java计算器
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import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class CalculatorPanel extends JFrame{
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
{
public void actionPerformed(ActionEvent event)
{
String input=event.getActionCommand();
if(start)
{
display.setText("");
start=false;
}
display.setText(display.getText()+input);
}
}
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;
}
}
}
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);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame frame=new CalculatorPanel();
frame.setTitle("Calculate");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
import javax.swing.*;
import java.awt.event.*;
public class CalculatorPanel extends JFrame{
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
{
public void actionPerformed(ActionEvent event)
{
String input=event.getActionCommand();
if(start)
{
display.setText("");
start=false;
}
display.setText(display.getText()+input);
}
}
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;
}
}
}
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);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
JFrame frame=new CalculatorPanel();
frame.setTitle("Calculate");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
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