在 java AWT 中更改已绘制图形 object 的颜色不起作用

Question

在 window 中绘制 object 后，我试图改变颜色，这就是我想出的，我是初学者，所以这很混乱。

import java.awt.*;
import java.awt.event.*;
import java.awt.event.WindowEvent;
import java.util.Arrays;
import java.util.List;
public class TestGraphic extends Figure {

TestGraphic(){
    setSize(600,600);
    closeFrame();
}

public static void main(String[] args) {
    TestGraphic test = new TestGraphic();
    test.setVisible(true);

}
public void paint(Graphics gui) {
    drawComponent(gui);
    
}
public void drawComponent(Graphics gui) {
     gui.drawOval(108,110,200,200);
     gui.drawOval(160,150,20,20);
     gui.drawOval(240,150,20,20);
     gui.drawRect(160,220,100,40);
     Button btn = new Button("Change color");
     btn.setBounds(30,100,80,30);
     add(btn);
     changeColor(gui,btn);
    
     
}
@Override
void draw(Graphics gui) {
    // TODO Auto-generated method stub
    
}
@Override
public boolean contains(int x, int y) {
      
      return false;
}
 private void closeFrame(){
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      }); 
 }
 

 void changeColor(Graphics gui,Button btn) {
     List<Color> colorList;
     colorList = Arrays.asList(Color.black, Color.blue , Color.cyan, Color.red, Color.green, Color.magenta, Color.orange, Color.yellow);
      
      btn.addActionListener(new ActionListener() { 
             public void actionPerformed (ActionEvent e) {  
                 for(int i = 0;i < colorList.size(); i++) {
                    gui.setColor(colorList.get(i));
                }
                  }    
              }); 
     
    
}

}

class图是一个抽象的 class 继承自java.awt.Frame任何有关如何使此代码更清晰的评论将不胜感激，谢谢。

Answer 1

在开始像自定义绘画这样复杂的事情之前，请确保您对语言和 API 的基础知识有深刻的理解

有关更多详细信息，请参阅使用 Swing 创建 GUI 、在 AWT 和 Swing中执行自定义绘画和绘画。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame();
                frame.add(new TestPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestPane extends JPanel {

        private Color desiredColor = Color.BLACK;
        private List<Color> avaliableColors = new ArrayList<>(16);

        public TestPane() {
            setLayout(new BorderLayout());
            avaliableColors.add(Color.BLACK);
            avaliableColors.add(Color.BLUE);
            avaliableColors.add(Color.CYAN);
            avaliableColors.add(Color.DARK_GRAY);
            avaliableColors.add(Color.GRAY);
            avaliableColors.add(Color.GREEN);
            avaliableColors.add(Color.LIGHT_GRAY);
            avaliableColors.add(Color.MAGENTA);
            avaliableColors.add(Color.ORANGE);
            avaliableColors.add(Color.PINK);
            avaliableColors.add(Color.RED);
            avaliableColors.add(Color.WHITE);
            avaliableColors.add(Color.YELLOW);

            JButton btn = new JButton("Change color");
            btn.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    // Randomise the colors
                    Collections.shuffle(avaliableColors);
                    desiredColor = avaliableColors.get(0);
                    repaint();
                }
            });
            add(btn, BorderLayout.SOUTH);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 400);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            g2d.setColor(desiredColor);
            g2d.drawOval(108, 110, 200, 200);
            g2d.drawOval(160, 150, 20, 20);
            g2d.drawOval(240, 150, 20, 20);
            g2d.drawRect(160, 220, 100, 40);
            g2d.dispose();
        }

    }
}

由于您刚刚开始，我可能建议您开始使用JavaFX

AWT

！！ 警告 ！！

没有人再使用 AWT，而且您在这里也不太可能获得太多支持。 这是从上一个示例转换而来的“基本”概念，请注意，默认情况下 AWT 不是双缓冲的

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.swing.JButton;

public class Test {

    public static void main(String[] args) {
        new Test();
    }

    public Test() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                Frame frame = new Frame();
                frame.add(new TestCanvas());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class TestCanvas extends Container {

        private Color desiredColor = Color.BLACK;
        private List<Color> avaliableColors = new ArrayList<>(16);

        public TestCanvas() {
            setLayout(new BorderLayout());
            avaliableColors.add(Color.BLACK);
            avaliableColors.add(Color.BLUE);
            avaliableColors.add(Color.CYAN);
            avaliableColors.add(Color.DARK_GRAY);
            avaliableColors.add(Color.GRAY);
            avaliableColors.add(Color.GREEN);
            avaliableColors.add(Color.LIGHT_GRAY);
            avaliableColors.add(Color.MAGENTA);
            avaliableColors.add(Color.ORANGE);
            avaliableColors.add(Color.PINK);
            avaliableColors.add(Color.RED);
            avaliableColors.add(Color.WHITE);
            avaliableColors.add(Color.YELLOW);

            JButton btn = new JButton("Change color");
            btn.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    // Randomise the colors
                    Collections.shuffle(avaliableColors);
                    desiredColor = avaliableColors.get(0);
                    repaint();
                }
            });
            add(btn, BorderLayout.SOUTH);
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(400, 400);
        }

        @Override
        public void paint(Graphics g) {
            super.paint(g);
            Graphics2D g2d = (Graphics2D) g.create();
            g2d.setColor(desiredColor);
            g2d.drawOval(108, 110, 200, 200);
            g2d.drawOval(160, 150, 20, 20);
            g2d.drawOval(240, 150, 20, 20);
            g2d.drawRect(160, 220, 100, 40);
            g2d.dispose();
        }

    }
}