小编Cha*_*nia的帖子

我有这个问题困扰了我好几天.我正在制作一个特殊的油漆程序.我制作了一个JPanel,并添加了使用paint(..)方法绘制的自定义jComponents.问题是,每当我调整窗口大小时,所有添加的组件"消失"(或者只是不绘画),所以我最终得到一个空框架.

我也注意到使用这种方法时有一些奇怪的挥杆行为.我在描述此问题的代码中添加了注释.

package simple;

import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;

import javax.swing.*;

public class SimpleFrame extends JFrame {
    JPanel paintArea;
    SimpleCanvas c1;
    SimpleCanvas c2;
    ArrayList<SimpleCanvas> list;

    public static void main(String[] args) {
        SimpleFrame frame = new SimpleFrame();

    }

    public SimpleFrame() {
        super("Test");
        setSize(600,500);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        //The panel to which my SimpleCanvas objects are added
        paintArea = new JPanel();
        paintArea.setPreferredSize(new Dimension(600, 500)); 
        paintArea.addMouseListener(new paintAreaMouseEvents());
        getContentPane().add(paintArea, BorderLayout.CENTER);

        setVisible(true);
        paintArea.setVisible(true);

        //A list to hold all the objects together
        list = new ArrayList<SimpleCanvas>(10);

        //The same …