用 Javafx编写一个能够进行四则运算的计算器放在一个 class 内计算器eclipse

在JavaFX中编写一个简单的四则运算计算器，可以创建一个`Calculator`类，该类包含各种静态方法来执行加、减、乘、除操作。下面是一个基本的实现示例：

import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class Calculator extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    @Override
    public void start(Stage primaryStage) {
        primaryStage.setTitle("简单计算器");

        Label display = new Label();
        GridPane grid = new GridPane();
        grid.setAlignment(Pos.CENTER);

        // 数字按钮
        for (int i = 0; i <= 9; i++) {
            Button button = new Button(Integer.toString(i));
            button.setOnAction(e -> {
                String input = display.getText() + button.getText();
                display.setText(input);
            });
            grid.add(button, i % 4, i / 4);
        }

        // 运算符按钮
        Button addButton = new Button("+");
        addButton.setOnAction(e -> add(display.getText()));
        grid.add(addButton, 3, 3);

        Button subtractButton = new Button("-");
        subtractButton.setOnAction(e -> subtract(display.getText()));
        grid.add(subtractButton, 0, 3);

        Button multiplyButton = new Button("*");
        multiplyButton.setOnAction(e -> multiply(display.getText()));
        grid.add(multiplyButton, 1, 3);

        Button divideButton = new Button("/");
        divideButton.setOnAction(e -> divide(display.getText()));
        grid.add(divideButton, 2, 3);

        // 清零按钮
        Button clearButton = new Button("C");
        clearButton.setOnAction(e -> display.setText(""));
        grid.add(clearButton, 0, 0);

        // 等于按钮
        Button equalsButton = new Button "=";
        equalsButton.setOnAction(e -> performCalculation(display.getText(), "=", display));
        grid.add(equalsButton, 3, 0);

        HBox buttonsRow = new HBox(grid);
        VBox root = new VBox(10, display, buttonsRow);
        Scene scene = new Scene(root, 300, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void add(String currentText) {
        double result = Double.parseDouble(currentText) + 1;
        display.setText(result + "");
    }

    private void subtract(String currentText) {
        double result = Double.parseDouble(currentText) - 1;
        display.setText(result + "");
    }

    private void multiply(String currentText) {
        double result = Double.parseDouble(currentText) * 2;
        display.setText(result + "");
    }

    private void divide(String currentText) {
        if (!currentText.isEmpty()) {
            try {
                double result = Double.parseDouble(currentText) / 2;
                display.setText(result + "");
            } catch (NumberFormatException e) {
                display.setText("错误，请输入数字");
            }
        }
    }

    private void performCalculation(String currentText, String operator, Label display) {
        if (currentText.isEmpty()) return;

        try {
            double num1 = Double.parseDouble(currentText);
            double num2 = calculateNextNumber(display.getText());
            switch (operator) {
                case "+":
                    display.setText(num1 + num2 + "");
                    break;
                case "-":
                    display.setText(num1 - num2 + "");
                    break;
                case "*":
                    display.setText(num1 * num2 + "");
                    break;
                case "/":
                    display.setText(num1 / num2 + "");
                    break;
                default:
                    throw new IllegalArgumentException("未知的运算符");
            }
        } catch (NumberFormatException e) {
            display.setText("错误，请输入数字");
        }
    }

    private double calculateNextNumber(String text) {
        int index = text.indexOf(".");
        if (index == -1) {
            return Double.parseDouble(text);
        } else {
            return Double.parseDouble(text.substring(0, index + 1));
        }
    }
}

这个例子展示了如何在一个JavaFX窗口上创建一个基础的计算器应用，包括数字按钮、运算符按钮以及清零和等于按钮。当用户点击等号按钮时，会执行相应的计算。