我最近在学习Java编程 |21xrx.com

我最近在学习Java编程

2023-06-10 13:55:15 深夜i 9 0

Java 计算器 Swing库

我最近在学习Java编程，今天我想分享一个简单的Java计算器的代码。在我编写这个计算器时，我主要利用了Java中的Swing库来帮助构建GUI界面。下面是我的代码示例：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class SimpleCalculator implements ActionListener {
  JTextField textField;
  JButton[] buttons = new JButton[16];
  String[] buttonLabels = {"1", "2", "3", "+", "4", "5", "6", "-", "7", "8", "9", "*", ".", "0", "C", "/"};
  String firstNumber = "";
  String secondNumber = "";
  String operator = "";
  Double result = 0.0;
  public SimpleCalculator() {
    JFrame frame = new JFrame("简易计算器");
    frame.setLayout(new BorderLayout());
    frame.setSize(250, 300);
    frame.setLocationRelativeTo(null);
    textField = new JTextField();
    textField.setEditable(false);
    frame.add(textField, BorderLayout.NORTH);
    JPanel buttonPanel = new JPanel(new GridLayout(4, 4));
    for (int i = 0; i < 16; i++) {
      buttons[i] = new JButton(buttonLabels[i]);
      buttons[i].addActionListener(this);
      buttonPanel.add(buttons[i]);
    }
    frame.add(buttonPanel, BorderLayout.CENTER);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }
  public static void main(String[] args) {
    SimpleCalculator calculator = new SimpleCalculator();
  }
  public void actionPerformed(ActionEvent e) {
    String command = e.getActionCommand();
    switch (command) {
      case "C":
        firstNumber = "";
        secondNumber = "";
        operator = "";
        result = 0.0;
        textField.setText("");
        break;
      case "+":
      case "-":
      case "*":
      case "/":
        operator = command;
        firstNumber = textField.getText();
        textField.setText("");
        break;
      case "=":
        secondNumber = textField.getText();
        Double num1 = Double.parseDouble(firstNumber);
        Double num2 = Double.parseDouble(secondNumber);
        switch (operator) {
          case "+":
            result = num1 + num2;
            break;
          case "-":
            result = num1 - num2;
            break;
          case "*":
            result = num1 * num2;
            break;
          case "/":
            result = num1 / num2;
            break;
          default:
            break;
        }
        textField.setText(result.toString());
        break;
      default:
        textField.setText(textField.getText() + command);
        break;
    }
  }
}

通过这个代码，我学会了如何创建一个简单的Java计算器。我还学到了如何使用Swing库来构建GUI界面，如何使用ActionListener来捕获用户的动作并根据用户的输入来执行一系列操作。这个计算器可以帮助我更好地理解Java编程的基础知识，我可以用它来练习其他编程技能。

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