控件显示问题

Question

我在一个窗体中加入了两个JPanel面板,第一个里面有一个按钮,第二个为空. 当点击按钮后在按钮的actionPerformed函数中为第二个面板添加了两个标签,它们是重叠的,然后再进行碰撞检测让它们自动分开.现在我遇到的问题是运行时当点过按钮后标签并不立即显示,而只显示分开后的结果,请高手指教缘由!

Answer 1

JPanel 好象是flowLayout 布局的，把setLayout(null)，试试

Answer 2

设置了，不行的。我把代码帖上来大家帮我看看~~
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.BorderFactory;
import javax.swing.border.*;public class test
{
    public static void main(String[] args)
    {
     JFrame.setDefaultLookAndFeelDecorated(true);
frame f = new frame();
    }
}class frame extends JFrame
{
JButton b1,b2,b4,b5,b6;
JLabel lb,lbs;
JPanel m,p;
ImageIcon icon;
Container c;
public frame(){

super("test");
setBounds(100,100,500,500);
c=getContentPane();

Border border=BorderFactory.createBevelBorder(BevelBorder.RAISED,new Color(122,138,153),Color.DARK_GRAY);
m=new JPanel();
m.setPreferredSize(new Dimension(500,30));
m.setBorder(border);
m.setLayout(null);
m.setBackground(new Color(100,115,130));
m.setOpaque(true);
b4=new JButton("go");
b4.setBounds(253,3,80,25);
hds hd =new hds();
b4.addActionListener(hd);
m.add(b4);
p=new JPanel();
p.setLayout(null);
p.setBackground(Color.white);
c.add(m,BorderLayout.NORTH);
c.add(p,BorderLayout.CENTER);
show();
}

public static final boolean isIn(int ax, int ay, int aw,int ah, int bx, int by, int bw, int bh) {
if (by + bh < ay ||
by > ay + ah ||
bx + bw < ax ||
bx > ax + aw)
return false;
else
return true;
}
    
   private class hds implements ActionListener
{
public void actionPerformed(ActionEvent ee)
{
if(ee.getSource()==b4){
lb=new JLabel("hello");
lb.setSize(50,30);
lb.setLocation(50,50);
lb.setBorder(BorderFactory.createLineBorder(Color.black));
lb.setBackground(Color.gray);
lb.setOpaque(true);
lbs=new JLabel("sdfsfsf");
lbs.setSize(70,30);
lbs.setLocation(70,70);
lbs.setBorder(BorderFactory.createLineBorder(Color.black));
lbs.setBackground(Color.blue);
lbs.setOpaque(true);
p.add(lb);
p.add(lbs);
p.repaint();

try{
Thread.currentThread().sleep(50);
}catch(InterruptedException e){
}
while(isIn(lb.getX(),lb.getY(),lb.getWidth(),lb.getHeight(),lbs.getX(),lbs.getY(),lbs.getWidth(),lbs.getHeight()))
{

lb.setLocation(lb.getX()-1,lb.getY());
try{
Thread.currentThread().sleep(50);
}catch(InterruptedException e){
}
p.repaint();
}
}
}
    }
}为什么点击后不显示初始的重叠状态和检测过程中自动分开的过程？

Answer 3

你将 p.repaint(); 换成 p.updateUI();试试看！

Answer 4

好了,我用update(getGraphics());重绘了各个窗体后问题得到了解决.谢谢两位的帮助!

Answer 5

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.BevelBorder;
import javax.swing.border.Border;public class test
{
    public static void main(String[] args)
    {
        JFrame.setDefaultLookAndFeelDecorated(true);
        frame f = new frame();
    }
}class frame extends JFrame
{
    JButton   b1, b2, b4, b5, b6;
    JLabel    lb, lbs;
    JPanel    m, p;
    ImageIcon icon;
    Container c;    public frame()
    {        super("test");
        setBounds(100, 100, 500, 500);
        c = getContentPane();        Border border = BorderFactory.createBevelBorder(BevelBorder.RAISED,
                new Color(122, 138, 153), Color.DARK_GRAY);
        m = new JPanel();
        m.setPreferredSize(new Dimension(500, 30));
        m.setBorder(border);
        m.setLayout(null);
        m.setBackground(new Color(100, 115, 130));
        m.setOpaque(true);
        b4 = new JButton("go");
        b4.setBounds(253, 3, 80, 25);
        hds hd = new hds();
        b4.addActionListener(hd);
        m.add(b4);
        p = new JPanel();
        p.setLayout(null);
        p.setBackground(Color.white);
        c.add(m, BorderLayout.NORTH);
        c.add(p, BorderLayout.CENTER);
        show();
    }    public static final boolean isIn(int ax, int ay, int aw, int ah, int bx,
            int by, int bw, int bh)
    {
        if (by + bh < ay || by > ay + ah || bx + bw < ax || bx > ax + aw)
            return false;
        else
            return true;
    }    private class hds implements ActionListener
    {
        public void actionPerformed(ActionEvent ee)
        {
            if (ee.getSource() == b4)
            {
                lb = new JLabel("hello");
                lb.setSize(50, 30);
                lb.setLocation(50, 50);
                lb.setBorder(BorderFactory.createLineBorder(Color.black));
                lb.setBackground(Color.gray);
                lb.setOpaque(true);
                lbs = new JLabel("sdfsfsf");
                lbs.setSize(70, 30);
                lbs.setLocation(70, 70);
                lbs.setBorder(BorderFactory.createLineBorder(Color.black));
                lbs.setBackground(Color.blue);
                lbs.setOpaque(true);
                p.add(lb);
                p.add(lbs);
                p.repaint();                new Thread()
                {
                    public void run()
                    {
                        try
                        {
                            Thread.currentThread().sleep(50);
                        }
                        catch (InterruptedException e)
                        {
                        }
                        while (isIn(lb.getX(), lb.getY(), lb.getWidth(), lb
                                .getHeight(), lbs.getX(), lbs.getY(), lbs
                                .getWidth(), lbs.getHeight()))
                        {                            lb.setLocation(lb.getX() - 1, lb.getY());
                            try
                            {
                                Thread.currentThread().sleep(50);
                            }
                            catch (InterruptedException e)
                            {
                            }
                            p.repaint();
                        }
                    }
                }.start();            }
        }
    }
}

Answer 6

Thread.currentThread().sleep(50);这个得到当前线程 然后sleep
你当然看不到移开的效果 线程都被你阻塞了

Answer 7

谢谢insiku，线程我不是很懂，经你这么讲解我觉得我上边的解决方法并不算是真正的答案。多谢！