Cześć czemu nie mogę wyświetlić ekrany klakulatora?
package Calculator;
import java.awt.BorderLayout;
import java.awt.DisplayMode;
import java.awt.Event;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class CalculatorPanel extends JPanel{
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;
display = new JButton("0");
display.setEnabled(false);
add(display, BorderLayout.NORTH);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
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);
}
private void addButton(String label, ActionListener listener) {
JButton button = new JButton(label);
button.addActionListener(listener);
panel.add(button);
}
private class InsertAction implements ActionListener{
@Override
public void actionPerformed(ActionEvent input) {
if(start){
display.setText("");
start = false;
}
display.setText(display.getText() + input);
}
}
private class CommandAction implements ActionListener{
@Override
public void actionPerformed(ActionEvent event) {
String command = event.getActionCommand();
if(start){
if (command.equals("-")) {
display.setText(command);
start = false;
}
else lastCommand = command;
}
else{
calualte(Double.parseDouble(display.getText()));
lastCommand = command;
start = true;
}
}
}
public void calualte(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);
}
}
package Calculator;
public class TestCal {
public static void main(String[] args) {
CalculatorPanel m = new CalculatorPanel();
m.setVisible(true);
}
}