用Java语言模拟简单的计算器.doc

package std1;import java.awt.BorderLayout;import java.awt.Color;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.util.Scanner;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JPanel;import javax.swing.JTextField;public class Computer extends JFrame implements ActionListener private String first; /把运算数定义成字符窜private boolean hasFirst; /第一个数是否存在private String second;private boolean hasSecond;private String sign; /运算符private boolean hasSign;private JTextField result; /文本框内容private JButton button;public Computer() clear();initJFrame();/初始化界面JFrameOverridepublic void actionPerformed(ActionEvent e) String s = e.getActionCommand(); /这个方法得到按钮上的内容。String num = 0123456789.;/定义一个除了运算符的字符序列。if(s.equals(=)/按位与，是求交集if(hasFirst & hasSecond & hasSign)getResult();clear();elseresult.setText(0.0);else if(num.contains(s)/如果s在num中包含着，即s是1,2,3,4,5,6,7,8,9,.if(!hasFirst)first = first+s;result.setText(first);elsehasSecond = true;second = second+s;result.setText(second);else if(s.equals(C)/C的功能，是清空文本框clear();result.setText(0.0);else/这种情况下，s是运算符+-*/hasFirst = true;/第一个运算数输完后，hasFirst为truehasSign = true;/运算符也输进去了。sign = s;/进行运算private void getResult() if(sign.equals(+)result.setText(Double.parseDouble(first)+Double.parseDouble(second)+ ); if(sign.equals(-) result.setText(Double.parseDouble(first)-Double.parseDouble(second)+ ); if(sign.equals(*) result.setText(Double.parseDouble(first)*Double.parseDouble(second)+ ); /parseDouble(String s)throws NumberFormatException返回一个新的 double值，该值 /被初始化为用指定 String 表示的值，这与 Double 类的 valueOf 方法一样加是为了是结果变成一个字符窜 if(sign.equals(/) result.setText(Double.parseDouble(first)/Double.parseDouble(second)+ ); /把属性的值private void clear() hasSecond = false;hasFirst = false;hasSign = false;first = new String();second = new String();sign = new String();/初始化界面private void initJFrame() JPanel panel1 = new JPanel();panel1.setLayout(new BorderLayout();result = new JTextField(10);result.setText(0.0);panel1.add(result);result.addActionListener(this); /监听文本框button = new JButton(C);button.setForeground(Color.BLUE);button.addActionListener(this);panel1.add(button, BorderLayout.EAST);button.addActionListener(this); /监听Cthis.add(panel1, BorderLayout.NORTH);JPanel panel2 = new JPanel();panel2.setLayout(new GridLayout(4, 4);String component = 1, 2, 3, +, 4, 5, 6, -, 7,8, 9, *, 0, ., =, / ;for (int i = 0;i component.length;i+) JButton button1 = new JButton(componenti);button1.addActionListener(this);/监听按钮panel2.add(button1);this.add(panel2);this.setLocation(200, 200);this.pack();this.setTi