翻译javaFX中的过渡重置位置

问题描述

我正在尝试将圆圈从（100,200）移至（400,200），并且在一个周期后，圆圈应开始从（100,100）移至（200,100），并继续重复该运动。在第一个循环之后，我使用circle.setCenterX（100）和circle.setCenterY（100）重置了圆的位置。但是，这没有反映在动画中。圆重置为（400,100），并在X方向上继续前进，而不是重复运动。我是javaFX的新手。任何帮助将不胜感激。

import javafx.animation.*;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.stage.Stage;
import javafx.util.Duration;

public class Test extends Application
{
  public static void main(String[] args)
  {
    launch(args);
  }

  final double lambda = 0.1; // pixel per millisecond
  double posX = 100;
  double posY = 200;
  double time = 0;
  double velocityX = 1*lambda;
  double velocityY = 0*lambda;
  Circle circle = new Circle(posX,posY,20,Color.AQUA);
  Circle ref1 = new Circle(100,200,5,Color.CADETBLUE);
  Circle ref2 = new Circle(400,Color.CADETBLUE);
  Circle ref3 = new Circle(100,100,Color.CADETBLUE);

  @Override
  public void start(Stage stage) throws Exception
  {
    Pane pane = new Pane();
    pane.getChildren().addAll(circle,ref1,ref2,ref3);

    BorderPane root = new BorderPane();
    root.setCenter(pane);
    root.setStyle("-fx-background-color: #29353B");
    double WIDTH = 800;
    double HEIGHT = 600;
    Scene scene = new Scene(root,WIDTH,HEIGHT);
    stage.setScene(scene);
    stage.show();

    move(3000);
  }

  public void move(double dt) // dt in milliseconds
  {
    System.out.println(circle.getCenterX()+","+circle.getCenterY());
    TranslateTransition translateTransition = new TranslateTransition(Duration.millis(dt),circle);
    //translateTransition.setInterpolator(Interpolator.LINEAR);
    translateTransition.setByX(this.velocityX*dt);
    translateTransition.setByY(this.velocityY*dt);
    translateTransition.setCycleCount(1);
    translateTransition.play();
    translateTransition.setOnFinished(actionEvent -> { updatePos(dt); move(2000); });
  }


  public void updatePos(double dt)
  {
    //this.posX += this.velocityX*dt;
    //this.posY += this.velocityY*dt;
    this.posX = 100;
    this.posY = 100;
    circle.setCenterX(this.posX);
    circle.setCenterY(this.posY);
  }
}

解决方法

TranslateTransition修改translateX和translateY属性，而不是centerX和centerY属性。如果在动画完成后修改centerX和centerY属性，则还应将translateX和translateY重置为0，以使圆出现在这些坐标处：>

  public void updatePos(double dt) {
    //this.posX += this.velocityX*dt;
    //this.posY += this.velocityY*dt;
    this.posX = 100;
    this.posY = 100;
    circle.setCenterX(this.posX);
    circle.setCenterY(this.posY);
    circle.setTranslateX(0);
    circle.setTranslateY(0);
  }

或者，您可以使用Timeline代替TranslateTransition来直接操纵动画中的centerX和centerY属性：

public void move(double dt) /* dt in milliseconds */ {
    System.out.println(circle.getCenterX() + "," + circle.getCenterY());
    double targetX = circle.getCenterX() + this.velocityX * dt;
    double targetY = circle.getCenterY() + this.velocityY * dt;
    Timeline timeline = new Timeline(new KeyFrame(Duration.millis(dt),new KeyValue(circle.centerXProperty(),targetX),new KeyValue(circle.centerYProperty(),targetY)));

    timeline.setOnFinished(actionEvent -> {
        updatePos(dt);
        move(2000);
    });
    timeline.play();
}

public void updatePos(double dt) {
    this.posX = 100;
    this.posY = 100;
    circle.setCenterX(this.posX);
    circle.setCenterY(this.posY);
}