Como faço para somar, dividir, multiplicar e colcoar o resultado no visor? ja fiz isso
[code]package gui;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Font;
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;
import javax.swing.JTextField;
public class Calculadora extends JFrame implements ActionListener {
JTextField display;
JButton bt_7 = new JButton("7");
JButton bt_8 = new JButton("8");
JButton bt_9 = new JButton("9");
JButton bt_dividir = new JButton("/");
JButton bt_4 = new JButton("4");
JButton bt_5 = new JButton("5");
JButton bt_6 = new JButton("6");
JButton bt_multiplicar = new JButton("*");
JButton bt_1 = new JButton("1");
JButton bt_2 = new JButton("2");
JButton bt_3 = new JButton("3");
JButton bt_subtrair = new JButton("-");
JButton bt_0 = new JButton("0");
JButton bt_ponto = new JButton(".");
JButton bt_somar = new JButton("+");
JButton bt_igual = new JButton("=");
public Calculadora() {
super("Calculadora");
Container n = new JPanel();
n.setLayout(new GridLayout(4,4, 5,5));
n.add(bt_7);
bt_7.addActionListener(this);
n.add(bt_8);
bt_8.addActionListener(this);
n.add(bt_9);
bt_9.addActionListener(this);
n.add(bt_dividir);
bt_dividir.addActionListener(this);
n.add(bt_4);
bt_4.addActionListener(this);
n.add(bt_5);
bt_5.addActionListener(this);
n.add(bt_6);
bt_6.addActionListener(this);
n.add(bt_multiplicar);
bt_multiplicar.addActionListener(this);
n.add(bt_1);
bt_1.addActionListener(this);
n.add(bt_2);
bt_2.addActionListener(this);
n.add(bt_3);
bt_3.addActionListener(this);
n.add(bt_subtrair);
n.add(bt_0);
bt_0.addActionListener(this);
n.add(bt_ponto);
bt_ponto.addActionListener(this);
n.add(bt_somar);
bt_somar.addActionListener(this);
n.add(bt_igual);
bt_igual.addActionListener(this);
display = new JTextField();
display.setFont(new Font("Serif", Font.PLAIN, 26));
Container c = getContentPane();
c.add(BorderLayout.NORTH, display);
c.add(BorderLayout.CENTER, n);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(300,300);
setVisible(true);
}
public static void main(String[] args) {
new Calculadora();
}
@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == bt_7) {
display.setText(display.getText()+"7");
} else if(e.getSource() == bt_8) {
display.setText(display.getText()+"8");
} else if(e.getSource() == bt_9) {
display.setText(display.getText()+"9");
} else if(e.getSource() == bt_dividir) {
display.setText(display.getText());
} else if(e.getSource() == bt_4) {
display.setText(display.getText()+"4");
} else if(e.getSource() == bt_5) {
display.setText(display.getText()+"5");
} else if(e.getSource() == bt_6) {
display.setText(display.getText()+"6");
} else if(e.getSource() == bt_multiplicar) {
display.setText(display.getText());
} else if(e.getSource() == bt_1) {
display.setText(display.getText()+"1");
} else if(e.getSource() == bt_2) {
display.setText(display.getText()+"2");
} else if(e.getSource() == bt_3) {
display.setText(display.getText()+"3");
} else if(e.getSource() == bt_subtrair) {
display.setText(display.getText());
} else if(e.getSource() == bt_0) {
display.setText(display.getText()+"0");
} else if(e.getSource() == bt_ponto) {
display.setText(display.getText());
} else if(e.getSource() == bt_ponto) {
display.setText(display.getText());
} else if(e.getSource() == bt_igual) {
display.setText(display.getText()+" = ");
}
}
}
[/code]