10例子22.txt

这是一本java基础教程 对新手上路有很大帮助

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Example10_22{
    public static void main(String args[]){
        JFrame fr=new JFrame();
        fr.add(new LP(),BorderLayout.CENTER);
        fr.setVisible(true);
        fr.setBounds(12,12,300,300);
        fr.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        fr.validate();
    }
}
class LP extends JLayeredPane implements MouseListener,MouseMotionListener{
    JButton button;
    JLabel label;
    int x,y,a,b,x0,y0;
    LP(){
        button=new JButton("用鼠标拖动我"); 
        label=new JLabel("用鼠标拖动我"); 
        button.addMouseListener(this);
        button.addMouseMotionListener(this);
        label.addMouseListener(this);
        label.addMouseMotionListener(this);
        setLayout(new FlowLayout());
        add(label ,JLayeredPane.DEFAULT_LAYER);
        add(button,JLayeredPane.DEFAULT_LAYER);
    }
    public void mousePressed(MouseEvent e){
        JComponent com=null;
        com=(JComponent)e.getSource(); 
        setLayer(com,JLayeredPane.DRAG_LAYER);
        a=com.getBounds().x;
        b=com.getBounds().y;
        x0=e.getX();     //获取鼠标在事件源中的位置坐标
        y0=e.getY();
    }
    public void mouseReleased(MouseEvent e){
        JComponent com=null;
        com=(JComponent)e.getSource(); 
        setLayer(com,JLayeredPane.DEFAULT_LAYER);
    }
    public void mouseEntered(MouseEvent e){}
    public void mouseExited(MouseEvent e){}
    public void mouseClicked(MouseEvent e){}
    public void mouseMoved(MouseEvent e){} 
    public void mouseDragged(MouseEvent e){
        JComponent com=null;
        if(e.getSource() instanceof JComponent){
           com=(JComponent)e.getSource(); 
           a=com.getBounds().x;
           b=com.getBounds().y;
           x=e.getX();     //获取鼠标在事件源中的位置坐标
           y=e.getY();
           a=a+x;
           b=b+y;
           com.setLocation(a-x0,b-y0);
        }
    }
}