JavaFX 指定路徑的球

package FXExample;

import javafx.animation.PathTransition;
import javafx.animation.PathTransitionBuilder;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Point2D;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.SceneBuilder;
import javafx.scene.input.MouseEvent;
import javafx.scene.paint.Color;
import javafx.scene.paint.CycleMethod;
import javafx.scene.paint.RadialGradient;
import javafx.scene.paint.Stop;
import javafx.scene.shape.Circle;
import javafx.scene.shape.CircleBuilder;
import javafx.scene.shape.LineTo;
import javafx.scene.shape.MoveTo;
import javafx.scene.shape.Path;
import javafx.stage.Stage;
import javafx.util.Duration;


public class WorkingWithTheSceneGraph extends Application{

	Path onePath = new Path();
	Point2D anchorPt;//anchor:錨
	public static void main(String[] args) {
		launch(args);
	}

	@Override
	public void start(Stage primaryStage) throws Exception {
		primaryStage.setTitle("Chapter 2-3 Working with the Scene Graph");
		final Group root = new Group();
		root.getChildren().add(onePath);
		
		final Scene scene = SceneBuilder.create()
				.root(root)
				.width(300)
				.height(300)
				.fill(Color.PINK)
				.build();
		RadialGradient gradient1 = new RadialGradient(0,.1,100,100,20,false,CycleMethod.NO_CYCLE,
				new Stop(0,Color.RED),new Stop(1,Color.BLACK));
		
		//sphere:n. 範圍；球體
		final Circle sphere = CircleBuilder.create()
				.centerX(100).centerY(100).radius(20).fill(gradient1).build();
		root.getChildren().add(sphere);
		
		// animate sphere by following the path.通過下面的路徑動畫
		final PathTransition pathTransition = PathTransitionBuilder.create()
				.duration(Duration.millis(4000))//持續時間
				.cycleCount(1)//循環週期
				.node(sphere)//形狀
				.path(onePath)//路徑
				.orientation(PathTransition.OrientationType.ORTHOGONAL_TO_TANGENT)//方向
				.build();
		
		// once finished clear path.結束後清除路徑
		pathTransition.onFinishedProperty().set(new EventHandler<ActionEvent>(){

			@Override
			public void handle(ActionEvent event) {
				onePath.getElements().clear();
				
			}});
		
		// starting initial path:初始路徑
		scene.onMousePressedProperty().set(new EventHandler<MouseEvent>(){

			@Override
			public void handle(MouseEvent event) {
				onePath.getElements().clear();
				anchorPt = new Point2D(event.getX(),event.getY());
				onePath.setStroke(Color.BLACK);
				onePath.setStrokeWidth(3);
				onePath.getElements().add(new MoveTo(anchorPt.getX(),anchorPt.getY()));
				
			}});
		// dragging creates lineTos added to the path拖動創建lineTos添加到路徑
		scene.onMouseDraggedProperty().set(new EventHandler<MouseEvent>(){

			@Override
			public void handle(MouseEvent event) {
				onePath.getElements().add(new LineTo(event.getX(),event.getY()));
			}});
		scene.onMouseReleasedProperty().set(new EventHandler<MouseEvent>(){

			@Override
			public void handle(MouseEvent event) {
				onePath.setStrokeWidth(10);
				if(onePath.getElements().size() > 1){
					pathTransition.stop();
					pathTransition.playFromStart();
				}
				
			}});
		
		primaryStage.setScene(scene);
        primaryStage.show();
	}

}