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用Java实现简单的计算器
2023-06-13 03:58:57 深夜i     --     --
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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