用JavaFX显示一个转动的风扇

( 显示一个转动的风扇）编写一个程序显示一个转动的风扇，如图15-33c 所示。Pause、Resume和Reverse 按钮用于暂停、继续和反转风扇的转动。

package javaseniorprograme;

import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.scene.paint.Color;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.shape.Arc;
import javafx.scene.shape.ArcType;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
import javafx.util.Duration;

/**
 * 显示一个转动的风扇
 * @author ASUS
 */
public class Exercise15_28 extends Application{
    @Override
    public void start(Stage stage){
        // 创建一个圆
        Circle c = new Circle(250,135,125,Color.WHITE);
        c.setStroke(Color.BLACK);
        // 创建三个按钮
        Button bt1 = new Button("Pause");
        Button bt2 = new Button("Resume");
        Button bt3 = new Button("Reverse");
        // 创建一个HBox
        HBox hbox = new HBox();
        hbox.setAlignment(Pos.CENTER);
        hbox.setSpacing(20); 
        hbox.getChildren().addAll(bt1,bt2,bt3);
        // 创建四个Arc
        Arc[] a = new Arc[4];
        for(int i = 0; i < 4; i++){
            a[i] = new Arc(250,135,120,120,90*i,30);
            a[i].setStroke(Color.BLACK); 
            a[i].setFill(Color.BLACK); 
            a[i].setType(ArcType.ROUND);
        }
        // 创建时间轴动画,顺时针动画与逆时针动画
        Timeline timeline1 = new Timeline();
        timeline1.setCycleCount(Timeline.INDEFINITE);
        Timeline timeline2 = new Timeline();
        timeline2.setCycleCount(Timeline.INDEFINITE);
        Duration duration = Duration.millis(2000);
        KeyValue[] kv1 = new KeyValue[4];
        KeyFrame[] kf1 = new KeyFrame[4];
        KeyValue[] kv2 = new KeyValue[4];
        KeyFrame[] kf2 = new KeyFrame[4];
        for(int j = 0; j < 4; j++){
            kv1[j] = new KeyValue(a[j].startAngleProperty(), 360+a[j].getStartAngle());
            kf1[j] = new KeyFrame(duration,kv1);
            timeline1.getKeyFrames().add(kf1[j]);
            kv2[j] = new KeyValue(a[j].startAngleProperty(), -360+a[j].getStartAngle());
            kf2[j] = new KeyFrame(duration,kv2);
            timeline2.getKeyFrames().add(kf2[j]);
        }
        bt2.setOnMouseClicked(e->{
            timeline2.pause();
            timeline1.play();
        });
        bt1.setOnMouseClicked(e->{
            timeline1.pause();
            timeline2.pause();
        });
        bt3.setOnMouseClicked(e->{
            timeline1.pause();
            timeline2.play();
        });
        // 创建一个Pane
        Pane pa = new Pane();
        pa.getChildren().addAll(c,a[0],a[1],a[2],a[3]);
        // 创建一个BorderPane
        BorderPane pane = new BorderPane();
        pane.setCenter(pa); 
        pane.setBottom(hbox); 
        Scene scene = new Scene(pane,500,320);
        stage.setTitle("Exercise16_03");
        stage.setScene(scene);
        stage.show();
    }
    
    /**
     * 
     * @param args
     */
    public static void main(String[] args){
        Application.launch(args); 
    }
}