JavaFX 几何图形计算器的代码

JavaFX 是 Java 平台的一个图形用户界面 (GUI) 库，它允许开发者创建丰富的桌面应用程序。设计一个几何图形计算器，我们可以使用 JavaFX 中的 Shape 类和一些基本的事件处理来实现。以下是一个简单的示例，展示如何创建一个窗口，用户可以选择不同形状并输入边长，然后计算图形的面积：

import javafx.application.Application;
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.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Rectangle;
import javafx.scene.shape.Shape;
import javafx.scene.shape.Square;
import javafx.stage.Stage;

public class GeometryCalculator extends Application {
    private TextField radiusField, lengthField, widthField;
    private Shape shape;
    private double area;

    @Override
    public void start(Stage primaryStage) {
        // 创建窗口
        primaryStage.setTitle("Geometry Calculator");

        // 创建布局
        GridPane grid = new GridPane();
        grid.setHgap(10);
        grid.setVgap(10);

        Label shapeLabel = new Label("Shape:");
        Button circleButton = new Button("Circle");
        Button squareButton = new Button("Square");
        Button rectangleButton = new Button("Rectangle");

        // 设置按钮事件
        circleButton.setOnAction(e -> shape = new Circle(Double.parseDouble(radiusField.getText())));
        squareButton.setOnAction(e -> shape = new Square(Double.parseDouble(lengthField.getText())));
        rectangleButton.setOnAction(e -> shape = new Rectangle(Double.parseDouble(lengthField.getText()), Double.parseDouble(widthField.getText())));

        // 添加字段和按钮
        radiusField = new TextField();
        lengthField = new TextField();
        widthField = new TextField();

        grid.add(shapeLabel, 0, 0);
        grid.add(circleButton, 1, 0);
        grid.add(squareButton, 2, 0);
        grid.add(rectangleButton, 3, 0);
        grid.add(new Label("Radius:"), 1, 1);
        grid.add(radiusField, 2, 1);
        grid.add(new Label("Length:"), 1, 2);
        grid.add(lengthField, 2, 2);
        grid.add(new Label("Width:"), 3, 2);
        grid.add(widthField, 4, 2);

        // 计算区域和显示结果
        Button calculateButton = new Button("Calculate");
        calculateButton.setOnAction(e -> {
            if (shape instanceof Circle) {
                area = Math.PI * Math.pow(Double.parseDouble(radiusField.getText()), 2);
            } else if (shape instanceof Square || shape instanceof Rectangle) {
                area = shape.getBoundsInLocal().getWidth() * shape.getBoundsInLocal().getHeight();
            }
            displayArea();
        });

        grid.add(calculateButton, 5, 2);

        // 清除结果
        Button clearButton = new Button("Clear");
        clearButton.setOnAction(e -> {
            shape = null;
            area = 0;
            radiusField.clear();
            lengthField.clear();
            widthField.clear();
            displayArea();
        });

        grid.add(clearButton, 6, 2);

        Scene scene = new Scene(grid, 400, 300);
        scene.getStylesheets().add(getClass().getResource("styles.css").toExternalForm());
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private void displayArea() {
        if (shape != null) {
            areaLabel.setText("Area: " + area);
        } else {
            areaLabel.setText("Shape not selected.");
        }
    }

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

    private Label areaLabel = new Label("Area: ");
}

这个示例中，我们创建了一个简单的窗口，有选择形状的按钮（圆形、正方形和矩形），以及输入边长的文本框。用户点击“计算”按钮后，根据选择的形状计算并显示面积。同时，我们还有“清除”按钮用于重置输入和结果。