请教java程序 哪儿出错了

来源：百度知道 编辑：UC知道 时间：2024/07/04 23:20:45
import java.awt.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.event.*;

public class Painting extends JFrame implements MouseListener ,
ActionListener,MouseMotionListener
{
private int sx=0;
private int sy=0;
private int ex=0;
private int ey=0;

public static void main(String[] args)
{
Painting abc = new Painting();
abc.setVisible(true);
}

public static final int HEIGHT = 600;
public static final int WEIGHT =600;

public Painting()
{
setSize(HEIGHT,WEIGHT);
setTitle("涂鸦");
Container paintPanel= getContentPane();
paintPanel.setLayout(new BorderLayout());

JPanel barPanel = new JPanel();
paintPanel.add(barPanel,BorderLayout.NORTH);
JButton tuxing ;
tuxing = new JButton("直线");
tuxing.addMouseListener(this);
barPanel.add(tuxing);
}

//我看了你程序,完全不知所云,幸亏知道你要做什么,给你改了一下,你好好的梳理你思路.

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

public class Painting extends JFrame implements MouseListener, ActionListener,
MouseMotionListener {
private int sx = 0;

private int sy = 0;
Graphics g=null;//定义一个关于该JFrame的画笔。这样就只有一个画笔了，才能画出东西。
public static void main(String[] args) {
Painting abc = new Painting();
}

public static final int HEIGHT = 600;

public static final int WEIGHT = 600;

public Painting() {
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setSize(HEIGHT, WEIGHT);
setTitle("涂鸦");
Container paintPanel = getContentPane();
paintPanel.addMouseListener(this);
paintPanel.setLayout(new BorderLayout());

JPanel barPanel = new JPanel();
paintPanel.add(barPanel, BorderLayout.NORTH);
setV