在Mac上没有显示GUI？

Question

I bought a Mac, II download netbeans for my java.

package gui;

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

public class Gui extends JFrame {

   public void Gui(){

      setTitle("Gui");
      setSize(640,320);
      setVisible(true);
}

public static void main(String[] args) {
    new Gui();
 }

}

It is very easy code and I didn't find any problem with it, but somehow the GUI is not showing up.

is GUI no suppose to show up on a Mac?

Somehow, the program didn't go through the Gui method, I tried

System.out.println("Hello");

didn't show up.

Answer 1

You think you're using a constructor but you are not! The constructor is what makes the app become a JFrame. This line:

   public void Gui() {

should be:

   public Gui() {

Also, nice to add a setMinimumSize(new Dimension(640,320));

Answer 2

I think the problem is you have a empty container, but I make an example for you:

import javax.swing.*;

public class Main {

    private static JPanel panel1;
    private static JButton button;

    public static void main(String[] args) {
        JFrame frame = new JFrame( "Main");
        panel1 = new JPanel();
        button = new JButton("Button");
        panel1.add(button);
        frame.setContentPane(panel1);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setTitle("Gui");
        frame.setSize(640,320);
        frame.setVisible(true);
    }
}