Designing a Calculator in Java

Question

I'm new in Java and I'm finding it hard to implement a GUI here unlike in Visual Basic.

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


public class CalculatorGui extends JFrame{
    private static final int WIDTH = 250;
    private static final int HEIGHT = 250;

    private JTextField enterTextField;

    private JButton sevenB, eightB, nineB, divideB, fourB, fiveB, sixB, multiplyB, oneB, twoB, threeB, subtractB, zeroB, dotB, equalsB, addB;

    public CalculatorGui() {
        setTitle("Calculator");
        setSize(WIDTH, HEIGHT);

        setLayout(new GridLayout(4, 4));

        enterTextField = new JTextField(30);

        sevenB = new JButton("7");
        eightB = new JButton("8");
        nineB = new JButton("9");
        divideB = new JButton("/");
        fourB = new JButton("4");
        fiveB = new JButton("5");
        sixB = new JButton("6");
        multiplyB = new JButton("*");
        oneB = new JButton("1");
        twoB = new JButton("2");
        threeB = new JButton("3");
        subtractB = new JButton("-");
        zeroB = new JButton("0");
        dotB = new JButton(".");
        equalsB = new JButton("=");
        addB = new JButton("+");

        /*JPanel dataPanel = new JPanel();
        JPanel buttonPanel = new JPanel();

        FlowLayout flowCenter = new FlowLayout(FlowLayout.RIGHT);
        GridLayout aGrid = new GridLayout(4, 4);

        buttonPanel.setLayout(flowCenter);
        dataPanel.setLayout(aGrid);


        dataPanel.add(enterTextField);
        buttonPanel.add(sevenB);
        buttonPanel.add(eightB);
        buttonPanel.add(nineB);
        buttonPanel.add(divideB);
        buttonPanel.add(fourB);
        buttonPanel.add(fiveB);
        buttonPanel.add(sixB);
        buttonPanel.add(multiplyB);
        buttonPanel.add(oneB);
        buttonPanel.add(twoB);
        buttonPanel.add(threeB);
        buttonPanel.add(subtractB);
        buttonPanel.add(zeroB);
        buttonPanel.add(dotB);
        buttonPanel.add(equalsB);
        buttonPanel.add(addB);

        add(dataPanel, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.CENTER);*/

        //add(enterTextField);
        add(sevenB);
        add(eightB);
        add(nineB);
        add(divideB);
        add(fourB);
        add(fiveB);
        add(sixB);
        add(multiplyB);
        add(oneB);
        add(twoB);
        add(threeB);
        add(subtractB);
        add(zeroB);
        add(dotB);
        add(equalsB);
        add(addB);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);

    }

    public static void main(String[] args) {

        CalculatorGui calcu = new CalculatorGui();

    }

}

It runs but I need to put a text field right before those buttons (numbers). The text field should flow and will not be enlarged when the window is maximized (unlike the 4x4 buttons). I've tried JPanel (see comments) but it outputs a horrible design. P

Solution

Here you go, with some rules to follow while building GUI (rules):
Do not subclass AWT/Swing/X Components for application needs

import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class CalculatorGui {

    private static final int WIDTH = 250;
    private static final int HEIGHT = 250;
    private JTextField enterTextField;
    private JButton sevenB, eightB, nineB, divideB, fourB, fiveB, sixB, multiplyB, oneB, twoB, threeB, subtractB, zeroB, dotB, equalsB, addB;

    public CalculatorGui() {
        JFrame frame = new JFrame("Calculator");
        frame.setTitle("Calculator");
        frame.setSize(WIDTH, HEIGHT);

        JPanel buttonPanel = new JPanel(new GridLayout(4, 4));        
        enterTextField = new JTextField();       

        frame.add(enterTextField, BorderLayout.NORTH);

        sevenB = new JButton("7");
        eightB = new JButton("8");
        nineB = new JButton("9");
        divideB = new JButton("/");
        fourB = new JButton("4");
        fiveB = new JButton("5");
        sixB = new JButton("6");
        multiplyB = new JButton("*");
        oneB = new JButton("1");
        twoB = new JButton("2");
        threeB = new JButton("3");
        subtractB = new JButton("-");
        zeroB = new JButton("0");
        dotB = new JButton(".");
        equalsB = new JButton("=");
        addB = new JButton("+");

        buttonPanel.add(sevenB);
        buttonPanel.add(eightB);
        buttonPanel.add(nineB);
        buttonPanel.add(divideB);
        buttonPanel.add(fourB);
        buttonPanel.add(fiveB);
        buttonPanel.add(sixB);
        buttonPanel.add(multiplyB);
        buttonPanel.add(oneB);
        buttonPanel.add(twoB);
        buttonPanel.add(threeB);
        buttonPanel.add(subtractB);
        buttonPanel.add(zeroB);
        buttonPanel.add(dotB);
        buttonPanel.add(equalsB);
        buttonPanel.add(addB);

        frame.add(buttonPanel, BorderLayout.CENTER);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        CalculatorGui calcu = new CalculatorGui();
    }
}

I would suggest you to use WindowsBuilder Pro after a good manual practice with some layouts and components

Comments

[Admin]

Thank you very much, sir! I really appreciate your help. I'll work on WindowsBuilderPro as soon as I master Java. :) Thanks much!