Temat: Java "kalkulator"

/**
 * Write a description of class test2 here.
 * 
 * @author (your name) 
 * @version (a version number or a date)
 */
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;


public class Exercise3 extends JFrame implements ActionListener
{
    JButton jbtnA;
    JButton jbtnB;
    TextField ptextf;
    JTextField ptexts;
    TextArea ptar;
    JTextArea jtAreaOutput;
    String newline = "\n";
    String texte = "";
    
    Exercise3() 
    {
        JFrame jfrm = new JFrame ("Komponenty GraphicsUserInterface w Javie");
        jfrm.setLayout(null);
        jfrm.setSize(420, 450);
        jfrm.setLocation(100, 130);
        jfrm.setVisible(true);
        
        Label etykieta = new Label ("Etykieta");
        etykieta.setBounds(60,30,50,15);
        jfrm.add(etykieta);
        
        /*TextField pt = new TextField ("Pole tekstowe", 20);
        *pt.setBounds (40,65,100,20);
        *jfrm.add(pt);
        
        *Panel p = new Panel();
        *Choice c = new Choice();
        *c.add("Lista rozwijana");
        *c.add("Opcja_2");
        *c.add("Opcja_3");
        *p.add(c);
        *p.setBounds (20,260,110,90);
        *jfrm.add(p);
        
        *Panel p1 = new Panel ();
        *p1.add(new Label("Pola wyboru"));
        *p1.add(new Checkbox("Opcja_1"));
        *p1.add(new Checkbox("Opcja_2"));
        *p1.setBounds(70,180,230,25);
        *jfrm.add(p1);
        
        *Panel p2=new Panel();
        *p2.add (new Label ("Pola opcji"));
        *CheckboxGroup popcji = new CheckboxGroup ();
        *Checkbox Opcja_1;
        *Checkbox Opcja_2;
        *p2.add(Opcja_1 = new Checkbox ("Opcja_1", popcji, true));
        *p2.add(Opcja_2 = new Checkbox ("Opcja_2", popcji, false));
        *p2.setBounds(70,230,230,25);
        *jfrm.add(p2);
        */
       
        Panel panel1 = new Panel();
        Button jbtnA = new Button ("+");
        panel1.add(jbtnA);
        panel1.setBounds(180,290,30,30);
        jfrm.add (panel1);
        jbtnA.addActionListener(this);
        
        JButton jbtnB= new  JButton ("Zamknij");
        add(jbtnB);
        jbtnB.setBounds(130,350,130,30);
        jbtnB.addActionListener(this);
        jfrm.add(jbtnB);
        
        ptextf = new TextField (20);
        ptextf.addActionListener(this);
        ptextf.setBounds (30,135,150,30);
        jfrm.add(ptextf);
        
        ptexts = new JTextField (20);
        ptexts.addActionListener(this);
        ptexts.setEditable(false);
        ptexts.setBounds (220,135,150,30);
        jfrm.add(ptexts);
        
    }
    
    public void actionPreformed (ActionEvent evt)
    {
        String ac=evt.getActionCommand();
        
        if (ac.equals ("Zamknij"))
        {
            System.out.println("Zamknieto program");
            System.exit(0);
        }
        
        else if (ac.equals("+"))
        {
            String text2=ptextf.getText();
            int a = Integer.parseInt("1234");
            int b =a+a;
            texte = Integer.toString(b);
            ptexts.setText(texte);
       
        }
        
        else
        {
            String text1=ptextf.getText();
            ptexts.setText(text1);
             ptar.setText (text1 + newline);
             ptextf.selectAll();
            }
        }
        
        public static void main (String [] args)
        {
            Exercise3 PanelDemo = new Exercise3();
            PanelDemo.pack();
            PanelDemo.addWindowListener(new WindowAdapter()
            {
                public void windowClosing (WindowEvent e)
                {
                    //System.exit(0);
                }
            });
            
            PanelDemo.setVisible(true);
    }
     public void actionPerformed(ActionEvent ae)
     {
         System.exit(0);
        }
        
}

public void actionPreformed (ActionEvent evt)
    {
        String ac=evt.getActionCommand();
        
        if (ac.equals ("Zamknij"))
        {
            System.out.println("Zamknieto program");
            System.exit(0);
        }
        
        else if (ac.equals("+"))
        {
            String text2=ptextf.getText();
            int a = Integer.parseInt("1234");
            int b =a+a;
            texte = Integer.toString(b);
            ptexts.setText(texte);
       
        }
        
        else
        {
            String text1=ptextf.getText();
            ptexts.setText(text1);
             ptar.setText (text1 + newline);
             ptextf.selectAll();
            }
        }