用Java实现简单的计算器 |21xrx.com

用Java实现简单的计算器

2023-06-13 03:58:57 深夜i 14 0

Java编程算术运算 GUI实现

文章：

在编程语言中，算术运算是一个基本的部分。在Java中实现简单的计算器是一种非常简单的方法，用于理解Java编程语言中算术运算的基本概念。为了实现这个计算器，我们需要创建一个Java类，它具有基本的GUI（图形用户界面）组件，例如文本框、按钮和标签，以便用户可以输入数字，并得出算术结果。

下面是一个基本的Java代码，用于实现一个简单的计算器：

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Calculator implements ActionListener {
  JTextField textField;
  JButton[] numberButtons = new JButton[10];
  JButton[] functionButtons = new JButton[5];
  JButton addButton, subtractButton, multiplyButton, divideButton;
  JButton decimalButton, equalButton, deleteButton, clearButton;
  JPanel panel;
  double num1, num2, result;
  int addClick = 0, subtractClick = 0, multiplyClick = 0, divideClick = 0;
  Calculator() {
    JFrame frame = new JFrame("Calculator");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(500, 500);
    frame.setLocationRelativeTo(null);
    textField = new JTextField();
    textField.setBounds(50, 25, 400, 50);
    textField.setEditable(false);
    addButton = new JButton("+");
    subtractButton = new JButton("-");
    multiplyButton = new JButton("*");
    divideButton = new JButton("/");
    decimalButton = new JButton(".");
    equalButton = new JButton("=");
    deleteButton = new JButton("Delete");
    clearButton = new JButton("Clear");
    functionButtons[0] = addButton;
    functionButtons[1] = subtractButton;
    functionButtons[2] = multiplyButton;
    functionButtons[3] = divideButton;
    functionButtons[4] = equalButton;
    for (int i = 0; i < 10; i++) {
      numberButtons[i] = new JButton(String.valueOf(i));
    }
    panel = new JPanel();
    panel.setBounds(50, 100, 400, 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(subtractButton);
    panel.add(numberButtons[7]);
    panel.add(numberButtons[8]);
    panel.add(numberButtons[9]);
    panel.add(multiplyButton);
    panel.add(decimalButton);
    panel.add(numberButtons[0]);
    panel.add(deleteButton);
    panel.add(divideButton);
    panel.add(clearButton);
    panel.add(equalButton);
    for (JButton button : functionButtons) {
      button.addActionListener(this);
      button.setFont(button.getFont().deriveFont(20.0f));
      button.setFocusable(false);
    }
    for (JButton button : numberButtons) {
      button.addActionListener(this);
      button.setFont(button.getFont().deriveFont(20.0f));
      button.setFocusable(false);
    }
    decimalButton.addActionListener(this);
    deleteButton.addActionListener(this);
    clearButton.addActionListener(this);
    frame.add(panel);
    frame.add(textField);
    frame.setLayout(null);
    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());
      textField.setText("");
      addClick = 1;
    }
    if (e.getSource() == subtractButton) {
      num1 = Double.parseDouble(textField.getText());
      textField.setText("");
      subtractClick = 1;
    }
    if (e.getSource() == multiplyButton) {
      num1 = Double.parseDouble(textField.getText());
      textField.setText("");
      multiplyClick = 1;
    }
    if (e.getSource() == divideButton) {
      num1 = Double.parseDouble(textField.getText());
      textField.setText("");
      divideClick = 1;
    }
    if (e.getSource() == equalButton) {
      num2 = Double.parseDouble(textField.getText());
      if (addClick > 0) {
        result = num1 + num2;
        addClick = 0;
      }
      if (subtractClick > 0)
        result = num1 - num2;
        subtractClick = 0;
      
      if (multiplyClick > 0) {
        result = num1 * num2;
        multiplyClick = 0;
      }
      if (divideClick > 0)
        result = num1 / num2;
        divideClick = 0;
      
      textField.setText(String.valueOf(result));
    }
    if (e.getSource() == clearButton) {
      textField.setText("");
    }
    if (e.getSource() == deleteButton) {
      String currentText = textField.getText();
      textField.setText("");
      for (int i = 0; i < currentText.length() - 1; i++) {
        textField.setText(textField.getText() + currentText.charAt(i));
      }
    }
  }
}

这个计算器GUI具有数字按钮，四个基本的算术运算符，一个小数点和一些功能按钮。当用户按下一个数字按钮时，数字将被输入到文本框中。当用户按下算术运算符时，计算器将记录运算符并清空文本框。然后，用户可以输入下一个数字或按=运算符进行计算。计算结果将显示在文本框中。

通过这个简单的Java代码，我们可以了解如何在Java中创建GUI，并在其中使用基本的算术运算符。

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