title: Can't draw a oval in the jpanel when a button is clicked
body: <pre><code>import java.util.*;
  import java.awt.*;
  import java.awt.event.*;
  
  import javax.swing.*;
  
  import reactiontimer.ReactionTimer;
  
  class MyPanel1 extends JPanel
  {
  
      boolean showEllipse;
  
  
      protected void paintComponent(Graphics g)
      {
          super.paintComponent(g);
          Graphics2D g2 = (Graphics2D)g;
          g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                              RenderingHints.VALUE_ANTIALIAS_ON);
          g2.setPaint(Color.red);
          g2.drawOval(0, 0, 36, 36);
      }
  
  
  }
  
  public class DrawOval extends JFrame implements ActionListener
  {
      Boolean flag1=false;
      Boolean flag2=false;
      Boolean flag3=false;
      JButton name;
      JButton oval;
      JButton rectangle;
      JPanel centerPanel;
      MyPanel1 leftPanel;
      JPanel rightPanel;
      JLabel centerLabel;
      JPanel botPanel;
      JLabel label1;
      JLabel label2;
      JLabel label3;
  
      public static void main(String args[])
      {
          // [Add Your Name and section number Below]
          Gui rt = new Gui("Chengjie Lin, Section  012");
          rt.setVisible(true);
      }
  
      public DrawOval(String title)
      {
          setSize(600, 600);
          setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          setTitle(title);
          this.setVisible(true);
  
          Font buttonFont = new Font(Font.SANS_SERIF, Font.BOLD, 24);
          Container contentPane = this.getContentPane();
          contentPane.setLayout(new BorderLayout());
          botPanel=new JPanel();
  
          name = new JButton("Name");
          name.setFont(buttonFont);
          botPanel.add(name);
          //
          oval = new JButton("Oval");
          oval.setFont(buttonFont);
          botPanel.add(oval);
          //
          rectangle = new JButton("Rectangle");
          rectangle.setFont(buttonFont);
          botPanel.add(rectangle);
  
          contentPane.add(botPanel, BorderLayout.SOUTH);
  
          Font bigLabelFont = new Font(Font.SANS_SERIF, Font.BOLD, 48);
          label1=new JLabel("1");
          label1.setFont(bigLabelFont);
          label1.setHorizontalAlignment(SwingConstants.CENTER);
  
          label2=new JLabel("2");
          label2.setFont(bigLabelFont);
          label2.setHorizontalAlignment(SwingConstants.CENTER);
  
          label3=new JLabel("3");
          label3.setFont(bigLabelFont);
          label3.setHorizontalAlignment(SwingConstants.CENTER);
  
          centerPanel = new JPanel();
          leftPanel=new MyPanel1();
          rightPanel=new JPanel();
          leftPanel.setLayout(new BorderLayout());
          rightPanel.setLayout(new BorderLayout());
          centerPanel.setLayout(new BorderLayout());
      //  centerPanel.add(label1, BorderLayout.EAST);
          centerPanel.add(label2, BorderLayout.CENTER);
      //  centerPanel.add(label3, BorderLayout.WEST);
          contentPane.add(leftPanel, BorderLayout.EAST);
          contentPane.add(centerPanel, BorderLayout.CENTER);
          contentPane.add(rightPanel, BorderLayout.WEST);
  
  
          name.addActionListener(this);
          oval.addActionListener(this);
          rectangle.addActionListener(this);
  
      }
  
      public void actionPerformed(ActionEvent e)
      {
          Object source = e.getSource();
          String command = e.getActionCommand();
          System.out.println(command);
  
          // [Add Menu Code 3]
          if (source == name)
          {
              updateView1();
          }
          if (source == oval)
          {
           updateView2();
          }
          if(source==rectangle){
  
  
          }
  
  
      }
  
      void updateView1()
      {
          // [ADD Center Panel Code 2]
      if(flag2==false){
          label2.setText("cj");
      }else{
          label2.setText(null);   
      }
          flag2=!flag2;
      repaint();
      }
  
  
      void updateView2()
      {
          // [ADD Center Panel Code 2]
          //leftPanel.add(label1);
      if(flag1==false){
  
  
      }else{
          //leftPanel.removeAll();
  
      }
          flag1=!flag1;
      leftPanel.repaint();
      }
  
  }
  </code></pre>
  
  <p>I am new to the Java.This might be a stupid question to ask.I tried to draw an oval in the leftPanel when the oval button is clicked. But nothing happened when I clicked the Button. Can someone help me out plz?</p>