swing实现窗体拖拽和拉伸

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;
}
}