JFrame / JLabel问题

Question

import java.awt.FlowLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class gui extends JFrame{

private static final long serialVersionUID = 1L;
private JLabel item1;

public void createGUI(){
    setTitle("Window Title");
    setLayout(new FlowLayout());

    item1 = new JLabel("This is a sentence.");
    item1.setToolTipText("This is a tip...");
    add(item1);
}

---

import javax.swing.JFrame;

public static void main(String[] args) throws Exception{

    gui guiObj = new gui();

    guiObj.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    guiObj.setSize(300,300);
    guiObj.setVisible(true);
}

---

The window's title isn't being applied and the label isn't showing up. I'm not sure why... Does anyone see something I might have overlooked?

Answer 1

You never call createGUI

gui guiObj = new gui();
guiObj.createGUI();

It would be better to use the gui constructor

Answer 2

You need to call createGUI() . That' where everything is initialized

gui guiObj = new gui();
guiObj.createGUI();

Also please follow Java naming convention. Class names should begin with capital letters ie
gui → Gui