为什么我得到{错误?

时间:2012-02-06 18:37:38

标签: java swing

我得到java:105:错误:非法字符:\ 29 }

我正在编写一个程序,用户可以点击右/左/上/下按钮并在屏幕上移动“球”。

我无法弄清楚我做错了什么。有人可以帮帮我吗?

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

public class Lab2a extends JFrame {

Lab2a(){
    setTitle("Lab 1b - Application #2");
    Lab2Panel p = new Lab2Panel();
    add(p);
}

public static void main(String[] args){

    Lab2 frame = new Lab2();
    frame.setTitle("Lab2 Application # 1");
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(600, 400);
    frame.setVisible(true);
    }

}

class Lab2Panel extends JPanel{
Lab2Button canvas = new Lab2Button();
JPanel panel = new JPanel();

Lab2Panel () {

    setLayout(new BorderLayout());

    JButton leftButton = new JButton("left");
    JButton rightButton = new JButton("right");
    JButton upButton = new JButton("up");
    JButton downButton = new JButton("down");

    panel.add(leftButton);
    panel.add(rightButton);
    panel.add(upButton);
    panel.add(downButton);

    this.add(canvas, BorderLayout.CENTER);
    this.add(panel, BorderLayout.SOUTH);

    leftButton.addActionListener(new LeftListener(canvas));
    rightButton.addActionListener(new RightListener(canvas));
    upButton.addActionListener(new UpListener(canvas));
    downButton.addActionListener(new DownListener(canvas));
}


}

class Lab2Button extends JPanel {
int radius = 5;
int x = -1;
int y = -1;

protected void paintComponent(Graphics g){
    if (x<0 || y<0) {
        x = getWidth() / 2 - radius;
        y = getHeight() / 2 - radius;
    }
    super.paintComponent(g);
    g.drawOval(x,y, 2 * radius, 2 * radius);

}

        public void moveLeft(){

            x -= 5;
            this.repaint();
        }

        public void moveRight(){

            x += 5;
            this.repaint();
        }

        public void moveUp(){
            y += 5;
            this.repaint();
        }

        public void moveDown(){
            y -= 5;
            this.repaint();
        }


}

class LeftListener implements ActionListener{
    private Lab2Button canvas;

    LeftListener(Lab2Button canvas) {
     this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
     canvas.moveLeft();
    }
}

很抱歉105就是这一行。

class RightListener implements ActionListener{
    private Lab2Button canvas;

    RightListener(Lab2Button canvas) {
        this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
      canvas.moveRight();
    }
}


class UpListener implements ActionListener{
    private Lab2Button canvas;

    UpListener(Lab2Button canvas) {
        this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
        canvas.moveUp();
    }
}



class DownListener implements ActionListener{
    private Lab2Button canvas;

    DownListener(Lab2Button canvas) {
        this.canvas = canvas;
    }

    public void actionPerformed(ActionEvent e){
     canvas.moveDown();
    }
}

4 个答案:

答案 0 :(得分:2)

所以,似乎存在一些问题,但并不完全像你所描述的那样。

  1. 第15行Lab2 frame = new Lab2();大概应为Lab2a frame = new Lab2a();,或者您错过了包含Lab2对象的声明。

  2. 问题1解决后,代码编译正常。这意味着错误发生在两个地方之一。

    1. 您可能排除的Lab2声明。

    2. 源文件的字节,在这种情况下,最好的想法是从其他源(如StackOverflow)中删除并重新粘贴代码,或者更好地重新键入代码。您可以在此过程中改进格式:)

答案 1 :(得分:2)

我尝试使用您的代码并简单地更改(第20行):

Lab2 frame = new Lab2();

Lab2a frame = new Lab2a();

它是否在我的机器上正常工作..减去上下颠倒的事实:P

编辑:NetBeans也会自动解决您的导入:

import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

根据你所拥有的,这可能在让它为我工作方面发挥了作用。

答案 2 :(得分:1)

没有行号,很难猜到,但看起来你有两个紧密的括号,你不应该:

public static void main(String[] args){

    Lab2 frame = new Lab2();
    frame.setTitle("Lab2 Application # 1");
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(600, 400);
    frame.setVisible(true);
    }  <--- EXTRA

}

更新:如果你的意图是一个类,其余的是内部类,那么上面标记为额外的括号应该移动到文件的底部。

答案 3 :(得分:1)

无法理解错误在哪里..

public static void main(String[] args){

    Lab2 frame = new Lab2();
}

你的意思是这段代码中的Lab2a?