【Java】Java绘图技术与事件处理机制

摘要：本文主要通过实例讲解Java中绘图技术与事件处理机制

 // 此程序用来练习使用绘图技术!
  // Version:1.0
  // @Author:Yongchun_zha
  package cha08;
  import java.awt.*;
  import javax.swing.*;
  public class L8_1 extends JFrame
   {
   wdmb panl=null;
   public static void main(String[] args)
   {
    L81 l81=new L8_1();
   }
   public L8_1()
   {
    panl=new wdmb();
    this.add(panl);

    this.setTitle("Layout");//设置用户界面
    this.setSize(500,500);//设置窗口大小，数字代表像素
    this.setLocation(300,260);//设置窗体位置
    //this.setResizable(false);//设置窗体大小是否可调整
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭进程
    this.setVisible(true);//true 显示，false不显示

   }
  }

  class wdmb extends JPanel
  {
   public void paint(Graphics g)
   {
    //绘制图形
    g.setColor(Color.CYAN);//设置颜色
    g.drawOval(50, 50, 80, 80);
    g.drawLine(100,100,200,200);
    g.drawRect(100,100,200,200);
    g.draw3DRect(200,200,400,400,true);
    g.fillRect(10,10,20,20);//绘制填充图形

    //绘制图像
    Image tp=Toolkit.getDefaultToolkit().getImage(Panel.class.getResource("/notebook.jpg"));
    g.drawImage(tp,100,80,20,20,this);
    //注：绘图用到的图片要拷贝到src目录下

    //绘制文字
    g.setColor(Color.RED);
    g.setFont(new Font("华文彩云",Font.BOLD,50));
    g.drawString("Hi,大家好",200,100);
   }
   //paint方法在以下三种情况下会被系统自动调用：①启动程序 ②窗口大小发生变化 ③调用repaint函数
  }

• 事件监听

  // 此程序用来练习使用事件监听!
  // Version:1.0
  // @Author:Yongchun_zha
  package cha08;
  import java.awt.*;
  import javax.swing.*;
  import java.awt.event.*;
  public class L8_2 extends JFrame implements ActionListener//接口实现监听
  {
  wdmb2 pa=null;
  JButton bon1,bon2;
  
  public static void main(String[] args)
  {
  L82 l82=new L8_2();
  }
  
  public L8_2()
  {
  pa=new wdmb2();
  pa.setBackground(Color.CYAN);
  
  bon1=new JButton("红色");
  bon2=new JButton("蓝色");
  
  this.setLayout(new BorderLayout());
  
  this.add(bon1,BorderLayout.NORTH);
  this.add(bon2, BorderLayout.SOUTH);
  this.add(pa);
  
  bon1.addActionListener(this);//this表示监听的是本类，按需添加所需监听的类即可
  bon1.setActionCommand("111");//可以对多个类进行监听
  bon2.addActionListener(this);
  bon2.setActionCommand("222");
  
  this.setTitle("Layout");//设置用户界面
  this.setSize(500,500);//设置窗口大小，数字代表像素
  this.setLocation(300,260);//设置窗体位置
  this.setResizable(false);//设置窗体大小是否可调整
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭进程
     this.setVisible(true);//true 显示，false不显示
  }
  
  public void actionPerformed(ActionEvent e)//接口的抽象构造函数
  {
  System.out.println("按钮起作用了！");
  
  if(e.getActionCommand().equals("111"))
  {
   System.out.println("红色红色");
   pa.setBackground(Color.RED);
  }
  
  else if(e.getActionCommand().equals("222"))
  {
   System.out.println("蓝色蓝色");
   pa.setBackground(Color.BLUE);
  }
  }
  
  }
  class wdmb2 extends JPanel
  {
  public void paint(Graphics g)
  {
  super.paint(g);
  }
  }
  

• 键盘监听

  // 此程序用来练习使用事件监听!
  // Version:1.0
  // @Author:Yongchun_zha
  package cha08;
  import java.awt.*;
  import javax.swing.*;
  import java.awt.event.*;
  public class L8_3 extends JFrame
  {
  wdmb4 pan=null;
  
  public static void main(String[] args)
  {
  L83 l83=new L8_3();
  }
  
  public L8_3()
  {
  pan=new wdmb4();
  
  this.add(pan);
  this.addKeyListener(pan);
  
  this.setTitle("Layout");//设置用户界面
  this.setSize(500,500);//设置窗口大小，数字代表像素
  this.setLocation(300,260);//设置窗体位置
  this.setResizable(false);//设置窗体大小是否可调整
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭进程
     this.setVisible(true);//true 显示，false不显示
  
  }
  }
  class wdmb4 extends JPanel implements KeyListener
  {
  int x=100, y=100;
  
  public void paint(Graphics g)
  {
  super.paint(g);
     g.fillRect(x,y,30,30);
  
  }
  
  public void keyTyped(KeyEvent e)
  {
  //有字符输出的函数
  }
  
  public void keyPressed(KeyEvent e)
  {
  System.out.println("键盘被按下: "+(char)e.getKeyCode());
  if(e.getKeyCode()==KeyEvent.VK_DOWN)
  {
   System.out.println("Down");
   y+=10;
  }
  
  else if(e.getKeyCode()==KeyEvent.VK_UP)
  {
   System.out.println("Up");
   y-=10;
  }
  
  else if(e.getKeyCode()==KeyEvent.VK_RIGHT)
  {
   System.out.println("Right");
   x+=10;
  }
  
  else if(e.getKeyCode()==KeyEvent.VK_LEFT)
  {
   System.out.println("Left");
   x-=10;
  }
  
  this.repaint();
  
  }
  
  public void keyReleased(KeyEvent e)
  {
  //按键抬起
  }
  }

• 鼠标监听

  // 此程序用来练习使用鼠标监听!
  // Version:1.0
  // @Author:Yongchun_zha
  package cha08;
  import java.awt.*;
  import java.awt.event.*;
  import javax.swing.*;
  public class L8_4 extends JFrame
  {
  wdmb5 panl=null;
  
  public static void main(String[] args)
  {
  L84 l84=new L8_4();
  }
  public L8_4()
  {
  panl=new wdmb5();
  
  this.add(panl);
  
  this.addMouseListener(panl);
  this.addMouseMotionListener(panl);
  
  this.setTitle("Layout");//设置用户界面
  this.setSize(500,500);//设置窗口大小，数字代表像素
  this.setLocation(300,260);//设置窗体位置
  this.setResizable(false);//设置窗体大小是否可调整
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭进程
     this.setVisible(true);//true 显示，false不显示
  
  }
  }
  class wdmb5 extends JPanel implements MouseListener,MouseMotionListener
  {
  public void paint(Graphics g)
  {
  super.paint(g);
  }
  
  public void mouseClicked(MouseEvent e) //鼠标单击
  {
  System.out.print("鼠标点击的位置是： ");
  System.out.println("("+e.getX()+","+e.getY()+")");
  }
  
  public void mousePressed(MouseEvent e)
    {
     System.out.println("鼠标被按下");
  }
  
    public void mouseReleased(MouseEvent e)
  {
  System.out.println("鼠标被松开");
  }
  
  public void mouseEntered(MouseEvent e)
  {
  System.out.println("鼠标移动到界面中");
  }
  
  public void mouseExited(MouseEvent e)
    {
     System.out.println("鼠标离开界面");
  }
  
  public void mouseDragged(MouseEvent e)
  {
  System.out.println("鼠标当前位置是：");
  System.out.println("("+e.getX()+","+e.getY()+")");
  }
  
  public void mouseMoved(MouseEvent e)
  {
  System.out.println("鼠标当前位置是：");
  System.out.println("("+e.getX()+","+e.getY()+")");
  }
  }
  

• 窗口监听

  // 此程序用来练习使用窗口监听!
  // Version:1.0
  // @Author:Yongchun_zha
  package cha08;
  import java.awt.*;
  import java.awt.event.*;
  import javax.swing.*;
  public class L8_5 extends JFrame
  {
    Wdmb6 mb=null;
  
    public static void main(String[] args)
    {
     L85 lx=new L85();
  }
  
  L8_5()
  {
  mb=new Wdmb6();
  this.add(mb);
  this.addWindowListener(mb);
  
  
  this.setSize(400,300);
  this.setLocation(300,280);
  this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  this.setVisible(true);
  }
  }
  class Wdmb6 extends JPanel implements WindowListener
  {
  public void paint(Graphics g)
  {
  super.paint(g);
  }
  @Override
  public void windowOpened(WindowEvent e)
  {
  System.out.println("窗口打开");
  }
  public void windowClosing(WindowEvent e)
  {
   System.out.println("窗口关闭");
  }
    public void windowClosed(WindowEvent e)
    {
  }
    public void windowIconified(WindowEvent e)
    {
     System.out.println("最小化");
  }
  public void windowDeiconified(WindowEvent e)
  {
  System.out.println("从最小化变成正常");
  }
  public void windowActivated(WindowEvent e)
  {
  System.out.println("窗口被激活");
  }
  public void windowDeactivated(WindowEvent e)
  {
  
  }
  }
  

  ​