package CalculatorAppletWithFrame;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JPanel;
/**
* Panel cu butoanele calculatorului si elementele pentru afisare a resultatului calcularii
* @author Dan
*
*/
public class CalculatorPanel extends JPanel
{
/**
*
*/
private static final long serialVersionUID = 1L;
private JButton display;
private JPanel panel;
private double result;
private String lastCommand;
private boolean start;
public CalculatorPanel()
{
setLayout(new BorderLayout());
result = 0;
lastCommand = "=";
start = true;
//Adaugarea elementului pentru afisarea resultatului
display= new JButton("0");
display.setEnabled(false);
add(display,BorderLayout.NORTH);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
//Adaugarea butoanelor 4x4
panel = new JPanel();
panel.setLayout(new GridLayout(4,4));
addButton("7",insert);
addButton("8",insert);
addButton("9",insert);
addButton("/",command);
addButton("4",insert);
addButton("5",insert);
addButton("6",insert);
addButton("*",command);
addButton("1",insert);
addButton("2",insert);
addButton("3",insert);
addButton("-",command);
addButton("0",insert);
addButton(".",insert);
addButton("=",command);
addButton("+",command);
add(panel,BorderLayout.CENTER);
}
/**
* Adaugarea butonului in panelul din centru
* @param label labelul pe buton
* @param listner litnerul ce activeaza butonul
*/
private void addButton(String label,ActionListener listner)
{
JButton button=new JButton(label);
button.addActionListener(listner);
panel.add(button);
}
/**
* La controlul evenimentului in linie,legata de buton se adauga la final textul.
*/
private class InsertAction implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
String input = event.getActionCommand();
if(start)
{
display.setText("");
start=false;
}
display.setText(display.getText()+input);
}
}
/**
* La controlul evenimentului se executa comanda care se indentifica dupa linie, legata cu butonul.
*/
private class CommandAction implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
String command = event.getActionCommand();
if(start)
{
if(command.equals("-"))
{
display.setText(command);
start=false;
}
else
lastCommand = command;
}
else
{
calculate(Double.parseDouble(display.getText()));
lastCommand = command;
start=true;
}
}
}
/**
* Executarea calcularii
*/
public void calculate(double x)
{
if(lastCommand.equals("+")) result += x;
else if (lastCommand.equals("-")) result -= x;
else if (lastCommand.equals("*")) result *= x;
else if (lastCommand.equals("/")) result /= x;
else if (lastCommand.equals("=")) result = x;
display.setText("" + result);
}
}