小编who*_*you的帖子

为什么在Java中当我尝试将窗口从屏幕一侧移动到中心时,那么整个JPanel不会重新绘制它自己？

示例:当我尝试将窗口从屏幕一侧(因此只有大约一半窗口可见)拖到中心时发生这种情况:

如果我添加一个组件监听器,然后放入repaint()该componentMoved方法,它将正常工作,但每次移动窗口时它将重新绘制.

相关代码:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class TEST extends JFrame
{

    public TEST()
    {
        super ("TEST!");
        setSize (500,400);
        setLocationRelativeTo(null);
        setContentPane(new MyPanel());
        addComponentListener(this);
    }

    class MyPanel extends JPanel
    {   
        public void paintComponent (Graphics g)
        {

            super.paintComponent(g);

            Graphics g2d =  (Graphics2D) g;

            int R = (int)(Math.random()*256);
            int G = (int)(Math.random()*256);
            int B= (int)(Math.random()*256);
            Color color = new Color(R, G, B);

            g2d.setColor(color);
            g2d.fillOval(0, 0, …