java高手帮忙加个东西
/**
@Java calculator, with grid layout
@date created 06/26/2007
*/
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator
{
public static void main(String[] args)
{
CalculatorFrame frame = new CalculatorFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
/**
A frame with a calculator panel.
*/
class CalculatorFrame extends JFrame
{
public CalculatorFrame()
{
setTitle( "Calculator ");
CalculatorPanel panel = new CalculatorPanel();
getContentPane().add(panel);
pack();
}
}
/**
A panel with calculator buttons and a result display.
*/
class CalculatorPanel extends JPanel
{
public CalculatorPanel()
{
setLayout(new BorderLayout());
result = 0;
lastCommand = "= ";
start = true;
// add the display
display = new JButton( "0 ");
display.setEnabled(false);
add(display, BorderLayout.NORTH);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
// add the buttons in a 4 x 4 grid
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);
}
/**
Adds a button to the center panel.
@param label the button label
@param listener the button listener
*/
private void addButton(String label, ActionListener listener)
{
JButton button = new JButton(label);
button.addActionListener(listener);
panel.add(button);
}
/**
This action inserts the button action string to the
end of the display text.
*/
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);
}
}
/**
This action executes the command that the button
action string denotes.
*/
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;
}
}
}
/**
Carries out the pending calculation.
@param x the value to be accumulated with the prior result.
*/
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);
}
private JButton display;
private JPanel panel;
private double result;
private String lastCommand;
private boolean start;
}
上面是一个小的计算器.帮忙加一个按钮,能让计算时分整数显示或带小数点显示2种模式,上面显示是带全带小数点的.分2个按钮实现也行.java考试的作业呀.帮忙改一下.谢谢.!
[解决办法]
呵呵
[解决办法]
给楼主实现了，请楼主结贴吧。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator
{
public static void main(String[] args)
{
CalculatorFrame frame = new CalculatorFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
/**
A frame with a calculator panel.
*/
class CalculatorFrame extends JFrame
{
public CalculatorFrame()
{
setTitle( "Calculator ");
CalculatorPanel panel = new CalculatorPanel();
getContentPane().add(panel);
pack();
}
}
/**
A panel with calculator buttons and a result display.
*/
class CalculatorPanel extends JPanel
{
public CalculatorPanel()
{
setLayout(new BorderLayout());
result = 0;
lastCommand = "= ";
start = true;
// add the display
display = new JButton( "0 ");
display.setEnabled(false);
add(display, BorderLayout.NORTH);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
// add the buttons in a 4 x 4 grid
panel = new JPanel();
panel.setLayout(new GridLayout(5, 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);
JButton button1 = new JButton( "整数显示 ");
panel.add(button1);
button1.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
display.setText(display.getText().substring(0,display.getText().indexOf( ". ")));
}
});
add(panel, BorderLayout.CENTER);
}
/**
Adds a button to the center panel.
@param label the button label
@param listener the button listener
*/
private void addButton(String label, ActionListener listener)
{
JButton button = new JButton(label);
button.addActionListener(listener);
panel.add(button);
}
/**
This action inserts the button action string to the
end of the display text.
*/
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);
}
}
/**
This action executes the command that the button
action string denotes.
*/
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;
}
}
}
/**
Carries out the pending calculation.
@param x the value to be accumulated with the prior result.
*/
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);
}
private JButton display;
private JPanel panel;
private double result;
private String lastCommand;
private boolean start;
}
[解决办法]
楼上的，你的程序有问题，自己好好跑跑
[解决办法]
精彩
[解决办法]
真是精彩，要我来写可写不到这么快啊
