生成一个java计算器的可视界面代码，自己输入运算数和运算符号

创建一个简单的Java GUI计算器需要使用Swing或JavaFX库。这里我会给出一个基于Swing的例子，因为它是Java的标准GUI库。请注意，这只是一个基本的示例，实际应用可能需要更复杂的错误处理和用户界面设计。

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

public class SimpleCalculator extends JFrame {

    private JTextField[] fields = new JTextField[4];
    private JButton[] buttons = new JButton[10];

    public SimpleCalculator() {
        // 设置窗口标题和大小
        setTitle("Simple Calculator");
        setSize(300, 300);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 创建输入框和按钮布局
        JPanel panel = new JPanel();
        for (int i = 0; i < 4; i++) {
            fields[i] = new JTextField();
            fields[i].setColumns(5);
            panel.add(fields[i]);
        }
        
        int buttonIndex = 0;
        for (String symbol : new String[]{"7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", "+", "="}) {
            buttons[buttonIndex++] = createButton(symbol, i % 4 == 0 ? ActionListenerType.INPUT : ActionListenerType.OP);
            panel.add(buttons[buttonIndex - 1]);
        }

        JButton clearBtn = new JButton("Clear");
        clearBtn.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                for (JTextField field : fields) {
                    field.setText("");
                }
            }
        });
        buttons[buttonIndex++] = clearBtn;
        panel.add(clearBtn);

        add(panel);
    }

    private JButton createButton(String symbol, ActionListenerType type) {
        JButton button = new JButton(symbol);
        button.addActionListener((ActionEvent e) -> {
            switch (type) {
                case INPUT:
                    JTextField targetField = fields[(int) e.getActionCommand().charAt(0) - '0'];
                    targetField.setText(targetField.getText() + symbol);
                    break;
                case OP:
                    JTextField leftField = fields[(int) e.getActionCommand().charAt(0) - '0'];
                    JTextField rightField = fields[(int) e.getActionCommand().charAt(1) - '0'];
                    double leftValue = Double.parseDouble(leftField.getText());
                    double rightValue = Double.parseDouble(rightField.getText());
                    double result = 0;
                    switch (e.getActionCommand()) {
                        case "+":
                            result = leftValue + rightValue;
                            break;
                        case "-":
                            result = leftValue - rightValue;
                            break;
                        case "*":
                            result = leftValue * rightValue;
                            break;
                        case "/":
                            if (rightValue != 0)
                                result = leftValue / rightValue;
                            else
                                JOptionPane.showMessageDialog(null, "Error: Division by zero is not allowed.");
                            break;
                    }
                    leftField.setText(Double.toString(result));
                    break;
            }
        });
        return button;
    }

    enum ActionListenerType {
        INPUT,
        OP
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            SimpleCalculator calculator = new SimpleCalculator();
            calculator.setVisible(true);
        });
    }
}

在这个例子中，我们创建了一个包含数字、操作符和清除按钮的简单计算器界面。用户可以输入数字，点击运算符按钮执行计算，结果会显示在相应的输入字段中。当点击"="按钮时，会尝试执行运算并更新结果。