Windows或组件未显示在Java Swing中

Question

I am getting started with Java Swing using Eclipse on MacOS. I read some tutorials; however, I failed to reproduce the results: whenever I copy-paste a sample code, the result is different from what I am supposed to get.

For example, with this I get the empty window, but not the buttons and other stuff.

Another example is code from https://stackoverflow.com/a/14673412/4189299 : when I run it, I observe only this (instead of a button and two text fields):

Do I miss something or should I change some Eclipse settings?

Answer 1

You can copy paste the same code from below , once you pasted it inside your IDE . write one statement public static void main(Strings []abc) By yourself.

             import javax.swing.*;
             public class HelloWorld extends JFrame{
             public static void main(String ard[]) {
             SwingUtilities.invokeLater(new Runnable() {
             public void run() {
             new HelloWorld().setVisible(true);
             }
              });

               }
             public  HelloWorld()
             {

             setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
             setTitle("Hello World Button App");

               panel pan= new panel();
            add(pan.panel);
            pack();
            setVisible(true);
            }
           }

          class panel {

                     private JButton btn1 = new JButton("Klick!");
                     private JTextField txt1 = new JTextField(10);
                     private JTextField txt2 = new JTextField(10);
                      JPanel panel;
                      public panel() {
                      panel = new JPanel();
                      panel.add(btn1);
                      panel.add(txt1);
                      panel.add(txt2);
    }
  }

Answer 2

In the first example you should only get simple frame with no buttons at all. Just a frame with a title. Here is a Simple Example .

On the other case in the second example I tried and example is fine. Maybe you should check that you copied all code?