main

package cz.sunnas.school.LS.hour05_swing;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.KeyStroke;

public class NumericPanel extends JFrame{

    private final JPanel numbs;
    private final JPanel display;

    public static void main( String[] args ) throws Exception {
        NumericPanel numPan = new NumericPanel();
    }

    public NumericPanel() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Numeric Panel");
        setMinimumSize(new Dimension(250, 300));
        setResizable(true);
        setLocationRelativeTo(null);
        setLayout(new BorderLayout());

        numbs = new JPanel(new GridLayout(4, 3, 25, 25));
        display = new JPanel(new FlowLayout(FlowLayout.CENTER));
        display.add(new Display(0, 50));

        numbs.add(new Button("0", 0, 60, 20));
        numbs.add(new Button("1", 1, 60, 20));
        numbs.add(new Button("2", 2, 60, 20));
        numbs.add(new Button("3", 3, 60, 20));
        numbs.add(new Button("4", 4, 60, 20));
        numbs.add(new Button("5", 5, 60, 20));
        numbs.add(new Button("6", 6, 60, 20));
        numbs.add(new Button("7", 7, 60, 20));
        numbs.add(new Button("8", 8, 60, 20));
        numbs.add(new Button("9", 9, 60, 20));
        numbs.add(new Button("E", 10, 60, 20));
        numbs.add(new Button("C", 11, 60, 20));


        add(display, BorderLayout.NORTH);
        add(numbs, BorderLayout.CENTER);

        setVisible(true);
        pack();
    }
}