Mouseclicked听众不与GUI合作

Question

我创建了此程序，该程序获取鼠标坐标，现在我想添加一个鼠标，该程序在按下鼠标时会在某些坐标上创建矩形。但是它行不通。这是我的代码：

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

@SuppressWarnings("serial")
public class GameSetup extends JPanel implements MouseMotionListener {
public static JFrame njf = new JFrame("Test");
public static int x = 0, y = 0;
public static boolean c = false;
public static void main(String[] args) {
    GameSetup gs = new GameSetup();
    gs.addMouseMotionListener(gs);
    njf.add(gs);
    njf.setVisible(true);
}
public void paintComponent(Graphics g) {
    super.paintComponent(g);
    this.setBackground(Color.BLACK);
    g.setColor(Color.GREEN);
    g.drawRect(150, 75, 200, 100);
    g.setColor(Color.ORANGE);
    g.drawString("Play", 239, 123);

    if (x > 150 && y > 75 && x < 350 && y < 175){
        g.drawRect(150, 75, 200, 100);
    } 
    if(x > 150 && y > 75 && x < 350 && y < 175 && c){
        g.fillRect(10 , 10 ,100 ,100);
    }
}
public GameSetup() {
    super();
    setSize(500, 500);
    njf.setSize(500,500);
    njf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    njf.setResizable(false);
    njf.setLocationRelativeTo(null);
}
@Override
public void mouseDragged(MouseEvent arg0) {
}
@Override
public void mouseMoved(MouseEvent e) {
    x = e.getX();
    y = e.getY();
    if (x > 0 && y > 0) repaint(); else repaint();
}
public void mouseClicked(MouseEvent ea){
    c = true;
}
}

我该如何完成这项工作？谢谢

Answer 1

与充满鳗鱼的气垫船说的话，我有点重构。注意：

• 实现Mouselistener或扩展Mouseadapter，并注册听众（addMouseListener）
• 变量不需要公开或静态 - 尝试最大程度地减少范围，将更多的封装用作最佳实践
• 将repaint()添加到MouseClicked
• 将 c更改为 clicked，并使其在True和False之间切换，因此您可以看到它更改

尝试以下操作：

public class Game {
    public static void main(String[] args) {
        final JFrame frame = new JFrame("Test");
        frame.setSize(500, 500);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);
        frame.setLocationRelativeTo(null);
        frame.add(new GamePanel());
        frame.setVisible(true);
    }
    @SuppressWarnings("serial")
    private static class GamePanel extends JPanel {
        private int x = 0;
        private int y = 0;
        private boolean clicked = false;
        public GamePanel() {
            super();
            setSize(500, 500);
            setBackground(Color.BLACK);
            addMouseListener(new MouseListenerImpl());
            addMouseMotionListener(new MouseMotionListenerImpl());
        }
        @Override
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(Color.GREEN);
            g.drawRect(150, 75, 200, 100);
            g.setColor(Color.ORANGE);
            g.drawString("Play", 239, 123);
            if (x > 150 && y > 75 && x < 350 && y < 175) {
                g.drawRect(150, 75, 200, 100);
                if (clicked) {
                    g.fillRect(10, 10, 100, 100);
                }
            }
        }
        private class MouseListenerImpl extends MouseAdapter {
            @Override
            public void mouseClicked(MouseEvent e) {
                clicked = !clicked;
                repaint();
            }
        }
        private class MouseMotionListenerImpl extends MouseMotionAdapter {
            @Override
            public void mouseMoved(MouseEvent e) {
                x = e.getX();
                y = e.getY();
                repaint();
            }
        }
    }
}

Answer 2

您不能将@Override放在mouseClicked(...)上吗？那是因为您的班级无法实现适当的接口：Mouselistener。也实现此界面，也将对象添加为Mouselistener，您将可以访问Mouselistener事件。还要考虑使用您的侦听器方法进行repaint()调用，以便在必要时进行GUI重新粉刷。

我自己的偏爱不是让我的视图类也实现我的侦听器接口，因此，如果这是我的程序，我会创建一个扩展MouseAdapter的内部类，并将其用作Mouselistener和MouseMotionListener。

。

其他问题：

• 不要在绘画方法中调用setBackground。而是将其称为构造函数。
• 如果可能的话，请避免"魔术"数字。
• 考虑使用jlabel或jbutton完成这项工作，因为通常最好使用更高级别的结构来轻松调试和增强。

例如没有jlabel ...

import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.*;

@SuppressWarnings("serial")
public class GameSetup2 extends JPanel {
    private static final int PREF_W = 500;
    private static final int PREF_H = PREF_W;
    private static final Color BG = Color.BLACK;
    private static final Color PASSIVE_COLOR = Color.GREEN;
    private static final Color ACTIVE_COLOR = Color.ORANGE;
    private static final String PLAY = "Play";
    private static final int PLAY_X = 239;
    private static final int PLAY_Y = 123;
    private Rectangle rectangle = new Rectangle(150, 75, 200, 100);
    private Color rectColor = PASSIVE_COLOR;
    private Color playColor = PASSIVE_COLOR;
    public GameSetup2() {
        setBackground(BG);
        MyMouse myMouse = new MyMouse();
        addMouseListener(myMouse);
        addMouseMotionListener(myMouse);
        // TODO Auto-generated constructor stub
    }
    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D) g;
        g2.setColor(playColor);
        g2.drawString(PLAY, PLAY_X, PLAY_Y);
        g2.setColor(rectColor);
        g2.draw(rectangle);
    }
    @Override
    public Dimension getPreferredSize() {
        if (isPreferredSizeSet()) {
            return super.getPreferredSize();
        }
        return new Dimension(PREF_W, PREF_H);
    }
    private class MyMouse extends MouseAdapter {
        @Override
        public void mouseMoved(MouseEvent e) {
            if (rectangle.contains(e.getPoint())) {
                rectColor = ACTIVE_COLOR;
            } else {
                rectColor = PASSIVE_COLOR;
            }
            repaint();
        }
        @Override
        public void mousePressed(MouseEvent e) {
            if (rectangle.contains(e.getPoint())) {
                playColor = ACTIVE_COLOR;
            } 
            repaint();
        }
        public void mouseReleased(MouseEvent e) {
            playColor = PASSIVE_COLOR;
            repaint();
        };
    }
    private static void createAndShowGui() {
        GameSetup2 mainPanel = new GameSetup2();
        JFrame frame = new JFrame("GameSetup2");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> createAndShowGui());
    }
}