线程"AWT-EventQueue-0"中的java异常； java.lang.IllegalArgumentException [英] java exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException

问题描述

我正在用Java swing尝试第一个代码，但遇到很多错误.我的代码是:

I was trying my first code in java swing and got many errors. my code is:

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

class Swinging extends JFrame
{
    JTextField ans;
    int count =0;
    static final long serialVersionUID = 1L; 
    Swinging()
    {
         Container cp= getContentPane();
         cp.setLayout(new FlowLayout());

         cp.add(new JLabel("value",7));

         ans=new JTextField("0",10);
         cp.add(ans);

         JButton inc= new JButton("increment");
         cp.add(inc);

         inc.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e)
            {
                ++count;
                ans.setText(count+"");
            }
         });

        setSize(200,200);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     }
 }


public class Usingswing {

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

             public void run() {
                new Swinging(); // Let the constructor do the job
             }
          });

    }

}

，错误如下:

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: horizontalAlignment
at javax.swing.JLabel.checkHorizontalKey(Unknown Source)
at javax.swing.JLabel.setHorizontalAlignment(Unknown Source)
at javax.swing.JLabel.<init>(Unknown Source)
at javax.swing.JLabel.<init>(Unknown Source)
at hopeso.Swinging.<init>(Usingswing.java:16)
at hopeso.Usingswing$1.run(Usingswing.java:45)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$400(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

我尝试使用其他人发布的问题来解决我的问题，但是没有锻炼.请帮忙.

i tried solving my problem using the questions posted by other people but it didn't workout. please help.

推荐答案

由于以下行而发生错误:

The error occurs because of the following line:

cp.add(new JLabel("value",7));

您正在使用JLabel的构造函数，该构造函数接收文本和水平对齐方式.对齐方式是int，但是必须是以下常量之一，否则它将抛出IllegalArgumentException:

You're using JLabel's constructor that receives the text and the horizontal alignment. The alignment is an int, but it has to be one of the following constants, otherwise it will throw the IllegalArgumentException:

• 左(2)
• 中心(0)
• 右(4)
• 领先(10)
• 追踪(11)

这些常量在SwingConstants中定义，因此您可以编写如下内容:

These constants are defined in SwingConstants, so you can just write something like this:

cp.add(new JLabel("value", SwingConstants.CENTER));

这篇关于线程"AWT-EventQueue-0"中的java异常； java.lang.IllegalArgumentException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！