java - 让两个物体在 SwingBot 中移动

Question

我试图让它在按下命令时两个形状都移动。我的问题是:如何让蓝色多边形与黄色矩形一起移动？我似乎无法弄清楚，无论我做什么。任何帮助表示赞赏!谢谢!

编辑:删除了定时器代码(它是为了不同的东西)

import javax.swing.JFrame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import javax.swing.JComponent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.Color;
import java.awt.Polygon;
import java.util.Scanner;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.JFrame;
import javax.swing.Timer;

public class Original {

    public static void main(String[] args) {    
        // contruction of new JFrame object
        JFrame frame = new JFrame();    
        // mutators
        frame.setSize(400,400);
        frame.setTitle("SwingBot");    
        // program ends when window closes
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    
        Robot r = new Robot();
        frame.add(r);
        // voila!
        frame.setVisible(true);
        // your Scanner-based command loop goes here        
        int noend = 0;
        System.out.println("Type a Command:");
        while(noend == 0)
        {
             Scanner input = new Scanner(System.in);
             String command = input.next(); 
             if(command.equals("left"))
                 r.moveBot(-10,0);

             if(command.equals("right"))
                 r.moveBot(10,0);

             if(command.equals("down"))
                 r.moveBot(0,10);

             if(command.equals("up"))
                 r.moveBot(0,-10);
        }            
        // call methods on the Robot instance like w.moveBot(10,10) in response to
        // user input
    }    

    public static class Robot extends JComponent
    {
        private Rectangle rect = new Rectangle(20,60);
        private Polygon poly = new Polygon();

        public void paintComponent(Graphics g)
        {
            Graphics2D g2 = (Graphics2D) g;               
            // set the color
            g2.setColor(Color.ORANGE);                
            // draw the shape`
            g2.fill(rect);                
            int xPoly[] = {75, 125, 170, 170, 200, 105, 60};
            int yPoly[] = {75, 50, 88, 111, 125, 180, 150};    
            poly = new Polygon(xPoly, yPoly, xPoly.length); 
                super.paintComponent(g);
                g.setColor(Color.BLUE);
                g.drawPolygon(poly);                
        }

        public void moveBot(int x, int y)
        {
            // move the rectangle 
            rect.translate(x,y);
            poly.translate(x,y);
            // redraw the window
            repaint();
        }            
    }
}

Answer 1

建议:

• 不要在 paintComponent 方法中创建形状。
• 在创建它们时给它们提供可以改变的变量
• 在 Timer 或按键中，或者您尝试移动它们的任何地方，更改这些变量并调用 repaint()
• 对于多个对象，您可以有一个接口(interface)，例如Shape，其中每个Shape 都有一个move()可以调用的方法。
• 遍历这些对象的数据结构并调用它们的 move() 方法，然后 repaint()`
• 一个Shape可以有一个drawShape(Graphics g)方法，你可以在中循环遍历Shape的数据结构>paintComponent 方法并调用drawShape(g)

可以看到this answer举个例子。

---

更新

这是我上面提到的所有要点的示例。

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.AbstractAction;
import javax.swing.ActionMap;
import javax.swing.InputMap;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;

public class MoveShape extends JPanel {

    List<Shape> shapes;

    public MoveShape() {
        shapes = createShapeList();

        InputMap im = getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW);
        im.put(KeyStroke.getKeyStroke("RIGHT"), "moveRight");
        ActionMap am = getActionMap();
        am.put("moveRight", new AbstractAction() {
            @Override
            public void actionPerformed(ActionEvent e) {
                for (Shape sh : shapes) {
                    sh.moveRight();
                    repaint();
                }
            }
        });
    }

    private List<Shape> createShapeList() {
        List<Shape> list = new ArrayList<>();
        int xPoly[] = {75, 125, 170, 170, 200, 105, 60};
        int yPoly[] = {75, 50, 88, 111, 125, 180, 150};
        list.add(new MyPolygon(xPoly, yPoly, 6));
        list.add(new MyRectangle(75, 250, 150, 150));
        return list;
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Shape sh : shapes) {
            sh.drawShape(g);
        }
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(450, 450);
    }

    public class MyRectangle implements Shape {

        int x, y, width, height;

        public MyRectangle(int x, int y, int width, int height) {
            this.x = x;
            this.y = y;
            this.width = width;
            this.height = height;
        }

        @Override
        public void drawShape(Graphics g) {
            g.fillRect(x, y, width, height);
        }

        @Override
        public void moveRight() {
            x += INCREMENT;
        }

    }

    public class MyPolygon implements Shape {

        int[] xPoints;
        int[] yPoints;
        int numPoints;

        public MyPolygon(int[] xPoints, int[] yPoints, int numPoints) {
            this.xPoints = xPoints;
            this.yPoints = yPoints;
            this.numPoints = numPoints;
        }

        @Override
        public void drawShape(Graphics g) {
            g.fillPolygon(xPoints, yPoints, numPoints);
        }

        @Override
        public void moveRight() {
            for (int i = 0; i < xPoints.length; i++) {

                xPoints[i] += INCREMENT;

            }  
        }
    }

    public interface Shape {

        public static final int INCREMENT = 5;

        public void drawShape(Graphics g);

        public void moveRight();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new JFrame("Move Shapes");
                frame.add(new MoveShape());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}