目录

题目：*16.2 (选择几何图形)

习题思路

代码示例 

 结果展示

---

题目：*16.2 (选择几何图形)

    编写一个绘制各种几何图形的程序，如图16-36b所示。用户从单选按钮中选择一个几何图形 ，并且使用复选框指定是否被填充

• 习题思路

1. 新建一个Pane，分别创建Circle、Rectangle、Ellipse，设置好参数但不添加到Pane中
2. 新建一个HBox，创建三个RadioButton，和一个CheckBox，把RadioButton绑定在一个组中，当单选按钮被选择时清除Pane上的节点，把对应的图形添加在Pane上，如果复选框被勾选，则填充节点的颜色(填充Pane中的第一个节点即可)
3. 新建一个BorderPane，将Pane设置在在中心，将HBox设置在底部，把Scene的参数设为BorderPane

代码示例： 

编程练习题16_2SelectGeometry.java 

package chapter_16;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.control.RadioButton;
import javafx.scene.control.ToggleGroup;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Ellipse;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class 编程练习题16_2SelectGeometry extends Application{
	@Override
	public void start(Stage primaryStage) throws Exception {
		Pane pane = new Pane();
		pane.setStyle("-fx-border-color: Black");
		double x = 200;
		double y = 100;
		Circle circle = new Circle(x, y,20);
		Rectangle rectangle = new Rectangle(x-50,y-20,100, 40);
		Ellipse ellipse = new Ellipse(x, y, 60, 30);
		circle.setFill(Color.TRANSPARENT);
		circle.setStroke(Color.BLACK);
		rectangle.setFill(Color.TRANSPARENT);
		rectangle.setStroke(Color.BLACK);
		ellipse.setFill(Color.TRANSPARENT);
		ellipse.setStroke(Color.BLACK);
		
		HBox hBox = new HBox(20);
		hBox.setPadding(new Insets(5, 5, 5, 5));
		hBox.setAlignment(Pos.CENTER);
		RadioButton rbCircle = new RadioButton("Circle");
		RadioButton rbRectangle = new RadioButton("Rectangle");
		RadioButton rbEllipse = new RadioButton("Ellipse");
		ToggleGroup group = new ToggleGroup();
		rbCircle.setToggleGroup(group);
		rbRectangle.setToggleGroup(group);
		rbEllipse.setToggleGroup(group);
		CheckBox chkFill = new CheckBox("Fill");
		hBox.getChildren().addAll(rbCircle, rbRectangle, rbEllipse, chkFill);
		
		chkFill.setOnAction(e ->{
			if(chkFill.isSelected()&& (rbCircle.isSelected()||rbRectangle.isSelected()||rbEllipse.isSelected())) {
				pane.getChildren().get(0).setStyle("-fx-fill: black");
			}
			if(!chkFill.isSelected()&& (rbCircle.isSelected()||rbRectangle.isSelected()||rbEllipse.isSelected())) {
				pane.getChildren().get(0).setStyle(null);
			}
		});
		rbCircle.setOnAction(e ->{
			pane.getChildren().clear();
			chkFill.setSelected(false);
			circle.setStyle(null);
			pane.getChildren().add(circle);
		});
		rbRectangle.setOnAction(e ->{
			pane.getChildren().clear();
			chkFill.setSelected(false);
			rectangle.setStyle(null);
			pane.getChildren().add(rectangle);
		});
		
		rbEllipse.setOnAction(e ->{
			pane.getChildren().clear();
			chkFill.setSelected(false);
			ellipse.setStyle(null);
			pane.getChildren().add(ellipse);
		});
		
		BorderPane borderPane = new BorderPane();
		borderPane.setCenter(pane);
		borderPane.setBottom(hBox);
		
		Scene scene = new Scene(borderPane, 400, 226);
		primaryStage.setTitle("编程练习题16_2SelectGeometry");
		primaryStage.setScene(scene);
		primaryStage.show();
	}
	public static void main(String[] args) {
		Application.launch(args);
	}
}

•  结果展示