基于swing实现窗体拖拽和拉伸

本文为大家分享了swing实现窗体拖拽和拉伸的具体代码，供大家参考，具体内容如下

当用setUndecorated(true) 后 JFrame去掉标题栏后就得自己写拖拽和拉伸功能了。

下面是效果图，我的截图软件不能够截取除系统默认光标外的光标，所以各个方向光标变化在图中没有体现

代码如下：

import javax.swing.*;
import java.awt.*; 

/**
 * 窗体拖拽和拉伸
 */
public class winReSizeDemo {
 private JFrame jf;
 public winReSizeDemo(){
  jf=new JFrame();
  jf.setUndecorated(true);//去标边界和标题栏
  jf.setLocationRelativeTo(null);//窗口置中
  jf.setSize(400,400);
  jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  reSizeEvent dg = new reSizeEvent(jf);
  /**添加两个监听器**/
  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;
/**
 * 实现窗口各个方向拉伸以及拖动。
 */
public class reSizeEvent extends MouseAdapter{
 public JFrame jf;
 private Point prePos,curPos,jfPos;
 private static final double BREADTH = 15.0;//边界拉伸范围
 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位置不变，y位置变化，并且Height变化
    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位置不变，x位置变化，width变化
    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位置不变，width变化
    jf.setLocation(jfPos.x,
      jfPos.y);
    jf.setSize(jf.getWidth()+(curPos.x-prePos.x), jf.getHeight());
    break;
   case DRAG_BOTTOM://x,y位置不变，Height变化
    jf.setLocation(jfPos.x,
      jfPos.y);
    jf.setSize(jf.getWidth(), jf.getHeight()+(curPos.y-prePos.y));
    break;
   case DRAG_UPLEFT://x,y位置均变化，h,w均变化
    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位置均不变，h,w变化
    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位置不变，y,w,h变化
    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不变，xwh变化
    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;
 }
} 

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