标位置
        shapePane.repaint(); // 关键：在绘制图形的 JPanel 上调用 repaint()
    }
}

// PentominoDrawingPanel.java
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List;

// 不再继承 JFrame，而是继承 JPanel
public class PentominoDrawingPanel extends JPanel implements MouseListener, MouseMotionListener {
    private List<CustomPolygonShape> shapes = new ArrayList<>(); // 使用自定义图形对象列表
    private CustomPolygonShape currShape; // 当前被拖动的图形
    private int mousePressX, mousePressY; // 鼠标按下时的坐标

    public PentominoDrawingPanel() {
        initShapes();
        // 添加鼠标监听器到当前 JPanel
        addMouseListener(this);
        addMouseMotionListener(this);
    }

    private void initShapes() {
        // 定义并初始化所有多边形和颜色，然后创建 CustomPolygonShape 实例
        // 示例：
        Polygon fig1 = new Polygon(new int[]{10, 50, 50, 10}, new int[]{10, 10, 200, 200}, 4);
        shapes.add(new CustomPolygonShape(fig1, new Color(25, 165, 25)));

        Polygon fig2 = new Polygon(new int[]{130, 210, 210, 170, 170, 130, 130, 90, 90, 130}, new int[]{80, 80, 120, 120, 200, 200, 160, 160, 120, 120}, 10);
        shapes.add(new CustomPolygonShape(fig2, new Color(255, 165, 25)));
        // ... 添加所有其他图形
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g); // 调用父类方法清空背景
        Graphics2D g2 = (Graphics2D) g;

        // 遍历所有自定义图形对象并绘制
        for (CustomPolygonShape shape : shapes) {
            shape.draw(g2);
        }
    }

    @Override
    public void mousePressed(MouseEvent e) {
        for (CustomPolygonShape shape : shapes) {
            if (shape.contains(e.getPoint())) {
                currShape = shape;
                mousePressX = e.getX();
                mousePressY = e.getY();
                break; // 找到第一个包含点击点的图形后即可退出
            }
        }
    }

    @Override
    public void mouseDragged(MouseEvent e) {
        if (currShape != null) {
            int dx = e.getX() - mousePressX;
            int dy = e.getY() - mousePressY;
            currShape.translate(dx, dy); // 移动当前图形
            mousePressX = e.getX(); // 更新鼠标位置
            mousePressY = e.getY(); // 更新鼠标位置
            repaint(); // 在当前 JPanel 上调用 repaint()
        }
    }

    @Override
    public void mouseReleased(MouseEvent e) {
        currShape = null; // 释放当前拖动的图形
    }

    // 其他 MouseListener/MouseMotionListener 方法保持为空或根据需要实现
    @Override public void mouseClicked(MouseEvent e) {}
    @Override public void mouseEntered(MouseEvent e) {}
    @Override public void mouseExited(MouseEvent e) {}
    @Override public void mouseMoved(MouseEvent e) {}
}

// Pentomino.java
import javax.swing.*;

public class Pentomino extends JFrame {
    public Pentomino(){
        initUI();
    }

    private void initUI(){
        setTitle("Пентамино");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(1500, 900);
        setResizable(false);

        // 创建并添加 PentominoDrawingPanel 到 JFrame
        PentominoDrawingPanel drawingPanel = new PentominoDrawingPanel();
        add(drawingPanel); // JFrame 的 add 方法默认添加到 BorderLayout.CENTER

        setLocationRelativeTo(null);
        setVisible(true);
    }

    public static void main(String[] args) {
        // 在事件调度线程中创建和显示GUI
        SwingUtilities.invokeLater(Pentomino::new);
    }
}

// CustomPolygonShape.java
import java.awt.*;

public class CustomPolygonShape {
    private Polygon polygon;
    private Color color;

    public CustomPolygonShape(Polygon polygon, Color color) {
        this.polygon = polygon;
        this.color = color;
    }

    // 绘制自身的方法
    public void draw(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        g2.setColor(color);
        g2.fill(polygon); // 填充多边形
        // g2.draw(polygon); // 如果需要，也可以绘制边框
    }

    // 判断是否包含某个点的方法
    public boolean contains(Point p) {
        return polygon.contains(p);
    }

    // 移动多边形的方法
    public void translate(int dx, int dy) {
        polygon.translate(dx, dy);
    }

    // 获取内部 Polygon 对象，如果需要直接操作
    public Polygon getPolygon() {
        return polygon;
    }

    // 获取颜色
    public Color getColor() {
        return color;
    }
}