绘图 4 圈一个按钮不同的大小和颜色

Question

我正在尝试执行此代码以输出与图片相同的结果

它应该从一个黑色圆圈开始，然后当我单击按钮时，会出现一个白色圆圈，向右移动并变大 20 像素，依此类推 在第四个圆圈之后，它应该清除窗口并从头开始，我一直只得到一个圆圈颜色或两个圆圈

这是代码

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

public class CircleList extends JFrame implements ActionListener {
    JButton addCircle;
    int nCircle = 1;
    int step = 0;
    int shift = 0;
    int d = 0;

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

    private class Circle {
        public int x1;
        public int y1;
        public int w;
        public int h;
        public Color color;
    }

    private List<Circle> whiteList = new ArrayList<>();
    private List<Circle> blackList = new ArrayList<>();


    public CircleList() {
        super("CircleList");
        setSize(500,500);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);        
        getContentPane().setBackground(Color.gray);
        addCircle = new JButton("Add Circle");
        add(addCircle,BorderLayout.SOUTH);
        addCircle.addActionListener(this);
        repaint();

        setVisible(true);
    }

    public void paint(Graphics g){
        super.paint(g);
        g.fillOval(35, 35, 35, 35);
        if (d==1) {
            for (Circle s: whiteList ) {
                paintWhiteCircle(g, s);
            }
            addWhiteCircle();
        }
        else if (d==2) {
            for (Circle s: blackList ) {
                 paintBlackCircle(g, s);

            }
            addBlackCircle();
        }
    }

    public void paintWhiteCircle(Graphics g, Circle circle) {
        g.setColor(circle.color);
        g.fillOval(circle.x1, circle.y1,  circle.w, circle.h);
    }

    public void paintBlackCircle(Graphics g, Circle circle) {
        g.setColor(circle.color);
        g.fillOval(circle.x1, circle.y1, circle.w, circle.h);
    }

    public void addBlackCircle(){

        Circle circle = new Circle();

        circle.x1 = 40 + shift;
        circle.y1 = 30 ;
        circle.w = 30 + step;
        circle.h = 30 + step;
        circle.color = new Color(0,0,0);
        this.blackList.add(circle);
    }
    public void addWhiteCircle() {

        Circle circle = new Circle();
        circle.x1 = 100 + shift;
        circle.y1 = 30 ;
        circle.w = 50 + step;
        circle.h = 50 + step;
        circle.color =  new Color(255*65536+255*256+255);       
        this.whiteList.add(circle);
    }

    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();
        d = 0;
        if (source == addCircle) {      
            for (nCircle = 2; nCircle <= 5; nCircle++) {
                if (nCircle == 2) {
                    d = 1;
                    step+=20;
                    shift += 20;
                    nCircle++;  
                }
                else if (nCircle == 3) {
                    d = 2;
                    step+=20;
                    shift += 20;
                }
                else if (nCircle == 4) {
                    d=1;
                    step+=20;
                    shift += 20;
                }
                else if (nCircle == 5)
                    repaint(); // it should clear the window and start with one circle like the beginning
                }

                repaint();
           }
      }
}

输出应该是这样的

Answer 1

我已经更正了您的示例。现在可以了。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.List;

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

public class CircleList extends JPanel implements ActionListener, Runnable {

    private static final int INTERVAL = 20;

    private static final int INITIAL_DIAMETR = 20;

    private int actualXPos;

    private final List<Circle> circleList = new ArrayList<>();

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new CircleList());
    }

    @Override
    public void run() {
        JFrame frm = new JFrame(getClass().getSimpleName());
        frm.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frm.getContentPane().add(this);
        frm.pack();
        frm.setLocationRelativeTo(null);
        frm.setVisible(true);
    }

    public CircleList() {
        setLayout(new BorderLayout());
        setPreferredSize(new Dimension(500, 500));
        setBackground(Color.gray);
        JButton addCircle = new JButton("Add Circle");
        add(addCircle, BorderLayout.SOUTH);
        addCircle.addActionListener(this);
        addCircle();
    }

    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        for (Circle c : circleList) {
            c.paint(g);
        }
    }

    private void addCircle() {

        Circle circle = new Circle();

        int num = circleList.size();
        circle.x1 = 40 + actualXPos;
        circle.y1 = 30;
        circle.w = 30 + INITIAL_DIAMETR * (num + 1);
        circle.h = 30 + INITIAL_DIAMETR * (num + 1);
        circle.color = num % 2 == 0 ? Color.BLACK : Color.WHITE;
        circleList.add(circle);
        actualXPos += circle.w + INTERVAL;
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (circleList.size() == 4) {
            circleList.clear();
            actualXPos = 0;
        }
        addCircle();
        repaint();
    }

    private static class Circle {
        private int x1;

        private int y1;

        private int w;

        private int h;

        private Color color;

        public void paint(Graphics g) {
            g.setColor(color);
            g.fillOval(x1, y1, w, h);
        }
    }
}