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【第18章：图形界面】_事件处理

发布时间：2021-01-17 12:56:45编辑：雪饮阅读（）

 窗口事件监听

窗口事件监听需要实现java.awt.event.WindowListener接口
import java.awt.event.WindowListener ;
import java.awt.event.WindowEvent ;
import java.awt.Color ;
import javax.swing.JFrame ;
class MyWindowEventHandle implements WindowListener{
       public void windowActivated(WindowEvent e){
              System.out.println("windowActivated --> 窗口被选中") ;
       }
       public void windowClosed(WindowEvent e){
              System.out.println("windowClosed --> 窗口被关闭") ;
       }
       public void windowClosing(WindowEvent e){
              System.out.println("windowClosing --> 窗口关闭") ;
              System.exit(1) ;
       }
       public void windowDeactivated(WindowEvent e){
              System.out.println("windowDeactivated --> 取消窗口选中") ;
       }
       public void windowDeiconified(WindowEvent e){
              System.out.println("windowDeiconified --> 窗口从最小化恢复") ;
       }
       public void windowIconified(WindowEvent e){
              System.out.println("windowIconified --> 窗口最小化") ;
       }
       public void windowOpened(WindowEvent e){
              System.out.println("windowOpened --> 窗口被打开") ;
       }
};
public class TestJava{
       public static void main(String args[]){
              JFrame frame = new JFrame("Welcome To kasumi") ;
              //监听窗口事件
              frame.addWindowListener(new MyWindowEventHandle()) ;
              frame.setSize(300,150) ;
              frame.setLocation(300,200) ;
              frame.setVisible(true) ;
       }
}
D:\>javac TestJava.java
D:\>java TestJava
windowActivated --> 窗口被选中
windowOpened --> 窗口被打开
windowClosing --> 窗口关闭
java.awt.event.WindowEvent接口对应有一个适配器，则可以通过适配器来快速实现窗口监听
import java.awt.event.WindowAdapter ;
import java.awt.event.WindowEvent ;
import java.awt.Color ;
import javax.swing.JFrame ;
class MyWindowEventHandle extends WindowAdapter{
       public void windowClosing(WindowEvent e){
              System.out.println("windowClosing --> 窗口关闭") ;
              System.exit(1) ;
       }
};
public class TestJava{
       public static void main(String args[]){
              JFrame frame = new JFrame("Welcome To kasumi") ;
              frame.addWindowListener(new MyWindowEventHandle()) ;
              frame.setSize(300,150) ;
              frame.setLocation(300,200) ;
              frame.setVisible(true) ;
       }
}
D:\>javac TestJava.java
D:\>java TestJava
windowClosing --> 窗口关闭
内部类实现窗口监听
import java.awt.event.WindowAdapter ;
import java.awt.event.WindowEvent ;
import javax.swing.JFrame ;
public class TestJava{
       public static void main(String args[]){
              JFrame frame = new JFrame("Welcome To kasumi") ;
              //内部类实现窗口监听
              frame.addWindowListener(new WindowAdapter(){
                     public void windowClosing(WindowEvent e){
                            System.out.println("windowClosing --> 窗口关闭") ;
                            System.exit(1) ;
                     }
              }) ;
              frame.setSize(300,150) ;
              frame.setLocation(300,200) ;
              frame.setVisible(true) ;
       }
}
D:\>javac TestJava.java
D:\>java TestJava
windowClosing --> 窗口关闭
按钮的操作事件
import java.awt.event.ActionListener ;
import java.awt.event.ActionEvent ;
import java.awt.GridLayout ;
import javax.swing.JFrame ;
import javax.swing.JButton ;
import javax.swing.JTextField ;
import java.util.Date;
import java.text.SimpleDateFormat;
 
class ActionHandle{
       private JButton but = new JButton("click me");
       private JTextField text = new JTextField() ;
       public ActionHandle(){
              JFrame frame = new JFrame("Welcome To MLDN") ;
              frame.setLayout(new GridLayout(2,1)) ;
              //创建输入框
              frame.add(text) ;
              //创建按钮
              but.addActionListener(new ActionListener(){
                     public void actionPerformed(ActionEvent e){
                            //判断事件来源是否是指定按钮
                            if(e.getSource()==but){
                                   text.setText("你点击了click me"+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())) ;
                                  
                            }
                     }
              }) ;
              frame.add(but) ;
             
              frame.pack() ;
              frame.setLocation(300,200) ;
              frame.setVisible(true) ;
 
       }
};
public class TestJava{
       public static void main(String args[]){
               new ActionHandle() ;
       }
}

在上面例子中判断事件来源还可以通过instanceof关键字
import java.awt.event.ActionListener ;
import java.awt.event.ActionEvent ;
import java.awt.GridLayout ;
import javax.swing.JFrame ;
import javax.swing.JButton ;
import javax.swing.JTextField ;
import java.util.Date;
import java.text.SimpleDateFormat;
 
class ActionHandle{
       private JButton but = new JButton("click me");
       private JTextField text = new JTextField() ;
       public ActionHandle(){
              JFrame frame = new JFrame("Welcome To MLDN") ;
              frame.setLayout(new GridLayout(2,1)) ;
              //创建输入框
              frame.add(text) ;
              //创建按钮
              but.addActionListener(new ActionListener(){
                     public void actionPerformed(ActionEvent e){
                            //判断事件来源是否是指定按钮
                            if(e.getSource() instanceof JButton){
                                   text.setText("你点击了click me"+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date())) ;
                            }
                     }
              }) ;
              frame.add(but) ;
             
              frame.pack() ;
              frame.setLocation(300,200) ;
              frame.setVisible(true) ;
 
       }
};
public class TestJava{
       public static void main(String args[]){
               new ActionHandle() ;
       }
}

用ActionListener以内部类的形式实现密码输入框中密码的获取、重置
import java.awt.event.ActionListener ;
import java.awt.event.ActionEvent ;
import java.awt.GridLayout ;
import javax.swing.JFrame ;
import javax.swing.JButton ;
import javax.swing.JPasswordField ;
import javax.swing.JLabel ;
class ActionHandle{
       private JButton submit = new JButton("获取密码");
       private JButton reset = new JButton("重置");
       private JPasswordField passText = new JPasswordField() ;
       private JLabel nameLab = new JLabel() ;
       public ActionHandle(){
               JFrame frame = new JFrame("Welcome To kasumi") ;
               frame.setLayout(new GridLayout(5,1)) ;
               //输入密码提示标签
               JLabel infoLab = new JLabel("请输入密码") ;
               frame.add(infoLab);
               //密码输入框
               frame.add(passText);
               //获取密码
               submit.addActionListener(new ActionListener(){
                     public void actionPerformed(ActionEvent e){
                            if(e.getSource()==submit){
                                   nameLab.setText("获取的密码是:"+new String(passText.getPassword()));
                            }
                     }
              }) ;
              frame.add(submit);
              //重置密码
              reset.addActionListener(new ActionListener(){
                     public void actionPerformed(ActionEvent e){
                            if(e.getSource()==reset){
                                   passText.setText("") ;
                                   nameLab.setText("密码被重置");
                            }
                     }
              }) ;
              frame.add(reset);
              //信息输出区
              frame.add(nameLab);
              frame.pack() ;
              frame.setVisible(true) ;
       }
}
public class TestJava{
       public static void main(String args[]){
              new ActionHandle();
       }
}

键盘监听事件
实现java.awt.event.KeyListener接口可以对键盘事件进行监听
import java.awt.event.KeyListener ;
import java.awt.event.KeyEvent ;
import javax.swing.JFrame ;
import java.awt.event.ActionListener ;
import java.awt.event.ActionEvent ;
import java.awt.GridLayout ;
import javax.swing.JFrame ;
import javax.swing.JTextArea ;
 
class MyKeyHandle extends JFrame implements KeyListener{
       private JTextArea text = new JTextArea() ;
       public MyKeyHandle(){
              super.setTitle("Welcome To MLDN") ;
              text.setBounds(5,5,300,200) ;
              super.add(text) ;
              //键盘监听事件
              text.addKeyListener(this) ;
              super.setSize(310,210) ;
              super.setVisible(true) ;
       }
       public void keyPressed(KeyEvent e){
              text.append("键盘“" + KeyEvent.getKeyText(e.getKeyCode())+ "”键按下\n") ;
       }
 
       public void keyReleased(KeyEvent e){
              text.append("键盘“" + KeyEvent.getKeyText(e.getKeyCode())+ "”键松开\n") ;
       }
 
       public void keyTyped(KeyEvent e){
              text.append("输入的内容是：" + e.getKeyChar() + "\n") ;
       }
};
public class TestJava{
       public static void main(String args[]){
              new MyKeyHandle();
       }
}

用适配器（匿名内部类）实现键盘监听
import java.awt.event.KeyEvent ;
import javax.swing.JFrame ;
import java.awt.event.ActionListener ;
import java.awt.event.ActionEvent ;
import java.awt.GridLayout ;
import javax.swing.JFrame ;
import javax.swing.JTextArea ;
import java.awt.event.KeyAdapter ;
class MyKeyHandle extends JFrame{
       private JTextArea text = new JTextArea() ;
       public MyKeyHandle(){
              super.setTitle("Welcome To MLDN") ;
              text.setBounds(5,5,300,200) ;
              super.add(text) ;
              //键盘监听事件
              text.addKeyListener(new KeyAdapter(){
                     public void keyTyped(KeyEvent e){
                            text.append("输入的内容是：" + e.getKeyChar() + "\n") ;
                     }
              }) ;
              super.setSize(310,210) ;
              super.setVisible(true) ;
       }
};
public class TestJava{
       public static void main(String args[]){
              new MyKeyHandle();
       }
}

鼠标事件的监听
实现java.awt.event.MouseListener接口可以对鼠标事件进行监听
import java.awt.event.MouseListener ;
import java.awt.event.MouseEvent ;
import javax.swing.JFrame ;
import javax.swing.JTextArea ;
import javax.swing.JScrollPane ;
 
class MyMouseHandle extends JFrame implements MouseListener{
       private JTextArea text = new JTextArea() ;
       public MyMouseHandle(){
              super.setTitle("Welcome To MLDN") ;
              JScrollPane scr = new JScrollPane(text) ;
              scr.setBounds(5,5,300,200) ;
              super.add(scr) ;
              //鼠标事件监听
              text.addMouseListener(this) ;
              super.setSize(310,210) ;
              super.setVisible(true) ;
       }
       public void mouseClicked(MouseEvent e){
              int c = e.getButton() ;
              String mouseInfo = null ;
              if(c==MouseEvent.BUTTON1){
                     mouseInfo = "左键" ;
              }
              if(c==MouseEvent.BUTTON3){
                     mouseInfo = "右键" ;
              }
              if(c==MouseEvent.BUTTON2){
                     mouseInfo = "滚轴" ;
              }
              text.append("鼠标单击：" + mouseInfo + "\n") ;
       }
 
       public void mouseEntered(MouseEvent e){
              text.append("鼠标进入组件。\n") ;
       }
       public void mouseExited(MouseEvent e){
              text.append("鼠标离开组件。\n") ;
       }
       public void mousePressed(MouseEvent e){
              text.append("鼠标按下。\n") ;
       }
       public void mouseReleased(MouseEvent e){
              text.append("鼠标松开。\n") ;
       }
      
};
public class TestJava{
       public static void main(String args[]){
              new MyMouseHandle();
       }
}

适配器模式监听鼠标左右键及滚轮
import java.awt.event.MouseAdapter ;
import java.awt.event.MouseEvent ;
import javax.swing.JFrame ;
import javax.swing.JFrame ;
import javax.swing.JTextArea ;
import javax.swing.JScrollPane ;
 
class MyMouseHandle extends JFrame{
       private JTextArea text = new JTextArea() ;
       public MyMouseHandle(){
              super.setTitle("Welcome To kasumi") ;
              JScrollPane scr = new JScrollPane(text) ;
              scr.setBounds(5,5,300,200) ;
              super.add(scr) ;
              text.addMouseListener(new MouseAdapter(){
                     public void mouseClicked(MouseEvent e){
                            int c = e.getButton() ;
                            String mouseInfo = null ;
                            if(c==MouseEvent.BUTTON1){
                                   mouseInfo = "左键" ;
                            }
                            if(c==MouseEvent.BUTTON3){
                                   mouseInfo = "右键" ;
                            }
                            if(c==MouseEvent.BUTTON2){
                                   mouseInfo = "滚轴" ;
                            }
                            text.append("鼠标单击：" + mouseInfo + "\n") ;
                     }
              }) ;
              super.setSize(310,210) ;
              super.setVisible(true) ;
       }
};
public class TestJava{
       public static void main(String args[]){
              new MyMouseHandle() ;
       }
}


鼠标拖拽事件监听

内部类实现java.awt.event.MouseMotionListener则可以对鼠标拖拽事件进行监听

import java.awt.event.MouseMotionListener ;
import java.awt.event.MouseEvent ;
import javax.swing.JFrame ;
import javax.swing.JLabel ;
 
class MyMouseMotionHandle extends JFrame{
       private JLabel lab=new JLabel();
       public MyMouseMotionHandle(){
              super.setTitle("Welcome To kasumi") ;
              super.add(lab);
              super.addMouseMotionListener(new MouseMotionListener(){
                     public void mouseDragged(MouseEvent e){
                            String str="鼠标拖拽到：X = " + e.getX() + "，Y = " + e.getY();
                            lab.setText(str);
                     }
                     public void mouseMoved(MouseEvent e){
                            String str="鼠标移动到窗体。";
                            lab.setText(str);
                     }
              }) ;
              super.setSize(310,210) ;
              super.setVisible(true) ;
       }
};
public class TestJava{
       public static void main(String args[]){
              new MyMouseMotionHandle() ;
       }
}

同样，这家伙也支持适配器操作
import java.awt.event.MouseMotionListener ;
import java.awt.event.MouseEvent ;
import javax.swing.JFrame ;
import javax.swing.JLabel ;
import java.awt.event.MouseMotionAdapter ;
class MyMouseMotionHandle extends JFrame{
       private JLabel lab=new JLabel();
       public MyMouseMotionHandle(){
              super.setTitle("Welcome To kasumi") ;
              super.add(lab);
              super.addMouseMotionListener(new MouseMotionAdapter(){
                     public void mouseDragged(MouseEvent e){
                            String str="鼠标拖拽到：X = " + e.getX() + "，Y = " + e.getY();
                            lab.setText(str);
                     }
              }) ;
              super.setSize(310,210) ;
              super.setVisible(true) ;
       }
};
public class TestJava{
       public static void main(String args[]){
              new MyMouseMotionHandle() ;
       }
}