Java 移动椭圆以跟随光标

我想要一些建议：

我正在学习如何使用swing，我有一个助手建议制作一个应用程序，用户可以从一个组合框中选择JPanel的背景颜色（实现为自定义光束）。此外，我们还有其他组合框来选择形状的颜色。 用户需要移动光标并观察跟随它的五个椭圆形。然后我完成了所有的界面，我学会了如何使用计时器每100毫秒重新绘制画布

接口：

那么，我怎样才能存储椭圆形的最后五个位置呢？我的代码：

基架：

import java.awt.Color;
import java.awt.geom.Point2D;
import java.lang.reflect.Field;


public class Frame extends javax.swing.JFrame {



    public Frame() {
        initComponents();
    }


    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        chooseBackground = new javax.swing.JComboBox<>();
        chooseShape = new javax.swing.JComboBox<>();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        canvas1 = new lienzo();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        chooseBackground.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "WHITE", "BLACK", "PINK" }));
        chooseBackground.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                chooseBackgroundActionPerformed(evt);
            }
        });

        chooseShape.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "BLUE", "YELLOW", "ORANGE" }));
        chooseShape.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                chooseShapeActionPerformed(evt);
            }
        });

        jLabel1.setText("Seleccione el color:");

        jLabel2.setText("Fondo:");

        jLabel3.setText("Figura:");

        canvas1.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
            public void mouseMoved(java.awt.event.MouseEvent evt) {
                canvas1MouseMoved(evt);
            }
        });
        canvas1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseEntered(java.awt.event.MouseEvent evt) {
                canvas1MouseEntered(evt);
            }
            public void mouseExited(java.awt.event.MouseEvent evt) {
                canvas1MouseExited(evt);
            }
        });

        javax.swing.GroupLayout canvas1Layout = new javax.swing.GroupLayout(canvas1);
        canvas1.setLayout(canvas1Layout);
        canvas1Layout.setHorizontalGroup(
            canvas1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 0, Short.MAX_VALUE)
        );
        canvas1Layout.setVerticalGroup(
            canvas1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 184, Short.MAX_VALUE)
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(31, 31, 31)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel1)
                        .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                    .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                            .addComponent(canvas1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addGroup(layout.createSequentialGroup()
                                .addComponent(jLabel2)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(chooseBackground, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 59, Short.MAX_VALUE)
                                .addComponent(jLabel3)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
                                .addComponent(chooseShape, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
                        .addGap(97, 97, 97))))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(13, 13, 13)
                .addComponent(jLabel1)
                .addGap(18, 18, 18)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(chooseBackground, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(chooseShape, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel2)
                    .addComponent(jLabel3))
                .addGap(18, 18, 18)
                .addComponent(canvas1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(33, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        

    private void chooseBackgroundActionPerformed(java.awt.event.ActionEvent evt) {                                                 
        // TODO add your handling code here:
        String selection =  chooseBackground.getSelectedItem().toString();

        Color color;
        try{
        Field field = Class.forName("java.awt.Color").getField(selection);
        color = (Color)field.get(null);
        }catch(Exception e){
            color = null;
        }

        canvas1.setBackground(color);

    }                                                

    private void chooseShapeActionPerformed(java.awt.event.ActionEvent evt) {                                            
        // TODO add your handling code here:

        String selection =  chooseShape.getSelectedItem().toString();

        Color color;
        try{
        Field field = Class.forName("java.awt.Color").getField(selection);
        color = (Color)field.get(null);

        }catch(Exception e){
            color = null;
        }

        canvas1.setForeground(color);




    }                                           

    private void canvas1MouseMoved(java.awt.event.MouseEvent evt) {                                   
        // TODO add your handling code here:

        canvas1.setX(evt.getX());
        canvas1.setY(evt.getY());        
    }                                  

    private void canvas1MouseEntered(java.awt.event.MouseEvent evt) {                                     
        // TODO add your handling code here:
        canvas1.userHasMouseEntered=true;
    }                                    

    private void canvas1MouseExited(java.awt.event.MouseEvent evt) {                                    
        // TODO add your handling code here:
        canvas1.userHasMouseEntered=false;
    }                                   



    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(Frame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new Frame().setVisible(true);
            }
        });
    }







    // Variables declaration - do not modify                     
    private lienzo canvas1;
    private javax.swing.JComboBox<String> chooseBackground;
    private javax.swing.JComboBox<String> chooseShape;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    // End of variables declaration                   


}

导入java.awt.Color；
导入java.awt.geom.Point2D；
导入java.lang.reflect.Field；
公共类框架扩展了javax.swing.JFrame{
公共框架（）{
初始化组件（）；
}
@抑制警告（“未选中”）
//                           
私有组件（）{
chooseBackground=newjavax.swing.JComboBox（）；
chooseShape=newjavax.swing.JComboBox（）；
jLabel1=newjavax.swing.JLabel（）；
jLabel2=newjavax.swing.JLabel（）；
jLabel3=newjavax.swing.JLabel（）；
canvas1=新的lienzo（）；
setDefaultCloseOperation（javax.swing.WindowConstants.EXIT_ON_CLOSE）；
选择background.setModel（新的javax.swing.DefaultComboxModel（新字符串[]{“白色”、“黑色”、“粉色”}））；
选择Background.addActionListener（新java.awt.event.ActionListener（）{
public void actionPerformed（java.awt.event.ActionEvent evt）{
选择BackgroundActionPerformed（evt）；
}
});
选择shape.setModel（新的javax.swing.DefaultComboxModel（新字符串[]{“蓝色”、“黄色”、“橙色”}））；
选择shape.addActionListener（新建java.awt.event.ActionListener（））{
public void actionPerformed（java.awt.event.ActionEvent evt）{
选择已执行的形状（evt）；
}
});
jLabel1.setText（“选择颜色：”）；
jLabel2.setText（“Fondo:”）；
jLabel3.setText（“图：”）；
canvas1.addMouseMotionListener（新java.awt.event.MouseMotionAdapter（）{
public void mouseMoved（java.awt.event.MouseEvent evt）{
拉票（evt）；
}
});
canvas1.addMouseListener（新java.awt.event.MouseAdapter（）{
public void mouseenterned（java.awt.event.MouseEvent evt）{
拉票（evt）；
}
public void mouseExited（java.awt.event.MouseEvent evt）{
拉票1退出（evt）；
}
});
javax.swing.GroupLayout canvas1Layout=新建javax.swing.GroupLayout（canvas1）；
画布1.设置布局（画布1布局）；
canvas1Layout.setHorizontalGroup(
canvas1Layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGap（0，0，短.MAX_值）
);
canvas1Layout.setVerticalGroup(
canvas1Layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGap（0，184，短.MAX_值）
);
javax.swing.GroupLayout=newjavax.swing.GroupLayout（getContentPane（））；
getContentPane（）.setLayout（布局）；
layout.setHorizontalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（layout.createSequentialGroup（）
.addGap（31,31,31）
.addGroup（layout.createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（layout.createSequentialGroup（）
.addComponent（jLabel1）
.addContainerGap（javax.swing.GroupLayout.DEFAULT\u SIZE，Short.MAX\u VALUE））
.addGroup（javax.swing.GroupLayout.Alignment.TRAILING，layout.createSequentialGroup（）
.addGroup（layout.createParallelGroup（javax.swing.GroupLayout.Alignment.training）
.addComponent（canvas1，javax.swing.GroupLayout.DEFAULT\u SIZE，javax.swing.GroupLayout.DEFAULT\u SIZE，Short.MAX\u值）
.addGroup（layout.createSequentialGroup（）
.addComponent（jLabel2）
.addPreferredGap（javax.swing.LayoutStyle.ComponentPlacement.UNRELATED）
.addComponent（选择背景，javax.swing.GroupLayout.PREFERRED\u大小，javax.swing.GroupLayout.DEFAULT\u大小，javax.swing.GroupLayout.PREFERRED\u大小）
.addPreferredGap（javax.swing.LayoutStyle.ComponentPlacement.RELATED，59，Short.MAX_值）
.addComponent（jLabel3）
.addPreferredGap（javax.swing.LayoutStyle.ComponentPlacement.UNRELATED）
.addComponent（选择形状，javax.swing.GroupLayout.PREFERRED\u大小，javax.swing.GroupLayout.DEFAULT\u大小，javax.swing.GroupLayout.PREFERRED\u大小）
.addGap（97,97,97）））
);
layout.setVerticalGroup(
createParallelGroup（javax.swing.GroupLayout.Alignment.LEADING）
.addGroup（layout.createSequentialGroup（）
.addGap（13,13,13）
.addComponent（jLabel1）
.addGap（18,18,18）
.addGroup（layout.createParallelGroup（javax.swing.GroupLayout.Alignment.BASELINE）
.addComponent（选择背景，javax.swing.GroupLayout.PREFERRED\u大小，javax.swing.GroupLayout.DEFAULT\u大小，javax.swing.GroupLayout.PREFERRED\u大小）
.addComponent（选择形状、javax.swing.GroupLayout.PREFERRED\u大小、javax.swing.GroupLayout.DEFAULT\u大小、javax.swing.GroupLayout.PREFERRED\u大小）
.addComponent（jLabel2）
.addComponent（jLabel3））
.addGap（18,18,18）
.addComponent（canvas1，javax.swing.GroupLayout.PREFERRED\u SIZE，javax.swing.GroupLayout.DEFAULT\u SIZE，ja
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JPanel;
import javax.swing.Timer;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author YonePC
 */
public class lienzo extends JPanel {
    public boolean userHasMouseEntered;

    private int countSavedPos = 0;

    private int[] posX = new int[5];
    private int[] posY = new int[5];

    private int x;
    private int y;

    public void setX(int x) {
        this.x = x;
    }

    public void setY(int y) {
        this.y = y;
    }

    public lienzo() {
            Timer timer = new Timer(100, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    repaint();
                }
            });
            timer.start();

        this.setBackground(Color.white);
        this.setForeground(Color.blue);

    }


    @Override
    public  void paintComponent(Graphics g){
        super.paintComponent(g);
        if(userHasMouseEntered)
        g.fillOval(x, y, 30, 30);



        posX[countSavedPos] = x;
        posY[countSavedPos] = y;
        countSavedPos++;
        if(countSavedPos>4) countSavedPos=0;

        for (int i = 0; i < countSavedPos; i++) {
            g.fillOval(posX[countSavedPos], posY[countSavedPos], 30, 30);


        }

        //repaint();
    }


}

    private final ArrayList<Position> trail = new ArrayList<>();




public void addNewPosition(Position position){
       trail.add(0, position);       
}

public void removeLastPosition(){
    if (trail.size()> 5) trail.remove(5);
}    

    private void canvas1MouseMoved(java.awt.event.MouseEvent evt) {                                   
    // TODO add your handling code here:
    canvas1.addNewPosition(new Position(evt.getX(),evt.getY()));
    canvas1.removeLastPosition();
    repaint();

    /*
    canvas1.setX(evt.getX());
    canvas1.setY(evt.getY());*/        
}  

   @Override
public  void paintComponent(Graphics g){
    super.paintComponent(g);

    if(userHasMouseEntered){

            for (int i = 0; i < trail.size(); i++) {
                g.fillOval(trail.get(i).getX(), trail.get(i).getY(), 30, 30);
                try {
                    Thread.sleep(25);
                } catch (InterruptedException ex) {
                    Logger.getLogger(lienzo.class.getName()).log(Level.SEVERE, null, ex);
                }
            }


    }   
    repaint();
}