两个问题（1）做出来的窗体组件运行后点击“添加”按钮，应该再窗体上生成一个JLabel标签，点击后能够生成但显示不出来，改变窗体大小才能显示出来。（2）生成的JLabel能够改变大小和拖动，先拖动到另一个位置，改变窗体大小后，又回到原来的位置去了。求大神知道下。
看了以前的帖子@raistlic说是重绘问题，但是按帖子方法把setVisible放在添加控件后面不起作用。使用getContentPane()invalidate.()总是提示找不到符号。
import java.awt.*;
import java.awt.event.*;
import static java.awt.BorderLayout.*;
import java.awt.event.ActionListener;
import javax.swing.*;
import javax.swing.SwingUtilities;
import javax.swing.plaf.ButtonUI;
class Win extends Frame
{
JButton jb1,jb2,jb3,jb4,jb5;//编辑、添加、修改、删除、调度
JPanel jp_button;//放置按钮的面板
JPanel jp_xianlu;//放置线路图的面板
JTextField jt; //添加 时用的text
String str1;
Win()
{
super("我的面板");
setExtendedState( Frame.MAXIMIZED_BOTH );
setLayout(new BorderLayout(30,5));
jp_button =new JPanel();
jp_button.setVisible(true);
jp_button.setOpaque(true);
jp_button.setBackground(Color.BLUE);
add(jp_button,SOUTH);
jp_xianlu =new JPanel();
jp_xianlu.setVisible(true);
jp_xianlu.setOpaque(true);
jp_xianlu.setBackground(Color.GREEN);
add(jp_xianlu,CENTER);
JTextField jt= new JTextField("我的标签");
jp_button.add(jt);
jt.setOpaque(true);
jt.setBackground(Color.RED);
jb1 = new JButton("编辑");
jb2 = new JButton("添加");
jb3 = new JButton("修改");
jb4 = new JButton("删除");
jb5 = new JButton("调度");
jp_button.add(jb1);
jp_button.add(jb2);
jp_button.add(jb3);
jp_button.add(jb4);
jp_button.add(jb5);
//Frame上添加windows监听，使之关闭按钮可用
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
//点击“添加”按钮时在jp_xianlu面板上生成JLabel
jb2.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e) {
str1 = jt.getText();
setLab(str1,100,100);
}
});
}
public void setLab(String str,int a,int b){
try
{
// BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
if(str==null)
{
System.out.println("输入不能不能为空");
}
else
{
JLabel lab= new JLabel(str); //输入标签显示内容
lab.setOpaque(true); //label 是透明的
lab.setBackground(Color.RED); //设置背景色
lab.setBounds(a,b,80,80);
//给生成的JLabel添加监听，使之可以自由改变大小并可以拖动
DnDAdapter dda =new DnDAdapter();
lab.addMouseMotionListener(dda);
jp_xianlu.add(lab);
}
}
catch(Exception e){
System.out.println(e.getMessage());
}
}
public static void main(String args[])
{
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
Win win=new Win();
//win.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
win.setLocationRelativeTo(null);
win.setVisible(true);
}
});
}
}
//自定义的可以自由实现组件拖动的监听器(摘自网络，还未完全理解)
class DnDAdapter extends MouseAdapter
{
//每个组件的信息，在进入组件时获得。
private JComponent jcom;
private Point jcomOriginPoint;//组件在容器内的坐标
private int jcomWidth,jcomHeight;
//与定位、缩放相关信息
private int a=10;//鼠标检测边沿大小
private Point pointMoved;//移动时，容器内坐标
private CurType curCuror;//
private enum CurType {LeftTop,LeftBottom,RightTop,RightBottom,Top,Bottom,Left,Right,Center}
//光标区域判断
private CurType getCurType(MouseEvent e)
{
Point p=e.getPoint();//getPoint返回组件内的坐标
//左上角 0<x<a,0<y<a
if((p.x>=0 && p.x<=a)&&(p.y>=0&&p.y<=a))
return CurType.LeftTop;
//右下角 w-a<x<w h-a<y<h
else if((p.x>=jcomWidth-a&&p.x<=jcomWidth)&&(p.y>=jcomHeight-a&&p.y<=jcomHeight))
return CurType.RightBottom;
//右上角w-a<x<w,0<y<a
else if((p.x>=jcomWidth-a&&p.x<=jcomWidth)&&(p.y>=0&&p.y<=a))
return CurType.RightTop;
//左下角0<x<a,h-a<y<h
else if((p.x>=0&&p.x<=a)&&(p.y>=jcomHeight-a&&p.y<=jcomHeight))
return CurType.LeftBottom;
//垂直：w-a<x<w && a<y<h-a 右边
else if( p.x>=jcomWidth-a && p.x<=jcomWidth && p.y>=a && p.y<=jcomHeight-a)
return CurType.Right;
//垂直：0<x<a,a<y<h-a 左边
else if(p.x>=0 && p.x<=a && p.y>=a && p.y<=jcomHeight-a)
return CurType.Left;
//水平 a<x<w-a && 0<y<a 上边
else if((p.x>=a&&p.x<=jcomWidth-a) &&p.y>=0&&p.y<=a)
return CurType.Top;
//水平 a<x<w-a &&h-a<y<h 下边
else if((p.x>=a&&p.x<=jcomWidth-a) &&p.y>=jcomHeight-a&&p.y<=jcomHeight)
return CurType.Bottom;
//中间
else
//jcom.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));//没有这句鼠标会一直保持形状
return CurType.Center;
}
private void setCurType(MouseEvent e)
{
switch(getCurType(e))
{
case LeftTop:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.NW_RESIZE_CURSOR));
curCuror=CurType.LeftTop;
break;
case LeftBottom:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.SW_RESIZE_CURSOR));
curCuror=CurType.LeftBottom;
break;
case RightTop:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.NE_RESIZE_CURSOR));
curCuror=CurType.RightTop;
break;
case RightBottom:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR));
curCuror=CurType.RightBottom;
break;
case Top:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR));
curCuror=CurType.Top;
break;
case Bottom:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR));
curCuror=CurType.Bottom;
break;
case Left:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR));
curCuror=CurType.Left;
break;
case Right:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR));
curCuror=CurType.Right;
break;
default:
jcom.setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
curCuror=CurType.Center;
break;
}
}
private void setPosition(MouseEvent e)
{
Point pointNow=e.getLocationOnScreen();
int incX=pointNow.x-pointMoved.x;//增量是相对于最后一次移动的点。
int incY=pointNow.y-pointMoved.y;
///
//System.out.print("PointNow:("+pointNow.x+","+pointNow.y+")\t");
//System.out.println("PointMoved:("+pointMoved.x+","+pointMoved.y+")\t");
Rectangle rect=new Rectangle();
switch(curCuror)
{
case LeftTop:
rect.x=jcomOriginPoint.x+incX;
rect.y=jcomOriginPoint.y+incY;
rect.width=jcomWidth-incX;
rect.height=jcomHeight-incY;
break;
case LeftBottom:
rect.x=jcomOriginPoint.x+incX;
rect.y=jcomOriginPoint.y;
rect.width=jcomWidth-incX;
rect.height=jcomHeight+incY;
break;
case RightTop:
rect.x=jcomOriginPoint.x;
rect.y=jcomOriginPoint.y+incY;
rect.width=jcomWidth+incX;
rect.height=jcomHeight-incY;
break;
case RightBottom:
rect.x=jcomOriginPoint.x;
rect.y=jcomOriginPoint.y;
rect.width=jcomWidth+incX;
rect.height=jcomHeight+incY;
break;
////////////////////////////////////////////
case Top:
rect.x=jcomOriginPoint.x;
rect.y=jcomOriginPoint.y+incY;
rect.width=jcomWidth;
rect.height=jcomHeight-incY;
break;
case Bottom:
rect.x=jcomOriginPoint.x;
rect.y=jcomOriginPoint.y;
rect.width=jcomWidth;
rect.height=jcomHeight+incY;
break;
case Left:
rect.x=jcomOriginPoint.x+incX;
rect.y=jcomOriginPoint.y;
rect.width=jcomWidth-incX;
rect.height=jcomHeight;
break;
case Right://右缩放
rect.x=jcomOriginPoint.x;
rect.y=jcomOriginPoint.y;
rect.width=jcomWidth+incX;
rect.height=jcom.getHeight();
break;
///////////////////////////////////////////////
case Center://移动
rect.x=jcomOriginPoint.x+incX;
rect.y=jcomOriginPoint.y+incY;
rect.width=jcom.getWidth();//防止出现恢复原大小问题。
rect.height=jcom.getHeight();
break;
default:
break;
}
jcom.setBounds(rect);
}
@Override
public void mouseMoved(MouseEvent e)
{
pointMoved=e.getLocationOnScreen();
jcom=(JComponent)e.getSource();//防止抖动关键在这一点
jcomOriginPoint=jcom.getLocation();//获取组件在父窗口的位置
jcomWidth=jcom.getWidth();
jcomHeight=jcom.getHeight();
///////////////////////////////////////////
setCurType(e);
//super.mouseMoved(e);
}
public void mouseDragged(MouseEvent e)
{
//相对于移动最后一点的增量
setPosition(e);
super.mouseDragged(e);
}
}
