Java GUI: None of my panels are showing up on my Frame, but its background color and title are visible?

GRAEVEN YURI VIDEZ :

I am creating a GUI-based Calculator program. I've separated the areas into panels, which have the ff purposes:

• inputPanel: Where users will input numbers;
• numericPanel: Panel that holds the digits 0-9
• operatorPanel: Panel that holds operator symbols(+, -, *, /)
• formatPanel: Panel that will hold CLEAR, ENTER, and EXIT buttons

I added all these panels to the frame before making it visible, but when I press play, nothing shows up except for the background color. Should I be formatting them a different way?

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.concurrent.Flow;

/**
 * @author Graeven Yuri Videz
 * This is a program that simulates a simple calculator with arithmetic functions.
 */
public class calculator extends Frame implements ActionListener{

    private static JTextField firstField= new JTextField(25);
    private static JTextField num2 = new JTextField(25);

    //------------------------------------------------------------------------------------
    private static JButton b0 = new JButton("0");
    private static JButton b1 = new JButton("1");
    private static JButton b2 = new JButton("2");
    private static JButton b3 = new JButton("3");
    private static JButton b4 = new JButton("4");
    private static JButton b5 = new JButton("5");
    private static JButton b6 = new JButton("6");
    private static JButton b7 = new JButton("7");
    private static JButton b8 = new JButton("8");
    private static JButton b9 = new JButton("9");
    //-----------------------------------------------------------------------------------
    private static JButton enterButton = new JButton("Enter");
    private static JButton clearButton = new JButton("Clear");
    private static JButton exitButton = new JButton("Close");

    private static JButton addB = new JButton("+");
    private static JButton subB = new JButton("-");
    private static JButton multiB = new JButton("x");
    private static JButton divideB = new JButton("÷");


    private static JPanel inputPanel;
    private static JPanel numericPanel;
    private static JPanel operatorPanel;
    private static JPanel formatPanel;

    private static JLabel resultLabel;
    private static JLabel nameLabel = new JLabel("Created by: Yuri Videz");

    //-----------------------------------------------------------------------------------
    public void setInputPanel(JPanel panel) {
        panel.setLayout(new FlowLayout());
        JLabel firstNum = new JLabel("Enter your number:");
        panel.add(firstNum);
        panel.add(firstField);


    }

    public void setNumericPanel(JPanel panel) {
        panel.setLayout(new GridLayout(6, 3));
        panel.add(b0);
        panel.add(b1);
        panel.add(b2);
        panel.add(b3);
        panel.add(b4);
        panel.add(b5);
        panel.add(b6);
        panel.add(b7);
        panel.add(b8);
        panel.add(b9);
    }

    public void setOperatorPanel(JPanel panel) {
        JPanel operatorPanel = new JPanel();
        //operatorPanel.setLayout(new FlowLayout());
        panel.add(addB);
        panel.add(subB);
        panel.add(multiB);
        panel.add(divideB);

    }

    public void setFormatPanel(JPanel panel) {
        JPanel formatPanel = new JPanel();
        panel.setLayout(new FlowLayout());
        panel.add(enterButton);
        panel.add(clearButton);
    }


    public calculator() {
        inputPanel = new JPanel();
        setInputPanel(inputPanel);
        numericPanel = new JPanel();
        setNumericPanel(numericPanel);
        operatorPanel = new JPanel();
        setOperatorPanel(operatorPanel);
        formatPanel = new JPanel();
        setFormatPanel(formatPanel);

        setTitle("Calculator Program");
        JFrame frame = new JFrame();
        frame.getContentPane().setLayout(new GridLayout(3, 3));
        frame.add(nameLabel);
        frame.add(inputPanel);
        frame.add(numericPanel);
        frame.add(operatorPanel);
        frame.add(formatPanel);
        setBackground(Color.gray);
        setSize(350, 500);
        frame.pack();
        setVisible(true);
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

    }

    public static void main(String[] args){
        calculator calcuObject = new calculator();
    }
    @Override
    public void actionPerformed(ActionEvent ac) {


    }

}

c0der :

You have two different JFrame instances in your code.
You add all components to JFrame frame = new JFrame(); but you make the other one visible by setVisible(true);
Solution: change setVisible(true); to frame.setVisible(true);
There is no need for calculator to extend JFrame.

---

Side notes:
1. see Java naming conventions
2. Follow this link for a refactored version of your code

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