小编use*_*070的帖子

我一直试图弄清楚我的代码出了什么问题.我们的想法是创建一个小的Paint程序,并有红色,绿色,蓝色和清晰的按钮.我有一些我能想到的工作,但无法弄清楚代码有什么问题.该程序打开,并立即关闭.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Paint{

    public static void main(String[] args){
            gui g = new gui();
            g.setVisible(true);

    }

}

 public class gui extends JComponent implements ActionListener{
    JButton red, green, blue, clear;
    Image image;
    Graphics2D draw;
    int x, y, prevX, prevY;

    gui(){
            JFrame frame = new JFrame("Paint");
            Container content = frame.getContentPane();
            content.setLayout(new BorderLayout());
            setDoubleBuffered(false);

            JPanel panel = new JPanel();
            content.add(panel, BorderLayout.SOUTH);
            panel.setPreferredSize(new Dimension(32, 68));
            panel.setMinimumSize(new Dimension(32, 68));
            panel.setMaximumSize(new Dimension(32, 68));


            red = new JButton("Red");
            green = new …