中用GUI編程實現計算器模擬

1、JAVA中用GUI編程實現計算器模擬摘 要:本文論述了用java對計算器程序進行需求分析、概要設計、詳細設計，最后使用Java編程實現的全過程。設計GUI界面的計算器，用戶可以通過鼠標依次輸入參加計算的數值，進行加、減、乘、除及求負、取余等，主要用到的組件有框架、面板、文本框、按鈕和菜單欄等。關鍵詞：GUI 計算器 一.編程思想定義計算器類calculator，該類繼承JFrame類并實現ActionListener接口。整體窗口采用邊界布局，通過另外建立若干面板組件。North位置的面板上放置一個文本框，用于顯示運算中的數據及結果；center位置放置兩個按鈕，分別用來返回原界面和清零。再用

2、GridLayout（網格布局）對數字控件和操作按鈕進行布局。此外，單擊任何一個按鈕都會觸發(fā)ActionEvent事件，要處理這些事件就必須實現ActionListener接口的actionPerformed方法。二程序代碼如下import javax.swing.*;import javax.swing.event.*;import java.awt.*;.*;/變量設置如下/繼承JFrame類并實現ActionListenter接口public class calculator extends JFrame implements ActionListenerJFrame frame;/數字

3、及操作按鈕JButton num0,num1,num2,num3,num4,num5,num6,num7,num8,num9,Back,c;/運算按鈕JButton plusButton,minusButton,multiplyButton,divideButton,residueButton,equalButton,changeButton,dotButton,sqrtButton,reciprocalButton;JMenu fileM;JMenuItem exitM,helpM;JTextField text;/狀態(tài)變量boolean clicked=true;boolean clear

4、=true;int all=0;double previous;String fuhao;int first=1;/界面設計public calculator()setTitle("計算器");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();/設置整體布局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;);/減multiplyButton=new JButton("*");/乘divideButton=new JButton("/");/除residueButton=new JButton("%");/余數equalButton=new JButton("=");/等號changeButton=new JButton("+/-");/正負號切換dotButton=new JButton(".");/小數點sqrtButton=new JButton("s

7、qrt");/開方reciprocalButton=new JButton("1/x");/倒數/數字按鈕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);/監(jiān)聽設置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);/添加菜單組件JMenuBar mainMenu= new JMenuBar();setJMenuBar(mainMenu);JMenu editMenu=new JMenu("文件");JMenu helpMenu=new JMenu("幫助");helpM= new JMenuItem("關于

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();/結束窗口 /響應動作代碼 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,"請查看幫助文檔","幫助",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)/判斷是否單擊了符號位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;/判斷是否含有小數點 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("除數不能為零"); 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("負數不能開根號");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("除數不能為零");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