gitee仓库地址：Calculator: 简单计算器 (gitee.com)https://gitee.com/misaka10000/calculator

常量定义：

package com.wuzihao.calculator;import java.awt.*;public class Constant {public static final String NAME = "简单计算器";public static final int FRAME_W = 700;public static final int FRAME_H = 700;public static final int SCREEN_W = Toolkit.getDefaultToolkit().getScreenSize().width;public static final int SCREEN_H = Toolkit.getDefaultToolkit().getScreenSize().height;public static final int FRAME_X = (SCREEN_W - FRAME_W) / 2;public static final int FRAME_Y = (SCREEN_H - FRAME_H) / 2;}

 初始化程序:

public void init(){this.setTitle(Constant.NAME);this.setVisible(true);this.setSize(Constant.FRAME_W, Constant.FRAME_H);this.setLocation(Constant.FRAME_X, Constant.FRAME_Y);this.setLayout(new BorderLayout());this.setResizable(true);this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

计算器上层组件：

public void Component_North(){this.textField.setPreferredSize(new Dimension(650,50));this.jButton.setText("清空");this.jButton.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {textField.setText("");}});jPanel_north.add(textField);jPanel_north.add(jButton);this.add(jPanel_north,BorderLayout.NORTH);
}

计算器主体组件：

public void Component_Center(){String str = "123+456-789*0.=/";String regex = "[\\+\\-*=/]";this.jPanel_Center.setLayout(new GridLayout(4,4));for (int i = 0; i < 16; i++) {String substring = str.substring(i, i + 1);JButton jButton = new JButton();jButton.setText(substring);if(substring.matches(regex)){jButton.setFont(new Font("粗体",Font.BOLD,16));}jButton.addActionListener(this);jPanel_Center.add(jButton);}this.add(jPanel_Center,BorderLayout.CENTER);
}

监听方法实现：

@Override
public void actionPerformed(ActionEvent e) {String click = e.getActionCommand();if(".0123456789".contains(click)){this.textField.setText(textField.getText() + click);}else if(click.matches("[\\+\\-*/]{1}")){operator = click;firstInput = this.textField.getText();//保存当前的值this.textField.setText("");}else if(click.equals("=")){Double a = Double.valueOf(firstInput);Double b = Double.valueOf(textField.getText());Double result = null;switch(operator){case "+":result = a + b;break;case "-":result = a - b;break;case "*":result = a * b;break;case "/":result = a / b;break;}this.textField.setText(result.toString());}
}

页面效果展示：