CODEWITHSUNDEEP
javaswing
user2435080
user2435080

Reputation: 1

Can't get panels to display in JFrame

I am trying to design a calculator shell (non-functioning calculator) using Java but for some reason I cannot get the program to display my buttons. What am I doing wrong here?

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

public class Calculator extends JFrame {

    public Calculator() {
        JPanel P1 = new JPanel();
        P1.setLayout(new GridLayout(4, 4));
        //Panel Buttons
        for (int i = 1; i <= 9; i++) {
            P1.add(new JButton("" + i));
        }
        P1.add(new JButton("" + 0));
        P1.add(new JButton("."));
        P1.add(new JButton("*"));
        P1.add(new JButton("/"));
        P1.add(new JButton("+"));
        P1.add(new JButton("-"));
        P1.add(new JButton("="));
        P1.setBackground(Color.cyan);
        P1.setForeground(new Color(100, 1, 1));
        //Content panel
        JPanel P2 = new JPanel();
        P2.setLayout(new BorderLayout());
        P2.add(new JTextField("Hello world"), BorderLayout.NORTH);
        P2.add(P1, BorderLayout.CENTER);
    }


    public static void main(String[] args) {
        Calculator frame = new Calculator();
        frame.setTitle("Simple Calculator");
        frame.setSize(250, 250);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

}

OK here is what I have now...

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

public class Calculator extends JFrame
{
JPanel p1 = new JPanel();
JPanel p2 = new JPanel();
Calculator()
{
    super("Wk 3 Calculator"); setBounds(100,100,300,100);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container con = this.getContentPane();
    con.add(p1);
    con.add(p2);
    p1.setLayout(new GridLayout(4, 4));
    //Panel Buttons
for (int i =1; i <=9; i++){
    p1.add(new JButton ("" + i));
}
    p1.add(new JButton (""+0)); 
    p1.add(new JButton ("."));      
    p1.add(new JButton ("*"));
    p1.add(new JButton ("/"));
    p1.add(new JButton ("+"));
    p1.add(new JButton ("-"));
    p1.add(new JButton ("="));
    //Content panel
    p2.setLayout(new BorderLayout());
    p2.add (new JTextField("Hello world"),BorderLayout.NORTH);
    p2.add(p1, BorderLayout.CENTER); 
    //Frame specs
    Calculator frame = new Calculator();
    frame.setSize(250,250);
    frame.setTitle("Simple Calculator");
    frame.add(p1, BorderLayout.NORTH);
    frame.add(p2, BorderLayout.SOUTH);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
}
    public static void main(String[] args){new Calculator();}           
}

It is still not working :(

Upvotes: 0

Views: 2667

Answers (5)

Radu Murzea
Radu Murzea

Reputation: 10920

Well:

1). Call Swing-related code on the EDT (Event Dispatch Thread), not on the main thread. See here for more details.

2). You're not adding the P1 and P2 panels to the JFrame, so when you display the frame, it doesn't contain anything. Try calling add (P1) and add (P2).

3). You should call frame.pack() before you call frame.setVisible (true).

EDIT:

I rewrote your code (you still have a loong way into making a functional application, but it's a start):

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

public class Calculator
{
    private JFrame frame;

    public Calculator()
    {
        frame = new JFrame ("Simple Calculator");

        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.setLayout (new BorderLayout ());

        JPanel panel = new JPanel(new GridLayout(4, 4));
        JPanel p2 = new JPanel(new BorderLayout());

        for (int i = 1; i <= 9; i++)
        {
            panel.add (new JButton ("" + i));
        }

        panel.add(new JButton (""+0)); 
        panel.add(new JButton ("."));      
        panel.add(new JButton ("*"));
        panel.add(new JButton ("/"));
        panel.add(new JButton ("+"));
        panel.add(new JButton ("-"));
        panel.add(new JButton ("="));

        frame.add(panel, BorderLayout.CENTER);
        frame.add (new JTextField("Hello world"), BorderLayout.SOUTH);

        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }
    public static void main(String[] args)
    {
        SwingUtilities.invokeLater (new Runnable ()
        {
            @Override
            public void run ()
            {
                new Calculator();
            }
        });
    }
}

Upvotes: 0

Alpesh Gediya
Alpesh Gediya

Reputation: 3794

add your P2 inside JFrame

this.add(P2);
this.pack();

Upvotes: 1

qi zhang
qi zhang

Reputation: 11

this.add(P2); this.pack(); this.repain();

Upvotes: 0

Daniel Lerps
Daniel Lerps

Reputation: 5374

You are not adding the panels to the Frame. Put add(p1, BorderLayout.NORTH) and add(p2, BorderLayout.SOUTH) at the end of your constructor.

public Calculator()
{
    //rest of the construtor
    add(p1, BorderLayout.NORTH);
    add(p2, BorderLayout.SOUTH);
}

And rename them so they start with a small letter. Capital letters are for class names.

Upvotes: 1

MadProgrammer
MadProgrammer

Reputation: 347332

You're not adding anything to the frame...

Try something along the lines of

add(P1, BorderLayout.NORTH);
add(P2, BorderLayout.SOUTH);

For starters...

You might like to have a look at

Upvotes: 2

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