（java.lang.IllegalArgumentException）gui

Question

我在java中制作一个简单的gui程序。当我点击运行时，它给出了一个如下所示的错误：

Exception in thread "AWT-EventQueue-0" java.lang.IllegalArgumentException: adding a window to a container
at java.awt.Container.checkNotAWindow(Unknown Source)
at java.awt.Container.addImpl(Unknown Source)
at javax.swing.JLayeredPane.addImpl(Unknown Source)
at java.awt.Container.add(Unknown Source)
at javax.swing.JRootPane.setContentPane(Unknown Source)
at javax.swing.JFrame.setContentPane(Unknown Source)
at main.cool(main.java:31)
at main$1.run(main.java:43)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.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)

这是我的代码：

import javax.swing.*;

import java.awt.Container;
import java.awt.event.*;



public class main extends JFrame implements ActionListener {

protected JButton click, fun;

public main()
{
    click = new JButton("Click");
    click.setActionCommand("click");
    click.addActionListener(this);
    add(click);
    click.setSize(16, 16);
    fun = new JButton("wow");
    fun.setActionCommand("wow");
    fun.addActionListener(this);
    add(fun);

}

public static void cool()
{
    JFrame frame = new JFrame("TEST!");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    main main = new main();
    frame.setContentPane(main);
    frame.setSize(128, 128);
    frame.setVisible(true);
    frame.setResizable(true);
}


public static void main(String[] args) {
    javax.swing.SwingUtilities.invokeLater(new Runnable() { 
        public void run()
        {
            cool();
        }
    });

}





public void actionPerformed(ActionEvent e) {
    // TODO Auto-generated method stub
    if("click".equals(e.getActionCommand()))
    {
        System.out.println("oh right");
    } else if ("wow".equals(e.getActionCommand()))
    {
        System.out.println("hi");
    }
}

}

我相信bug可能在cool（）方法中;使用setContentPane行。但不确定。任何人都可以帮助我。

Answer 1

您的班级main延伸JFrame而不是JPanel，因此您在另一个frame.setContentPane()上拨打JFrame，并且没有任何意义JFrame内的JFrame。将超类更改为JPanel，错误将消失

Answer 2

是;错误是在frame.setContentPanel()课程的cool()方法的main中触发的。您的main课程应extend JPanel而不是extend JFrame。

除了：避免声明与类名匹配的局部变量;并且，避免声明与标准方法名称相同的类名...所以，将main类重命名为Main（如果必须，但尝试更具描述性......也许{{ 1}}），并使您的本地变量名称不是Application ......可能main或m。