Java面向对象第2版代码.zip

Example10_8.java public class Example10_8 { public static void main(String args[]) { WindowOperation win=new WindowOperation(); win.setBounds(100,100,390,360); win.setTitle("简单计算器"); } } WindowOperation.java import java.awt.*; import javax.swing.*; public class WindowOperation extends JFrame { JTextField inputNumberOne,inputNumberTwo; JComboBox<String> choiceFuhao; JTextArea textShow; JButton button; OperatorListener operator; //监视ItemEvent事件的监视器 ComputerListener computer; //监视ActionEvent事件的监视器 public WindowOperation() { init(); setVisible(true); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } void init() { setLayout(new FlowLayout()); inputNumberOne = new JTextField(5); inputNumberTwo = new JTextField(5); choiceFuhao = new JComboBox<String>(); button = new JButton("计算"); choiceFuhao.addItem("选择运算符号:"); String [] a = {"+","-","*","/"}; for(int i=0;i<a.length;i++) { choiceFuhao.addItem(a[i]); } textShow = new JTextArea(9,30); operator = new OperatorListener(); computer = new ComputerListener(); operator.setJComboBox(choiceFuhao); operator.setWorkTogether(computer); computer.setJTextFieldOne(inputNumberOne); computer.setJTextFieldTwo(inputNumberTwo); computer.setJTextArea(textShow); choiceFuhao.addItemListener(operator); //choiceFuhao是事件源,operator是监视器 button.addActionListener(computer); //button是事件源,computer是监视器 add(inputNumberOne); add(choiceFuhao); add(inputNumberTwo); add(button); add(new JScrollPane(textShow)); } } OperatorListener.java import java.awt.event.*; import javax.swing.*; public class OperatorListener implements ItemListener { JComboBox<String> choice; ComputerListener workTogether; public void setJComboBox(JComboBox<String> box) { choice = box; } public void setWorkTogether(ComputerListener computer) { workTogether = computer; } public void itemStateChanged(ItemEvent e) { String fuhao = choice.getSelectedItem().toString(); workTogether.setFuhao(fuhao); } } ComputerListener.java import java.awt.event.*; import javax.swing.*; public class ComputerListener implements ActionListener { JTextField inputNumberOne,inputNumberTwo; JTextArea textShow; String fuhao; public void setJTextFieldOne(JTextField t) { inputNumberOne = t; } public void setJTextFieldTwo(JTextField t) { inputNumberTwo = t; } public void setJTextArea(JTextArea area) { textShow = area; } public void setFuhao(String s) { fuhao = s; } public void actionPerformed(ActionEvent e) { try { double number1 = Double.parseDouble(inputNumberOne.getText()); double number2 = Double.parseDouble(inputNumberTwo.getText()); double result = 0; if(fuhao.equals("+")) { result = number1+number2; } else if(fuhao.equals("-")) { result = number1-number2; } else if(fuhao.equals("*")) { result = number1*number2; } else if(fuhao.equals("/")) { result = number1/number2; } textShow.append(number1+" "+fuhao+" "+number2+" = "+result+"\n"); } catch(Exception exp) { textShow.append("\n请输入数字字符\n"); } } }