javafx编写一个计算加减乘除的代码

下面是一个简单的 JavaFX 计算器示例，实现加、减、乘、除四种基本运算：

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.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class Calculator extends Application {

    private TextField tfNumber1 = new TextField();
    private TextField tfNumber2 = new TextField();
    private TextField tfResult = new TextField();

    @Override
    public void start(Stage primaryStage) {
        GridPane gridPane = new GridPane();
        gridPane.setAlignment(Pos.CENTER);
        gridPane.setHgap(5);
        gridPane.setVgap(5);

        Label lbNumber1 = new Label("Number 1:");
        Label lbNumber2 = new Label("Number 2:");
        Label lbResult = new Label("Result:");

        Button btnAdd = new Button("+");
        btnAdd.setOnAction(e -> add());
        Button btnSubtract = new Button("-");
        btnSubtract.setOnAction(e -> subtract());
        Button btnMultiply = new Button("*");
        btnMultiply.setOnAction(e -> multiply());
        Button btnDivide = new Button("/");
        btnDivide.setOnAction(e -> divide());

        tfNumber1.setAlignment(Pos.BASELINE_RIGHT);
        tfNumber2.setAlignment(Pos.BASELINE_RIGHT);
        tfResult.setAlignment(Pos.BASELINE_RIGHT);
        tfResult.setEditable(false);

        gridPane.add(lbNumber1, 0, 0);
        gridPane.add(tfNumber1, 1, 0);
        gridPane.add(lbNumber2, 0, 1);
        gridPane.add(tfNumber2, 1, 1);
        gridPane.add(btnAdd, 0, 2);
        gridPane.add(btnSubtract, 1, 2);
        gridPane.add(btnMultiply, 0, 3);
        gridPane.add(btnDivide, 1, 3);
        gridPane.add(lbResult, 0, 4);
        gridPane.add(tfResult, 1, 4);

        Scene scene = new Scene(gridPane, 300, 200);
        primaryStage.setTitle("Calculator");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void add() {
        double number1 = Double.parseDouble(tfNumber1.getText());
        double number2 = Double.parseDouble(tfNumber2.getText());
        double result = number1 + number2;
        tfResult.setText(String.format("%.2f", result));
    }

    private void subtract() {
        double number1 = Double.parseDouble(tfNumber1.getText());
        double number2 = Double.parseDouble(tfNumber2.getText());
        double result = number1 - number2;
        tfResult.setText(String.format("%.2f", result));
    }

    private void multiply() {
        double number1 = Double.parseDouble(tfNumber1.getText());
        double number2 = Double.parseDouble(tfNumber2.getText());
        double result = number1 * number2;
        tfResult.setText(String.format("%.2f", result));
    }

    private void divide() {
        double number1 = Double.parseDouble(tfNumber1.getText());
        double number2 = Double.parseDouble(tfNumber2.getText());
        if (number2 == 0) {
            tfResult.setText("Error: Division by zero");
        } else {
            double result = number1 / number2;
            tfResult.setText(String.format("%.2f", result));
        }
    }

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

该程序使用 GridPane 布局，包含三个文本框（用于输入两个操作数和显示结果）和四个按钮（用于执行加、减、乘、除四种基本运算）。每个按钮都有一个对应的操作方法，用于执行相应的运算并将结果显示在结果文本框中。