中用GUI编程实现计算器模拟

1、JAVA中用GUI编程实现计算器模拟摘 要:本文论述了用java对计算器程序进行需求分析、概要设计、详细设计，最后使用Java编程实现的全过程。设计GUI界面的计算器，用户可以通过鼠标依次输入参加计算的数值，进行加、减、乘、除及求负、取余等，主要用到的组件有框架、面板、文本框、按钮和菜单栏等。关键词：GUI 计算器 一.编程思想定义计算器类calculator，该类继承JFrame类并实现ActionListener接口。整体窗口采用边界布局，通过另外建立若干面板组件。North位置的面板上放置一个文本框，用于显示运算中的数据及结果；center位置放置两个按钮，分别用来返回原界面和清零。再用

2、GridLayout（网格布局）对数字控件和操作按钮进行布局。此外，单击任何一个按钮都会触发ActionEvent事件，要处理这些事件就必须实现ActionListener接口的actionPerformed方法。二程序代码如下import javax.swing.*;import javax.swing.event.*;import java.awt.*;.*;/变量设置如下/继承JFrame类并实现ActionListenter接口public class calculator extends JFrame implements ActionListenerJFrame frame;/数字

3、及操作按钮JButton num0,num1,num2,num3,num4,num5,num6,num7,num8,num9,Back,c;/运算按钮JButton plusButton,minusButton,multiplyButton,divideButton,residueButton,equalButton,changeButton,dotButton,sqrtButton,reciprocalButton;JMenu fileM;JMenuItem exitM,helpM;JTextField text;/状态变量boolean clicked=true;boolean clear

4、=true;int all=0;double previous;String fuhao;int first=1;/界面设计public calculator()setTitle("计算器");setSize(300,250);setLocation(400,400);text=new JTextField(25);text.setHorizontalAlignment(JTextField.LEFT);JPanel cp1=new JPanel();JPanel cp2=new JPanel();JPanel cp3=new JPanel();/设置整体布局getCont

5、entPane().add(cp1,"North");getContentPane().add(cp2,"Center");getContentPane().add(cp3,"South");cp1.setLayout(new GridLayout(1,1);cp2.setLayout(new GridLayout(1,2);cp3.setLayout(new GridLayout(5,4);plusButton=new JButton("+");/加minusButton=new JButton("-&

6、quot;);/减multiplyButton=new JButton("*");/乘divideButton=new JButton("/");/除residueButton=new JButton("%");/余数equalButton=new JButton("=");/等号changeButton=new JButton("+/-");/正负号切换dotButton=new JButton(".");/小数点sqrtButton=new JButton("s

7、qrt");/开方reciprocalButton=new JButton("1/x");/倒数/数字按钮num0=new JButton("0");num1=new JButton("1");num2=new JButton("2");num3=new JButton("3");num4=new JButton("4");num5=new JButton("5");num6=new JButton("6");num7=new

8、 JButton("7");num8=new JButton("8");num9=new JButton("9");cp1.add(text);text.setEditable(false);text.setBackground(Color.white);/监听设置Back=new JButton("Back");Back.addActionListener(this);c=new JButton("C");c.addActionListener(this); cp2.add(Back);cp2

9、.add(c);cp3.add(num7);num7.addActionListener(this);cp3.add(num8);num8.addActionListener(this);cp3.add(num9);num9.addActionListener(this);cp3.add(divideButton);divideButton.addActionListener(this);cp3.add(num4);num4.addActionListener(this);cp3.add(num5);num5.addActionListener(this);cp3.add(num6);num6

10、.addActionListener(this);cp3.add(multiplyButton);multiplyButton.addActionListener(this);cp3.add(num1);num1.addActionListener(this); cp3.add(num2);num2.addActionListener(this);cp3.add(num3);num3.addActionListener(this);cp3.add(minusButton);minusButton.addActionListener(this); cp3.add(num0);num0.addAc

11、tionListener(this);cp3.add(changeButton);changeButton.addActionListener(this);cp3.add(dotButton);dotButton.addActionListener(this);cp3.add(plusButton);plusButton.addActionListener(this);cp3.add(reciprocalButton);reciprocalButton.addActionListener(this);cp3.add(residueButton);residueButton.addActionL

12、istener(this);cp3.add(sqrtButton);sqrtButton.addActionListener(this);cp3.add(equalButton);equalButton.addActionListener(this);/添加菜单组件JMenuBar mainMenu= new JMenuBar();setJMenuBar(mainMenu);JMenu editMenu=new JMenu("文件");JMenu helpMenu=new JMenu("帮助");helpM= new JMenuItem("关于

13、");mainMenu.add(editMenu);mainMenu.add(helpMenu);helpMenu.add(helpM);helpM.addActionListener(this);fileM=new JMenu(" 文件");exitM=new JMenuItem(" 退出");fileM.addActionListener(this);exitM.addActionListener(this);editMenu.add(fileM); editMenu.add(exitM);setVisible(true);addWindo

14、wListener(new WindowDestroyer();/结束窗口 /响应动作代码 public void actionPerformed(ActionEvent e)if (first =1)text.setText("");first=0;Object temp=e.getSource();if (temp=exitM)System.exit(0);if (temp=helpM)JOptionPane.showMessageDialog(null,"请查看帮助文档","帮助",JOptionPane.INFORMATION

15、_MESSAGE);/退格if (temp= Back)String s=text.getText();text.setText("");for (int i=0;i<s.length()-1;i+)char a=s.charAt(i);text.setText(text.getText()+a);/清零if (temp=c)text.setText("0.");clear=true;first=1;if (temp=num0)/判断是否单击了符号位if (clear=false)text.setText("");text.se

16、tText(text.getText()+"0"); if (temp=num1)if (clear=false)text.setText("");text.setText(text.getText()+"1");clear=true;if (temp=num2)if (clear=false)text.setText("");text.setText(text.getText()+"2"); clear=true; if (temp=num3)if (clear=false)text.setT

17、ext("");text.setText(text.getText()+"3"); clear=true; if (temp=num4)if (clear=false)text.setText("");text.setText(text.getText()+"4");clear=true; if (temp=num5)if (clear=false)text.setText("");text.setText(text.getText()+"5"); clear=true; i

18、f (temp=num6)if (clear=false)text.setText("");text.setText(text.getText()+"6");clear=true; if (temp=num7)if (clear=false)text.setText("");text.setText(text.getText()+"7");clear=true; if (temp=num8)if (clear=false)text.setText("");text.setText(text.ge

19、tText()+"8"); clear=true; if (temp=num9)if (clear=false)text.setText("");text.setText(text.getText()+"9"); clear=true;/判断是否含有小数点 if (temp = dotButton) clicked=true; for (int i=0;i<text.getText().length();i+) if ('.'=text.getText().charAt(i) clicked = false; b

20、reak; if (clicked = true) text.setText(text.getText()+".");try if (temp=plusButton) previous=Double.parseDouble(text.getText(); fuhao="+" clear=false; if (temp=minusButton) previous=Double.parseDouble(text.getText(); fuhao="-" clear=false; if (temp=multiplyButton) previ

21、ous=Double.parseDouble(text.getText(); fuhao="*" clear=false; if (temp=divideButton) previous=Double.parseDouble(text.getText(); fuhao="/" clear=false; if (temp=equalButton) double next = Double.parseDouble(text.getText(); text.setText(""); if (fuhao ="+") tex

22、t.setText(previous + next +""); if (fuhao ="-") text.setText(previous - next +""); if (fuhao ="*") text.setText(previous * next +""); if (fuhao ="/") if (next=0) text.setText("除数不能为零"); else text.setText(previous + next +"&qu

23、ot;); if (fuhao ="%") text.setText(previous % next +""); clear=false; if (temp=sqrtButton) String s=text.getText();if (s.charAt(0)= '-')text.setText("负数不能开根号");elsetext.setText(Double.toString(java.lang.Math.sqrt(Double.parseDouble(text.getText();clear = false;

24、if (temp=reciprocalButton)if (text.getText().charAt(0)='0'&& text.getText().length()=1)text.setText("除数不能为零");elseboolean isDec = true;int i,j,k;String s=Double.toString(1/Double.parseDouble(text.getText();for (i=0;i<s.length();i+)if (s.charAt(i)='.')break;for (j

25、=i+1;j<s.length();j+)if (s.charAt(j)='0')isDec=false;break;if (isDec = true) String stemp = ""for (k=0;k<i;k+)stemp += s.charAt(k);text.setText(stemp); elsetext.setText(s); clear = false; if ( temp = residueButton) previous=Double.parseDouble(text.getText(); fuhao="%" clear=false; if ( temp = changeButton) boolean isNumber = true; String s = text.getText(); for (int i=0;i<s.length();i+) if (!(s.charAt(i)>= '0'&& s.charAt(i