添加改变绘图颜色的按钮答案

【问题标题】：Add buttons that change color of drawing添加改变绘图颜色的按钮
【发布时间】：2020-10-30 12:24:40
【问题描述】：

这幅画基本上是一个带有天空和太阳的两叶窗，就好像你在看窗外一样。我需要添加按钮日夜。通过单击每个按钮，天空的颜色变为深蓝色和浅蓝色，太阳的颜色相应地变为月亮的颜色。我已经添加了按钮并且它们出现了，但我似乎无法理解应该放置 actionListener 的方式以及如何访问我的 g2 变量以更改这些颜色。

public class DrawingOne extends JFrame{
    public DrawingOne() {
        Container container = getContentPane();
        container.setBackground(new Color(224, 196, 214));
        container.setLayout(new BorderLayout(20, 20));
        JButton j1 = new JButton("Day");
        JButton j2 = new JButton("Night");
        container.add(j1, BorderLayout.SOUTH);
        container.add(j2, BorderLayout.NORTH);
        setSize(DEFAULT_WITDH, DEFAULT_HEIGHT);
        DrawComponent c = new DrawComponent();
        add(c);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setVisible(true);
    }

    public static final int DEFAULT_WITDH = 700;
    public static final int DEFAULT_HEIGHT = 500;
}
class DrawComponent extends JComponent {

    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        //the base for window
        Rectangle2D.Double rectangle2Drect2 = new Rectangle2D.Double(37, 26, 458, 280);
        g2.setStroke(new BasicStroke(3));
        g2.setColor(Color.black);
        g2.draw(rectangle2Drect2);
        g2.setColor(Color.white);
        g2.fill(rectangle2Drect2);

        //left half-window
        rectangle2Drect2 = new Rectangle2D.Double(51, 40, 160, 250);
        g2.setStroke(new BasicStroke(3));
        g2.setColor(Color.black);
        g2.draw(rectangle2Drect2);
        g2.setColor(new Color(135, 206, 235));
        g2.fill(rectangle2Drect2);

        //right half-window
        rectangle2Drect2 = new Rectangle2D.Double(230, 40, 250, 250);
        g2.setStroke(new BasicStroke(3));
        g2.setColor(Color.black);
        g2.draw(rectangle2Drect2);
        g2.setColor(new Color(135, 206, 235));
        g2.fill(rectangle2Drect2);


        //основа ручки
        rectangle2Drect2 = new Rectangle2D.Double(215, 140, 10, 10);
        g2.setStroke(new BasicStroke(2));
        g2.setColor(Color.black);
        g2.draw(rectangle2Drect2);
        g2.setColor(Color.white);
        g2.fill(rectangle2Drect2);

        //ручка
        rectangle2Drect2 = new Rectangle2D.Double(217, 142, 4, 30);
        g2.setStroke(new BasicStroke(2));
        g2.setColor(Color.black);
        g2.draw(rectangle2Drect2);
        g2.setColor(Color.white);
        g2.fill(rectangle2Drect2);

        //the sun
        g2.setColor(Color.getHSBColor(197.4F, 42.6F, 92.2F));
        g2.fillOval(100, 60, 80, 80);

        //горшок
        int[] xpoints = {230 + 60, 300 + 60, 285 + 61, 244 + 60};
        int[] ypoints = {240, 240, 290, 290};
        int npoints = 4;
        g2.setColor(new Color(172, 86, 30));
        g2.fillPolygon(xpoints, ypoints, npoints);

        //ствол цветка
        g2.setStroke(new BasicStroke(5));
        g2.setColor(new Color(0, 128, 0));
        g2.drawLine(325, 200, 325, 238);

        //лепестки
        g2.setColor(new Color(255, 192, 203));

        g2.fillOval(317, 200, 22, 22);
        g2.fillOval(317, 175, 22, 22);
        g2.fillOval(317 - 15, 190, 22, 22);
        g2.fillOval(317 + 13, 190, 22, 22);
        //  g2.fillOval(317,190,22,22);

        //центр цветка
        g2.setColor(new Color(255, 165, 0));
        g2.fillOval(317, 190, 15, 15);
    }
    public static void main(String[] args) {
        DrawingOne frame = new DrawingOne();
    }
}

【问题讨论】：

在DrawComponen中添加一个方法changeColor()并通过c.changeColor()在动作监听器中调用它

标签： java swing graphics jframe jcomponent

【解决方案1】：

我用你的 GUI 制作了夜空。

我必须对您的代码进行大量更改才能使其正常工作。

我必须将JComponent 类设为内部类，以便它可以引用DrawingOne 类变量。
我必须在DrawingOne 类中移动main 方法，这样我才能启动应用程序。
我通过调用SwingUtilities invokeLater 方法启动了Java 应用程序。此方法确保在Event Dispatch Thread 上创建和执行 Swing 组件。
我在DrawingOne 构造函数中重新排列了您的语句顺序，因此它们更有意义。我将绘图面板设置为您喜欢的尺寸，而不是 JFrame。重要的是绘图面板的大小，而不是 JFrame 的大小。
我制作了DrawingOne 类变量的天空和太阳颜色，因此可以更改它们。我写了几个方法来改变颜色。
我编写了一个ActionListener 类，它根据您左键单击的按钮更改颜色。

这是完整的可运行代码。

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;

import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;

public class DrawingOne extends JFrame {

    private static final long serialVersionUID = 1L;

    public static final int DEFAULT_WIDTH = 700;
    public static final int DEFAULT_HEIGHT = 500;

    public Color sunColor;
    public Color skyColor;
    
    public DrawComponent c;

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

    public DrawingOne() {
        setDaySky();

        Container container = getContentPane();
        container.setBackground(new Color(224, 196, 214));
        container.setLayout(new BorderLayout(20, 20));
        container.setPreferredSize(
                new Dimension(DEFAULT_WIDTH, DEFAULT_HEIGHT));
        
        ButtonListener listener = new ButtonListener();

        JButton j1 = new JButton("Day");
        j1.addActionListener(listener);
        JButton j2 = new JButton("Night");
        j2.addActionListener(listener);
        container.add(j1, BorderLayout.SOUTH);
        container.add(j2, BorderLayout.NORTH);

        c = new DrawComponent();
        container.add(c, BorderLayout.CENTER);

        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }

    public void setNightSky() {
        this.sunColor = Color.getHSBColor(197.4F, 42.6F, 92.2F);
        this.skyColor = new Color(7, 78, 107);
    }

    public void setDaySky() {
        this.sunColor = Color.getHSBColor(197.4F, 42.6F, 92.2F);
        this.skyColor = new Color(135, 206, 235);
    }

    public class DrawComponent extends JComponent {

        private static final long serialVersionUID = 1L;

        @Override
        public void paint(Graphics g) {
            Graphics2D g2 = (Graphics2D) g;
            // the base for window
            Rectangle2D.Double rectangle2Drect2 = 
                    new Rectangle2D.Double(37, 26, 458, 280);
            g2.setStroke(new BasicStroke(3));
            g2.setColor(Color.black);
            g2.draw(rectangle2Drect2);
            g2.setColor(Color.white);
            g2.fill(rectangle2Drect2);

            // left half-window
            rectangle2Drect2 = 
                    new Rectangle2D.Double(51, 40, 160, 250);
            g2.setStroke(new BasicStroke(3));
            g2.setColor(Color.black);
            g2.draw(rectangle2Drect2);
            g2.setColor(skyColor);
            g2.fill(rectangle2Drect2);

            // right half-window
            rectangle2Drect2 = 
                    new Rectangle2D.Double(230, 40, 250, 250);
            g2.setStroke(new BasicStroke(3));
            g2.setColor(Color.black);
            g2.draw(rectangle2Drect2);
            g2.setColor(skyColor);
            g2.fill(rectangle2Drect2);

            // основа ручки
            rectangle2Drect2 = 
                    new Rectangle2D.Double(215, 140, 10, 10);
            g2.setStroke(new BasicStroke(2));
            g2.setColor(Color.black);
            g2.draw(rectangle2Drect2);
            g2.setColor(Color.white);
            g2.fill(rectangle2Drect2);

            // ручка
            rectangle2Drect2 = 
                    new Rectangle2D.Double(217, 142, 4, 30);
            g2.setStroke(new BasicStroke(2));
            g2.setColor(Color.black);
            g2.draw(rectangle2Drect2);
            g2.setColor(Color.white);
            g2.fill(rectangle2Drect2);

            // the sun
            g2.setColor(sunColor);
            g2.fillOval(100, 60, 80, 80);

            // горшок
            int[] xpoints = { 230 + 60, 300 + 60, 285 + 61, 244 + 60 };
            int[] ypoints = { 240, 240, 290, 290 };
            int npoints = 4;
            g2.setColor(new Color(172, 86, 30));
            g2.fillPolygon(xpoints, ypoints, npoints);

            // ствол цветка
            g2.setStroke(new BasicStroke(5));
            g2.setColor(new Color(0, 128, 0));
            g2.drawLine(325, 200, 325, 238);

            // лепестки
            g2.setColor(new Color(255, 192, 203));

            g2.fillOval(317, 200, 22, 22);
            g2.fillOval(317, 175, 22, 22);
            g2.fillOval(317 - 15, 190, 22, 22);
            g2.fillOval(317 + 13, 190, 22, 22);
            // g2.fillOval(317,190,22,22);

            // центр цветка
            g2.setColor(new Color(255, 165, 0));
            g2.fillOval(317, 190, 15, 15);
        }

    }

    public class ButtonListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent event) {
            JButton button = (JButton) event.getSource();
            if (button.getText().equals("Night")) {
                setNightSky();
            } else {
                setDaySky();
            }
            c.repaint();
        }

    }

}

【讨论】：

你好，你知道如何将这个 DrawingOne 从客户端发送到服务器吗？我有一个代码，但是当绘图在服务器端运行时，当我按下按钮时，根据 ActionListeners 没有任何变化
一种方法是将绘图转换为可以传输给客户的文本指令。对于天空，类似 sky = color(100, 100, 100)。
我将 actionPerformed 方法从 setNightSky() SetDaySky() 更改为 sunColor = Color.getHSBColor(197.4F, 42.6F, 92.2F);天空颜色 = 新颜色（135、206、235）；但是在服务器端一切都保持不变，按下按钮没有任何作用