在Java中显示弹出消息窗口?

I read about JDialogs and JOptionPane messages but I still can't get it to work. I have a GUI class that extends JFrame. All I want to do is have a popup at the beginning of my program which informs the user about a couple of things. In my main I create the following gui:

我读过JDialogs和JOptionPane的消息，但我仍然不能让它工作。我有一个扩展JFrame的GUI类。我要做的就是在程序开始时弹出一个弹出窗口，告诉用户一些事情。在我的main中，我创建了以下gui:

GUI g = new GUI();

Right after that I was to display the window. I have tried the following in the main method:

就在那之后，我要把窗户打开。我尝试了以下主要方法:

JOptionPane.showMessageDialog(g, "work?");
JOptionPane.showMessageDialog(frame, "work?"); //(frame was used in documentation example so I tried it)

I also tried to add the pop up into the GUI class with the following

我还尝试在GUI类中添加以下内容。

JOptionPane.showMessageDialog(this, "work?"); //(I'm not exactly sure what the Frame Owner parameter is supposed to be, unless I'm confusing this with JDialog.)

In any case, how would I make this window appear? Every single one of the methods I tried compiled, and nothing happened.

无论如何，我如何使这个窗口出现?我试过的每一种方法都是经过编译的，什么都没有发生。

public class GUI extends JFrame implements ActionListener{
     private Container background;
     private static buttons etc...
     private static JLabel disp,edisp;
     private static JTextArea info;
     //setting up the GUI for my program, adding action listeners, I can post more if    necessary
}

And then I have the main where I want to call the pop up window

然后我有一个主要的地方，我想叫它弹出窗口。

public static void main(String[] args){
    GUI g = new GUI();
    JOptionPane.showMessageDialog(g,"Work?");
}

1 个解决方案

#1

Make sure that these are called near the beginning, be it in the main method or not. Also, try just setting the first parameter as null. So it reads:

请确保这些都是在开始时调用的，无论在主方法中还是在主方法中。另外，尝试将第一个参数设置为null。它写着:

JOptionPane.showMessageDialog(null,"Work?");

Also, remember to import it!

另外，记住要导入它!

#1