我用java实现计算器时，将键盘的退格键连接了按钮退格键，为什么我一按下键盘的退格键就会发出提示音，而按下退格按钮则不会，怎么解决

这是因为键盘的退格键和按钮的退格键的事件处理方式不同。键盘的退格键在处理事件时会触发系统提示音，而按钮的退格键则不会。要解决这个问题，你可以在按钮的事件处理方法中屏蔽掉系统提示音，可以使用如下代码：

button.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        // 屏蔽系统提示音
        e.consume();
        // 处理退格事件
        // ...
    }
});

在事件处理方法中使用 `e.consume()` 可以屏蔽事件的后续处理，包括系统提示音。这样就可以避免在按下按钮退格键时发出系统提示音的问题。

相关问题

用Java实现实现计算器，backspace为退格键，单目运算符：+/-，1/x，sqrt，%双目运算符：+，-，*，/。CE为清除，C为清除全部，M+，M-,MR,MC,M+表示将当前显示的存储数值进行加法运算

以下是一个简单的Java计算器实现，包括上述要求的功能：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Calculator extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;

    private JButton display;
    private JButton backspace;
    private JButton plusMinus;
    private JButton reciprocal;
    private JButton squareRoot;
    private JButton percent;
    private JButton clearEntry;
    private JButton clearAll;
    private JButton memoryPlus;
    private JButton memoryMinus;
    private JButton memoryRecall;
    private JButton memoryClear;
    private JButton divide;
    private JButton multiply;
    private JButton subtract;
    private JButton add;
    private JButton equals;

    private double memory = 0;
    private double currentNumber = 0;
    private double result = 0;
    private char lastOperator;

    private boolean startNewNumber = true;

    public Calculator() {
        super("Calculator");

        display = new JButton("0");
        display.setEnabled(false);
        backspace = new JButton("Backspace");
        backspace.addActionListener(this);
        plusMinus = new JButton("+/-");
        plusMinus.addActionListener(this);
        reciprocal = new JButton("1/x");
        reciprocal.addActionListener(this);
        squareRoot = new JButton("sqrt");
        squareRoot.addActionListener(this);
        percent = new JButton("%");
        percent.addActionListener(this);
        clearEntry = new JButton("CE");
        clearEntry.addActionListener(this);
        clearAll = new JButton("C");
        clearAll.addActionListener(this);
        memoryPlus = new JButton("M+");
        memoryPlus.addActionListener(this);
        memoryMinus = new JButton("M-");
        memoryMinus.addActionListener(this);
        memoryRecall = new JButton("MR");
        memoryRecall.addActionListener(this);
        memoryClear = new JButton("MC");
        memoryClear.addActionListener(this);
        divide = new JButton("/");
        divide.addActionListener(this);
        multiply = new JButton("*");
        multiply.addActionListener(this);
        subtract = new JButton("-");
        subtract.addActionListener(this);
        add = new JButton("+");
        add.addActionListener(this);
        equals = new JButton("=");
        equals.addActionListener(this);

        JPanel buttonPanel = new JPanel(new GridLayout(5, 4, 5, 5));
        buttonPanel.add(memoryClear);
        buttonPanel.add(memoryRecall);
        buttonPanel.add(memoryMinus);
        buttonPanel.add(memoryPlus);
        buttonPanel.add(percent);
        buttonPanel.add(squareRoot);
        buttonPanel.add(reciprocal);
        buttonPanel.add(divide);
        buttonPanel.add(7);
        buttonPanel.add(8);
        buttonPanel.add(9);
        buttonPanel.add(multiply);
        buttonPanel.add(4);
        buttonPanel.add(5);
        buttonPanel.add(6);
        buttonPanel.add(subtract);
        buttonPanel.add(1);
        buttonPanel.add(2);
        buttonPanel.add(3);
        buttonPanel.add(add);
        buttonPanel.add(plusMinus);
        buttonPanel.add(0);
        buttonPanel.add(".");
        buttonPanel.add(equals);
        buttonPanel.add(clearEntry);
        buttonPanel.add(clearAll);
        buttonPanel.add(backspace);

        JPanel displayPanel = new JPanel(new BorderLayout());
        displayPanel.add(display, BorderLayout.CENTER);

        add(displayPanel, BorderLayout.NORTH);
        add(buttonPanel, BorderLayout.CENTER);

        setSize(300, 300);
        setLocationRelativeTo(null);
        setResizable(false);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    }

    private void handleNumberInput(int number) {
        if (startNewNumber) {
            display.setText(String.valueOf(number));
            currentNumber = number;
            startNewNumber = false;
        } else {
            String current = display.getText();
            if (current.equals("0")) {
                display.setText(String.valueOf(number));
            } else {
                display.setText(current + number);
            }
            currentNumber = Double.parseDouble(display.getText());
        }
    }

    private void handleOperatorInput(char operator) {
        if (startNewNumber) {
            lastOperator = operator;
        } else {
            switch (lastOperator) {
                case '+':
                    result += currentNumber;
                    break;
                case '-':
                    result -= currentNumber;
                    break;
                case '*':
                    result *= currentNumber;
                    break;
                case '/':
                    result /= currentNumber;
                    break;
                case '%':
                    result %= currentNumber;
                    break;
                default:
                    result = currentNumber;
                    break;
            }
            display.setText(String.valueOf(result));
            currentNumber = result;
            startNewNumber = true;
            lastOperator = operator;
        }
    }

    public void actionPerformed(ActionEvent e) {
        Object source = e.getSource();
        if (source == backspace) {
            String current = display.getText();
            if (current.length() > 1) {
                display.setText(current.substring(0, current.length() - 1));
                currentNumber = Double.parseDouble(display.getText());
            } else {
                display.setText("0");
                currentNumber = 0;
                startNewNumber = true;
            }
        } else if (source == plusMinus) {
            currentNumber = -currentNumber;
            display.setText(String.valueOf(currentNumber));
        } else if (source == reciprocal) {
            currentNumber = 1 / currentNumber;
            display.setText(String.valueOf(currentNumber));
        } else if (source == squareRoot) {
            currentNumber = Math.sqrt(currentNumber);
            display.setText(String.valueOf(currentNumber));
        } else if (source == percent) {
            handleOperatorInput('%');
        } else if (source == clearEntry) {
            display.setText("0");
            currentNumber = 0;
            startNewNumber = true;
        } else if (source == clearAll) {
            result = 0;
            lastOperator = ' ';
            display.setText("0");
            currentNumber = 0;
            startNewNumber = true;
        } else if (source == memoryPlus) {
            memory += currentNumber;
        } else if (source == memoryMinus) {
            memory -= currentNumber;
        } else if (source == memoryRecall) {
            currentNumber = memory;
            display.setText(String.valueOf(currentNumber));
        } else if (source == memoryClear) {
            memory = 0;
        } else if (source == divide) {
            handleOperatorInput('/');
        } else if (source == multiply) {
            handleOperatorInput('*');
        } else if (source == subtract) {
            handleOperatorInput('-');
        } else if (source == add) {
            handleOperatorInput('+');
        } else if (source == equals) {
            switch (lastOperator) {
                case '+':
                    result += currentNumber;
                    break;
                case '-':
                    result -= currentNumber;
                    break;
                case '*':
                    result *= currentNumber;
                    break;
                case '/':
                    result /= currentNumber;
                    break;
                case '%':
                    result %= currentNumber;
                    break;
                default:
                    result = currentNumber;
                    break;
            }
            display.setText(String.valueOf(result));
            currentNumber = result;
            startNewNumber = true;
            lastOperator = ' ';
        } else {
            handleNumberInput((Integer) source);
        }
    }

    public static void main(String[] args) {
        Calculator calculator = new Calculator();
        calculator.setVisible(true);
    }

}

这个实现使用了Java的Swing GUI库来创建一个带有按钮和文本框的窗口，并在按钮上添加了相应的事件处理程序来实现计算器的功能。

使用java编写以下程序自行设计一个计算器，完成简单计算器功能，如下图。 特别需要注意的几个操作： （1）小数点的处理 （2）连加，连减等连续运算 （3）清空（C键）和清零（CE键）的区别 （4）后退键的实现（采用两种方式实现：自己编写；调用键盘退格键） 界面可自行设计，不必拘泥于现有计算器。

以下是使用Java编写的简单计算器程序：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class Calculator extends JFrame implements ActionListener {
    private JTextField display;
    private JButton[] buttons;
    private String[] buttonLabels = {"C", "CE", "<-", "/", "7", "8", "9", "*", "4", "5", "6", "-", "1", "2", "3", "+", "+/-", "0", ".", "="};
    private boolean isDecimal = false; // 是否输入了小数点
    private boolean isOperator = false; // 是否输入了操作符
    private boolean isEqual = false; // 是否已经按下了等号
    private String currentText = ""; // 当前输入的文本
    private String operator = ""; // 当前的操作符
    private double result = 0.0; // 计算结果

    public Calculator() {
        super("Calculator");

        // 设置窗口大小
        setSize(300, 400);

        // 设置布局
        setLayout(new BorderLayout());

        // 创建文本框
        display = new JTextField();
        display.setEditable(false);
        add(display, BorderLayout.NORTH);

        // 创建按钮面板
        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new GridLayout(5, 4, 5, 5));

        // 创建按钮
        buttons = new JButton[buttonLabels.length];
        for (int i = 0; i < buttonLabels.length; i++) {
            buttons[i] = new JButton(buttonLabels[i]);
            buttons[i].addActionListener(this);
            buttonPanel.add(buttons[i]);
        }

        // 添加按钮面板
        add(buttonPanel, BorderLayout.CENTER);

        // 设置窗口可见
        setVisible(true);
    }

    // 处理按钮事件
    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();

        // 清空
        if (command.equals("C")) {
            display.setText("");
            isDecimal = false;
            isOperator = false;
            isEqual = false;
            currentText = "";
            operator = "";
            result = 0.0;
        }
        // 清零
        else if (command.equals("CE")) {
            display.setText("");
            isDecimal = false;
            isOperator = false;
            currentText = "";
        }
        // 后退
        else if (command.equals("<-")) {
            String text = display.getText();
            if (text.length() > 0) {
                text = text.substring(0, text.length() - 1);
                display.setText(text);
            }
        }
        // 数字和小数点
        else if (command.equals("0") || command.equals("1") || command.equals("2") || command.equals("3") || command.equals("4") || command.equals("5") || command.equals("6") || command.equals("7") || command.equals("8") || command.equals("9") || command.equals(".")) {
            if (isEqual) {
                display.setText("");
                isEqual = false;
            }
            if (command.equals(".")) {
                if (!isDecimal) {
                    isDecimal = true;
                } else {
                    return;
                }
            }
            display.setText(display.getText() + command);
        }
        // 操作符
        else if (command.equals("+") || command.equals("-") || command.equals("*") || command.equals("/")) {
            if (isOperator) {
                calculate();
            }
            operator = command;
            result = Double.parseDouble(display.getText());
            isDecimal = false;
            isOperator = true;
            isEqual = false;
        }
        // 取反
        else if (command.equals("+/-")) {
            String text = display.getText();
            if (text.length() > 0 && !text.equals("0")) {
                if (text.startsWith("-")) {
                    text = text.substring(1);
                } else {
                    text = "-" + text;
                }
                display.setText(text);
            }
        }
        // 计算结果
        else if (command.equals("=")) {
            calculate();
            operator = "";
            isDecimal = false;
            isOperator = false;
            isEqual = true;
        }
    }

    // 计算结果
    private void calculate() {
        double num = Double.parseDouble(display.getText());
        if (operator.equals("+")) {
            result += num;
        } else if (operator.equals("-")) {
            result -= num;
        } else if (operator.equals("*")) {
            result *= num;
        } else if (operator.equals("/")) {
            result /= num;
        }
        display.setText(Double.toString(result));
        isDecimal = false;
        isOperator = false;
    }

    public static void main(String[] args) {
        new Calculator();
    }
}

该程序使用了Swing库来创建界面和按钮，并通过实现ActionListener接口来处理按钮事件。在处理按钮事件时，程序根据按钮的文本来执行相应的操作，例如清空、清零、后退、输入数字和小数点、输入操作符、取反和计算结果。程序还使用了一些布尔变量来记录当前的状态，例如是否输入了小数点、是否输入了操作符和是否已经按下了等号。在计算结果时，程序使用了一个result变量来保存中间结果，并根据当前的操作符来执行相应的运算。