Java刚入门，鼠标如何托动一个东西的移动

Question

去看 java 自带的 demo

Answer 1

java刚入门，请问到什么地方看？

Answer 2

如果是awt的话就使用java.awt.dnd 这个包，里面都是关于这个的类。

Answer 3

在paint(Graphics g)方法中调用drawImage在清华的坐标处画出图像，然后在鼠标拖动事件mouseDragged中调用repaint()重绘方法即可。

Answer 4

给一个例子你看看:
  package helloworld;import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.border.*;public class Frame1 extends JFrame
{
  private MyPanel jPanel1 = new MyPanel();
  private JButton jButton1 = new JButton();
  private int focusx,focusy,x,y;
  private static Frame1 frame1  = null ;
  private int px,py;
  public Frame1()
  {
    try
    {
      jbInit();
    }
    catch(Exception e)
    {
      e.printStackTrace();
    }
  }
  public static void main(String[] args)
  {
    frame1 = new Frame1();
    frame1.setSize(400,300);
    frame1.show();
  }
  private void jbInit() throws Exception
  {
    border1 = BorderFactory.createBevelBorder(BevelBorder.LOWERED,Color.white,Color.white,new Color(103, 101, 98),new Color(148, 145, 140));
    jButton1.setBounds(new Rectangle(88, 87, 79, 29));
    jButton1.setText("jButton1");
    jButton1.addMouseMotionListener(new java.awt.event.MouseMotionAdapter()
    {
      public void mouseDragged(MouseEvent e)
      {
        jButton1_mouseDragged(e);
      }
    });
    jButton1.addMouseListener(new java.awt.event.MouseAdapter()
    {
      public void mousePressed(MouseEvent e)
      {
        jButton1_mousePressed(e);
      }
    });
    jButton2.setBounds(new Rectangle(30, 15, 79, 29));
    jButton2.setText("jButton2");
    jButton3.setBounds(new Rectangle(104, 76, 79, 29));
    jButton3.setText("jButton3");
    jPanel1.setBorder(border1);
    this.getContentPane().add(jPanel1,  BorderLayout.CENTER);
    jPanel1.add(jButton1, null);
    jPanel1.add(jButton2, null);
    jPanel1.add(jButton3, null);
    px = jPanel1.getX() ;
    px = jPanel1.getY() ;
  }  void jButton1_mousePressed(MouseEvent e)
  {
      focusx = e.getX();
      focusy = e.getY();
  }  void jButton1_mouseDragged(MouseEvent e)
  {
     Container container = jButton1.getParent();
     int width = container.getWidth() ;
     int height = container.getHeight() ;     x = jButton1.getX() + e.getX() - focusx ;
     y = jButton1.getY() + e.getY() - focusy ;     jButton1.setLocation(x,y);     container.repaint();
     container= null;  }
  private JButton jButton2 = new JButton();
  private JButton jButton3 = new JButton();
  private Border border1;  class MyPanel extends JLayeredPane{     public MyPanel() {
         super();
     }     public void paint(Graphics g){
       Point p1 = new Point(jButton2.getX() + jButton2.getWidth()-jPanel1.getX(),jButton2.getY()+jButton2.getHeight() - jPanel1.getY());
       Point p2 = new Point(x,y);       Graphics2D g2 = (Graphics2D)g;
       g2.setStroke(new BasicStroke(1, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND));
       g2.setColor(Color.darkGray);
       g2.drawLine((int)p1.getX(),(int)p1.getY(),(int)p2.getX(),(int)p2.getY());       g2.setStroke(new BasicStroke(2, BasicStroke.CAP_BUTT, BasicStroke.JOIN_ROUND));
       g2.setColor(Color.gray);
       g2.drawLine((int)p1.getX(),(int)p1.getY(),(int)p2.getX(),(int)p2.getY());       super.paint(g);
     }
}
}