Java语言程序设计基础篇_编程练习题*15.23 (自动改变大小的停止标识)

*15.23 (自动改变大小的停止标识)

重写编程练习题14.15, 当窗体改变大小的时候，停止标识的宽度和髙度自动改变大小

• 习题思路

1. 新建一个Polygon()绘出八边形，new一个Label表示文字STOP
2. 新建一个方法，被调用时重新绘制八边形，并重新设置文字位置
3. 监听Scene，当大小改变时，调用第二步新建的方法

代码示例：编程练习题15_23AutoChangeSizeStop.java

package chapter_15;import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.Pane;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Polygon;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.stage.Stage;public class 编程练习题15_23AutoChangeSizeStop extends Application{Polygon polygon = new Polygon();Label text = new Label("STOP");@Overridepublic void start(Stage primaryStage) throws Exception {Pane pane = new StackPane();pane.getChildren().add(polygon);polygon.setFill(Color.RED);//polygon.setStroke(Color.BLACK);ObservableList<Double> list = polygon.getPoints();final double WIDTH = 200, HEIGHT = 200;double centerX = WIDTH / 2, centerY = HEIGHT / 2;double radius = Math.min(WIDTH, HEIGHT)*0.4;for(int i = 0;i < 8;i++) {list.add(centerX + radius * Math.cos(34.95+2 * i* Math.PI / 8));list.add(centerY -radius * Math.sin(34.95+2 * i * Math.PI / 8));}text.setTextFill(Color.WHITE);text.setFont(Font.font("Times New Roman", FontWeight.BOLD, 30));pane.getChildren().add(text);Scene scene = new Scene(pane, WIDTH, HEIGHT);scene.widthProperty().addListener((observable, oldValue, newValue) -> resizeComponents(newValue.doubleValue(), scene.getHeight()));scene.heightProperty().addListener((observable, oldValue, newValue) -> resizeComponents(scene.getWidth(), newValue.doubleValue()));primaryStage.setTitle("编程练习题15_23AutoChangeSizeStop");primaryStage.setScene(scene);primaryStage.show();}public static void main(String[] args) {Application.launch(args);}private void resizeComponents(double width, double height) {double centerX = width / 2;double centerY = height / 2;double radius = Math.min(width, height) * 0.4;// Update polygon pointsObservableList<Double> points = polygon.getPoints();points.clear();for (int i = 0; i < 8; i++) {points.add(centerX + radius * Math.cos(34.95+2 * i* Math.PI / 8));points.add(centerY -radius * Math.sin(34.95+2 * i * Math.PI / 8));}// Update label propertiesdouble fontSize = radius / 3; // Adjust font size based on radiustext.setLayoutX(centerX - text.getLayoutBounds().getWidth() / 2);text.setLayoutY(centerY + text.getLayoutBounds().getHeight() / 2);text.setFont(Font.font("Times New Roman", FontWeight.BOLD, fontSize));}
}

• 结果展示