Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.awt.GridLayout;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main {
    private static final float BTN_FONT_SIZE = 20f;
    private static final String[][] BTN_LABELS = { { "7", "8", "9", "-" }, { "4", "5", "6", "+" },
            { "1", "2", "3", "/" }, { "0", ".", " ", "=" } };
    private JPanel mainPanel = new JPanel();

    public Main() {
        int rows = BTN_LABELS.length;
        int cols = BTN_LABELS[0].length;
        int gap = 4;
        mainPanel.setBorder(BorderFactory.createEmptyBorder(gap, gap, gap, gap));
        mainPanel.setLayout(new GridLayout(rows, cols, gap, gap));
        for (String[] btnLabelRow : BTN_LABELS) {
            for (String btnLabel : btnLabelRow) {
                JButton btn = createButton(btnLabel);
                mainPanel.add(btn);
            }
        }
    }

    private JButton createButton(String btnLabel) {
        JButton button = new JButton(btnLabel);
        button.setFont(button.getFont().deriveFont(BTN_FONT_SIZE));
        return button;
    }

    public JComponent getMainComponent() {
        return mainPanel;
    }

    public static void main(String[] args) {
        Main mainPanel = new Main();

        JFrame frame = new JFrame("CalcEg");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(mainPanel.getMainComponent());
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }
}