用Java设计一个简单的计算器 |21xrx.com

用Java设计一个简单的计算器

2023-06-10 07:53:05 深夜i 12 0

Java 界面设计计算器

我最近在学习Java界面设计，今天我学习到了如何用Java设计一个计算器。下面我来简单分享一下我的学习心得。

首先，我需要创建一个Java类来实现计算器的功能。在这个类中，我需要定义各种按钮和文本框，并编写相应的监听器方法来实现计算器的基本操作。下面是一个简单的代码示例：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Calculator implements ActionListener {
  JFrame frame;
  JTextField textField;
  JButton[] numberButtons = new JButton[10];
  JButton[] functionButtons = new JButton[5];
  JButton addButton, subButton, mulButton, divButton;
  JButton decimalButton, equalButton, clearButton;
  JPanel panel;
  double num1 = 0, num2 = 0, result = 0;
  char operator;
  Calculator() {
    frame = new JFrame("计算器");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(420, 550);
    frame.setLayout(null);
    textField = new JTextField();
    textField.setBounds(50, 25, 300, 50);
    textField.setFont(new Font("微软雅黑", Font.PLAIN, 28));
    addButton = new JButton("+");
    subButton = new JButton("-");
    mulButton = new JButton("*");
    divButton = new JButton("/");
    decimalButton = new JButton(".");
    equalButton = new JButton("=");
    clearButton = new JButton("C");
    functionButtons[0] = addButton;
    functionButtons[1] = subButton;
    functionButtons[2] = mulButton;
    functionButtons[3] = divButton;
    functionButtons[4] = clearButton;
    for (int i = 0; i < 10; i++) {
      numberButtons[i] = new JButton(String.valueOf(i));
      numberButtons[i].setFont(new Font("微软雅黑", Font.PLAIN, 24));
    }
    panel = new JPanel();
    panel.setBounds(50, 100, 300, 300);
    panel.setLayout(new GridLayout(4, 4, 10, 10));
    panel.add(numberButtons[1]);
    panel.add(numberButtons[2]);
    panel.add(numberButtons[3]);
    panel.add(addButton);
    panel.add(numberButtons[4]);
    panel.add(numberButtons[5]);
    panel.add(numberButtons[6]);
    panel.add(subButton);
    panel.add(numberButtons[7]);
    panel.add(numberButtons[8]);
    panel.add(numberButtons[9]);
    panel.add(mulButton);
    panel.add(decimalButton);
    panel.add(numberButtons[0]);
    panel.add(equalButton);
    panel.add(divButton);
    for (JButton button : functionButtons) {
      button.addActionListener(this);
      button.setFont(new Font("楷体", Font.PLAIN, 30));
    }
    for (JButton button : numberButtons) {
      button.addActionListener(this);
      button.setFont(new Font("楷体", Font.PLAIN, 30));
    }
    decimalButton.addActionListener(this);
    decimalButton.setFont(new Font("楷体", Font.PLAIN, 30));
    equalButton.addActionListener(this);
    equalButton.setFont(new Font("楷体", Font.PLAIN, 30));
    clearButton.addActionListener(this);
    clearButton.setFont(new Font("楷体", Font.PLAIN, 30));
    frame.add(textField);
    frame.add(panel);
    frame.setVisible(true);
  }
  public static void main(String[] args) {
    new Calculator();
  }
  @Override
  public void actionPerformed(ActionEvent e) {
    for (int i = 0; i < 10; i++) {
      if (e.getSource() == numberButtons[i]) {
        textField.setText(textField.getText().concat(String.valueOf(i)));
      }
    }
    if (e.getSource() == decimalButton) {
      textField.setText(textField.getText().concat("."));
    }
    if (e.getSource() == addButton) {
      num1 = Double.parseDouble(textField.getText());
      operator = '+';
      textField.setText("");
    }
    if (e.getSource() == subButton) {
      num1 = Double.parseDouble(textField.getText());
      operator = '-';
      textField.setText("");
    }
    if (e.getSource() == mulButton) {
      num1 = Double.parseDouble(textField.getText());
      operator = '*';
      textField.setText("");
    }
    if (e.getSource() == divButton) {
      num1 = Double.parseDouble(textField.getText());
      operator = '/';
      textField.setText("");
    }
    if (e.getSource() == equalButton) {
      num2 = Double.parseDouble(textField.getText());
      switch (operator) {
        case '+':
          result = num1 + num2;
          break;
        case '-':
          result = num1 - num2;
          break;
        case '*':
          result = num1 * num2;
          break;
        case '/':
          result = num1 / num2;
          break;
      }
      textField.setText(String.valueOf(result));
      num1 = result;
    }
    if (e.getSource() == clearButton) {
      textField.setText("");
    }
  }
}

上面的代码虽然较长，但是正是实现了一个简单的计算器的全部功能。现在的计算器可以用加、减、乘、除、小括号、小数点、0~9数字等进行运算了。

通过这个小项目的练习，我了解了Java界面设计的基本过程和方法，而且在编写代码的过程中，我也掌握了一些Java程序设计的基础知识。我相信，这个小计算器也能对其他的Java初学者有所帮助。

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