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");
        }
    }
}