import javax.swing.*; import java.awt.*;  /**  * 窗體拖拽和拉伸  */ public class winReSizeDemo {  private JFrame jf;  public winReSizeDemo(){   jf=new JFrame();   jf.setUndecorated(true);//去標邊界和標題欄   jf.setLocationRelativeTo(null);//窗口置中   jf.setSize(400,400);   jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   reSizeEvent dg = new reSizeEvent(jf);   /**添加兩個監聽器**/   jf.addMouseListener(dg);   jf.addMouseMotionListener(dg);   jf.setVisible(true);  }  public static void main(String [] args){   new winReSizeDemo();  } } 

import javax.swing.*; import java.awt.*; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; /**  * 實現窗口各個方向拉伸以及拖動。  */ public class reSizeEvent extends MouseAdapter{  public JFrame jf;  private Point prePos,curPos,jfPos;  private static final double BREADTH = 15.0;//邊界拉伸范圍  private int dragType;  private static final int DRAG_MOVE = 1;  private static final int DRAG_UP = 2;  private static final int DRAG_UPLEFT = 3;  private static final int DRAG_UPRIGHT = 4;  private static final int DRAG_LEFT = 5;  private static final int DRAG_RIGHT = 6;  private static final int DRAG_BOTTOM = 7;  private static final int DRAG_BOTTOMLEFT = 8;  private static final int DRAG_BOTTOMRIGHT = 9;  public reSizeEvent(JFrame jf){   this.jf = jf;  }  @Override  public void mousePressed(MouseEvent e){   prePos = e.getLocationOnScreen();  }  @Override  public void mouseMoved(MouseEvent e){   areaCheck(e.getPoint());  }  @Override  public void mouseDragged(MouseEvent e){   curPos = e.getLocationOnScreen();   jfPos = jf.getLocation();   dragAction();   prePos = curPos;  }  private void dragAction(){   switch(dragType){    case DRAG_MOVE:     jf.setLocation(jfPos.x+curPos.x-prePos.x,       jfPos.y+curPos.y-prePos.y);     break;    case DRAG_UP://x位置不變，y位置變化，并且Height變化     jf.setLocation(jfPos.x,       jfPos.y+curPos.y-prePos.y);     jf.setSize(jf.getWidth(), jf.getHeight()-(curPos.y-prePos.y));     break;    case DRAG_LEFT://y位置不變，x位置變化，width變化     jf.setLocation(jfPos.x+curPos.x-prePos.x,       jfPos.y);     jf.setSize(jf.getWidth()-(curPos.x-prePos.x), jf.getHeight());     break;    case DRAG_RIGHT://x,y位置不變，width變化     jf.setLocation(jfPos.x,       jfPos.y);     jf.setSize(jf.getWidth()+(curPos.x-prePos.x), jf.getHeight());     break;    case DRAG_BOTTOM://x,y位置不變，Height變化     jf.setLocation(jfPos.x,       jfPos.y);     jf.setSize(jf.getWidth(), jf.getHeight()+(curPos.y-prePos.y));     break;    case DRAG_UPLEFT://x,y位置均變化，h,w均變化     jf.setLocation(jfPos.x+curPos.x-prePos.x,       jfPos.y+curPos.y-prePos.y);     jf.setSize(jf.getWidth()-(curPos.x-prePos.x), jf.getHeight()-(curPos.y-prePos.y));     break;    case DRAG_BOTTOMRIGHT://x,y位置均不變，h,w變化     jf.setLocation(jfPos.x,       jfPos.y);     jf.setSize(jf.getWidth()+(curPos.x-prePos.x), jf.getHeight()+(curPos.y-prePos.y));     break;    case DRAG_UPRIGHT://x位置不變，y,w,h變化     jf.setLocation(jfPos.x,       jfPos.y+curPos.y-prePos.y);     jf.setSize(jf.getWidth()+(curPos.x-prePos.x), jf.getHeight()-(curPos.y-prePos.y));     break;    case DRAG_BOTTOMLEFT://y不變，xwh變化     jf.setLocation(jfPos.x+curPos.x-prePos.x,       jfPos.y);     jf.setSize(jf.getWidth()-(curPos.x-prePos.x), jf.getHeight()+(curPos.y-prePos.y));     break;    default:     break;   }  }  private boolean areaCheck(Point p){   if(p.getX()<=BREADTH && p.getY()<=BREADTH){    dragType = DRAG_UPLEFT;    jf.setCursor(new Cursor(Cursor.NW_RESIZE_CURSOR));   }else if(p.getX()>BREADTH     && p.getX()<(jf.getWidth()-BREADTH)     && p.getY()<=BREADTH){    dragType = DRAG_UP;    jf.setCursor(new Cursor(Cursor.N_RESIZE_CURSOR));   }else if(p.getX()>=(jf.getWidth()-BREADTH) && p.getY()<=BREADTH){    dragType = DRAG_UPRIGHT;    jf.setCursor(new Cursor(Cursor.NE_RESIZE_CURSOR));   }else if(p.getX()<=BREADTH     && p.getY()<(jf.getHeight()-BREADTH)     && p.getY()>BREADTH){    dragType = DRAG_LEFT;    jf.setCursor(new Cursor(Cursor.W_RESIZE_CURSOR));   }else if(p.getX()>=(jf.getWidth()-BREADTH)     && p.getY()<(jf.getHeight()-BREADTH)     && p.getY()>BREADTH){    dragType = DRAG_RIGHT;    jf.setCursor(new Cursor(Cursor.E_RESIZE_CURSOR));   }else if(p.getX()<=BREADTH     && p.getY()>=(jf.getHeight()-BREADTH)){    dragType = DRAG_BOTTOMLEFT;    jf.setCursor(new Cursor(Cursor.SW_RESIZE_CURSOR));   }else if(p.getX()>BREADTH     && p.getX()<(jf.getWidth()-BREADTH)     && p.getY()>=(jf.getHeight()-BREADTH)){    dragType = DRAG_BOTTOM;    jf.setCursor(new Cursor(Cursor.S_RESIZE_CURSOR));   }else if(p.getX()>=(jf.getWidth()-BREADTH)     && p.getY()>=(jf.getHeight()-BREADTH)){    dragType = DRAG_BOTTOMRIGHT;    jf.setCursor(new Cursor(Cursor.SE_RESIZE_CURSOR));   }else{    dragType = DRAG_MOVE;    jf.setCursor(new Cursor(Cursor.MOVE_CURSOR));    return false;   }   return true;  } }