Java中菜单的实现以及画实线与画虚线之间的自由转化

1、Java画线
  1 import java.awt.Color;
 import java.awt.Container;
 import java.awt.Graphics;
 import java.awt.Point;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;

 import javax.swing.JFrame;
 import javax.swing.JMenu;
 import javax.swing.JMenuBar;
 import javax.swing.JMenuItem;
 import javax.swing.JPanel;

 class MyPanel extends JPanel {
     public static final int MODE_LINE = 1;
     public static final int MODE_POINT = 2;
     //
     private int drawMode = MODE_POINT;

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

         // g.setColor(Color.red);
         // g.fillOval(10, 10, 100, 80);
         drawSinAdapteSize(g);

         g.dispose();
     }

     // 自适应的绘图方法
     private void drawSinAdapteSize(Graphics g) {
         g.setColor(Color.red);
         int w = getWidth();
         int h = getHeight();

         int SCALE_X = (int) (w / (2 * Math.PI));
         int SCALE_Y = h / 2 - 2;
         int OFFSET = h / 2;

         Point start = new Point(0, OFFSET);

         for (int x = 1; x <= SCALE_X * 2 * Math.PI; x++) {
             int y = OFFSET - (int) (SCALE_Y * Math.sin(x * 1.0 / SCALE_X));

             // 根据属性，决定画线还是画点
             if (drawMode == MODE_POINT) {
                 g.fillOval(x - 1, y - 1, 2, 2);
             } else if (drawMode == MODE_LINE) {
                 g.drawLine(start.x, start.y, x, y);

                 start.x = x;
                 start.y = y;
             }
         }
     }

     public void setDrawMode(int mode) {
         this.drawMode = mode;
     }

     // 绘制制定大小的曲线
     private void drawSin(Graphics g) {
         g.setColor(Color.red);
         // y = 220 - 200 * sin(x/100)
         for (int x = 0; x <= 100 * 2 * Math.PI; x++) {
             int y = 220 - (int) (200 * Math.sin(x / 100.0));

             g.fillOval(x - 1, y - 1, 2, 2);
         }
     }
 }

 public class DrawFrame extends JFrame implements ActionListener {
     // 属性
     MyPanel panel = null;

     // 方法
     public DrawFrame() {
         this.setTitle("绘图");
         setSize(650, 500);
         setDefaultCloseOperation(EXIT_ON_CLOSE);
         setLocationRelativeTo(null);

         panel = new MyPanel();
         panel.setBackground(Color.LIGHT_GRAY);

         Container cp = getContentPane();
         cp.add(panel);

         // JMenuBar
         JMenuBar menuBar = new JMenuBar();
         // JMenu
         JMenu menu = new JMenu("Draw");
         // JMenuItem
         JMenuItem item = new JMenuItem("Line");
         menu.add(item);
         item.addActionListener(this);

         item = new JMenuItem("Point");
         menu.add(item);
         item.addActionListener(this);

         menuBar.add(menu);
         this.setJMenuBar(menuBar);
     }

     public static void main(String[] args) {
         JFrame frame = new DrawFrame();
         frame.setVisible(true);
     }

     @Override
     public void actionPerformed(ActionEvent event) {
         String cmd = event.getActionCommand();
         if ("Line".equals(cmd)) {
             panel.setDrawMode(MyPanel.MODE_LINE);
         } else if ("Point".equals(cmd)) {
             panel.setDrawMode(MyPanel.MODE_POINT);
         }
         panel.repaint();
     }

 }

2、Java菜单：

 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;

 import javax.swing.JFrame;
 import javax.swing.JMenu;
 import javax.swing.JMenuBar;
 import javax.swing.JMenuItem;
 import javax.swing.JOptionPane;

 public class MenuFrame extends JFrame implements ActionListener {
     /**
      * JMuneBar(菜单栏)中包含多项Jmenu(菜单),Jmenu下有多项JMenuItem(菜单项)
      */
     public MenuFrame() {
         this.setTitle("MenuFrame");
         this.setSize(600, 400);
         setLocationRelativeTo(null);
         setDefaultCloseOperation(EXIT_ON_CLOSE);
         /**
          * 由于失误，将所有的组件都用awt下的Menu,MenuItem,MenuBar来实现了，导致菜单中的汉字为乱码
          */
         JMenuBar menuBar=new JMenuBar();
         JMenu menu=new JMenu("File");
         JMenuItem menuItem=new JMenuItem("新建");
         JMenuItem exit=new JMenuItem("退出");
         exit.addActionListener(this);

         JMenuItem about=new JMenuItem("关于...");
         about.addActionListener(this);
         menu.add(menuItem);
         menu.add(exit);
         menu.add(about);
         menuBar.add(menu);

         menuBar.add(new JMenu("Edit"));

         this.setJMenuBar(menuBar);//注意最后要将菜单栏加到MenuFrame组件中去，不然菜单不可见
     }
     public static void main(String[] args) {
         JFrame frame=new MenuFrame();
         frame.setVisible(true);
     }
     @Override
     public void actionPerformed(ActionEvent e) {
         String cmd=e.getActionCommand();
         if(cmd.equals("Exit")) {
             dispose();
         }else if(cmd.equals("About")) {
             JOptionPane.showMessageDialog(null, "菜单演示系统");
         }
     }
 }