在 javaFX 中翻译转换重置位置

Question

我正在尝试将一个圆圈从 (100,200) 移动到 (400,200)，一个循环后圆圈应该开始从 (100,100) 移动到 (200,100) 并继续重复该动作。在第一个循环之后，我使用 circle.setCenterX(100) 和 circle.setCenterY(100) 重置圆的位置。然而，这并没有体现在动画中。圆圈重置为 (400,100) 并继续沿 X 方向向前移动，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, 200, 5, Color.CADETBLUE);
  Circle ref3 = new Circle(100, 100, 5, 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);
  }
}

Answer 1

TranslateTransition 修改 translateX 和 translateY 属性，而不是 centerX 和 centerY 属性。如果您在动画完成时修改 centerX 和 centerY 属性，您还应该将 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 而不是 TranslateTransition 来直接操作动画中的 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);
}

在 javaFX 中翻译转换重置位置

Translate transition reset position in javaFX

java

javafx

transition