16.8

第一个程序：

import java.awt.Graphics;
import java.awt.event.*;

import javax.swing.*;

public class Test_16_8 extends JFrame{
    private int x = 0, y = 0;
    
    public Test_16_8(){
        JP jp1 = new JP();
        jp1.addMouseListener(new MouseAdapter(){
            public void mouseClicked(MouseEvent e){
                x = e.getX();
                y = e.getY();
                repaint();
            }
        });
        add(jp1);
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Test_16_8 T1 = new Test_16_8();
        T1.setTitle("Test_16.8");
        T1.setSize(200,200);
        T1.setLocationRelativeTo(null);
        T1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        T1.setVisible(true);
    }
    
    class JP extends JPanel{
        protected void paintComponent(Graphics g){
            super.paintComponent(g);
            g.drawString("("+x+","+y+")", getWidth()/2, getHeight()/2);
        }
    }
}

效果图：

第二个程序：

import java.awt.Graphics;
import java.awt.event.*;

import javax.swing.*;

public class Test_16_8 extends JFrame{
    private int x = 0, y = 0;
    
    public Test_16_8(){
        JP jp1 = new JP();
        jp1.addMouseListener(new MouseAdapter(){
            public void mousePressed(MouseEvent e){
                x = e.getX();
                y = e.getY();
                repaint();
            }
            public void mouseReleased(MouseEvent e){
                x = 0;
                y = 0;
                repaint();
            }
        });
        add(jp1);
    }
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Test_16_8 T1 = new Test_16_8();
        T1.setTitle("Test_16.8");
        T1.setSize(200,200);
        T1.setLocationRelativeTo(null);
        T1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        T1.setVisible(true);
    }
    
    class JP extends JPanel{
        protected void paintComponent(Graphics g){
            super.paintComponent(g);
            g.drawString("("+x+","+y+")", getWidth()/2, getHeight()/2);
        }
    }
}

效果图：

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