Windows系统自带计算器的简单实现
1.布局方式：
整体采用BorderLayout布局方式，分为NORTH和SOUTH两部分。
NORTH部分为一个文本域（JTextArea）。
SOUTH部分采用GridLayout布局，分成6行4列，用来添加按钮。
2.代码结构
代码分为GUI界面的实现和事件的处理两部分。
GUI界面重点为按钮的添加（采用循环方式，可减少代码量）。
事件处理重点是准确获取事件发生源和文本域字符串的获取和设置。
3.代码实现
GUI界面
package com.calculator.exer1; import javax.swing.*; import java.awt.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class Calculator extends JFrame { JButton jb; Calculator(){ super("计算器"); setResizable(false); //设置窗口尺寸不能改变 // setSize(365,650); // setLocation(1000,50); setBounds(1000,50,365,650); surface(); setVisible(true); } public void surface(){ setLayout(new BorderLayout()); //设置整体布局为BorderLayout //NORTH部分 JPanel topPanel = new JPanel(); JTextArea jt = new JTextArea("0",5,22); jt.setFont(new Font("宋体",Font.BOLD,30)); jt.setEditable(false); topPanel.add(jt); add(topPanel,BorderLayout.NORTH); //SOUTH部分 JPanel bottomPanel = new JPanel(); bottomPanel.setLayout(new GridLayout(6,4,6,6)); String[] strs = { "%","CE","C","Del", "1/x","x²","√x","/", "7","8","9","*", "4","5","6","-", "1", "2","3","+", "+/_","0",".","=" }; Event event = new Event(jt); //监听器的创建 for(int i =0;i < strs.length; i++){ if(strs[i].equals("=")){ jb = new JButton(strs[i]); jb.setBackground(Color.blue); //设置背景颜色 jb.setForeground(Color.white); //设置字体颜色 jb.setFont(new Font("宋体",Font.BOLD,30));//设置字体参数 bottomPanel.add(jb); jb.addActionListener(event); }else{ jb = new JButton(strs[i]); jb.setBackground(Color.white); jb.setFont(new Font("宋体",Font.BOLD,20)); bottomPanel.add(jb); jb.addActionListener(event); } } add(bottomPanel); } public static void main(String[] args) { new Calculator(); } }
事件处理
package com.calculator.exer1; import javax.swing.*; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; public class Event implements ActionListener { JTextArea jt = new JTextArea(); StringBuffer sb = new StringBuffer(); Event(JTextArea jt){ this.jt = jt; } @Override public void actionPerformed(ActionEvent e) { String command = e.getActionCommand(); //返回与此动作相关的命令字符串。 String temp = jt.getText(); switch (command){ case "1": case "2": case "3": case "4": case "5": case "6": case "7": case "8": case "9": case "0": case "+": case "-": case "*": case "/": case ".": sb.append(command); jt.setText(sb.toString()); break; case "%": case "CE": case "C": sb.setLength(0); jt.setText("0"); break; case "Del": sb.deleteCharAt(sb.length()-1); jt.setText(temp.substring(0,temp.length()-1)); //返回该字符串的子字符串(去除原字符串尾部的一位，从而达到删除最后一位的目的) break; case "1/x": double ans1 = Double.valueOf(jt.getText()); jt.setText(String.valueOf(1 / ans1)); sb.setLength(0); break; case "x²": double ans2 = Double.valueOf(jt.getText()); jt.setText(String.valueOf(Math.pow(ans2,2))); sb.setLength(0); break; case "√x": double ans3 = Double.valueOf(jt.getText()); jt.setText(String.valueOf(Math.pow(ans3,0.5))); sb.setLength(0); break; case "=": if (temp.contains("+")) { String[] string = temp.split("\\+"); //分隔字符串 double num1 = Double.valueOf(string[0]); double num2 = Double.valueOf(string[1]); jt.setText(String.valueOf(num1 + num2)); sb.setLength(0); } else if (temp.contains("-")) { String[] string = temp.split("-"); double num1 = Double.valueOf(string[0]); double num2 = Double.valueOf(string[1]); jt.setText(String.valueOf(num1 - num2)); sb.setLength(0); } else if (temp.contains("*")) { String[] string = temp.split("\\*"); double num1 = Double.valueOf(string[0]); double num2 = Double.valueOf(string[1]); jt.setText(String.valueOf(num1 * num2)); sb.setLength(0); } else if (temp.contains("/")) { String[] string = temp.split("\\/"); double num1 = Double.valueOf(string[0]); double num2 = Double.valueOf(string[1]); jt.setText(String.valueOf(num1 / num2)); sb.setLength(0); } break; } } }
4.最终呈现
