Question

我有一个简单的类 2Dpoints，有两个字段，x 和 y。我想编写一个代码，以便我可以命令一个点缓慢移动到另一个点，就像它在它们距离的矢量线上移动一样。但我不知道怎么办？我首先想到它应该包含一个 for 循环，以便它知道，它应该移动直到到达另一点类似于 for(int d=0 ; d

import java.lang.Math.*;

public class Punkt { 

    private int x;
    private int y;

    public Punkt(int x, int y) {
        this.x=x;
        this.y=y;
    }

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }

    public void setX(int distance) {
        x = x + distance;
    }

    public void setY(int distance) {
        y = y + distance;
    }

    public void moveAbout(int dx, int dy) {
        x = x + dx;
        y = y + dy;
    }

    /// method for calculating the distance to another point
    public double giveDistance(Punkt otherPoint) {
        return Math.sqrt(
            (otherPoint.getY() - y) * 
            (otherPoint.getY() - y) + 
            (otherPoint.getX() - x) * 
            (otherPoint.getX() - x));
    
    }
}

Answer 1

我已经评论了主要内容：

import static java.lang.Math.*;

/**
 * Immutable structure. Functional way
 */
class Point { 
  public final double x;
  public final double y;

  public Point(double x, double y) {
    this.x = x;
    this.y = y;
  }

  /**
   * Here you are. This is what you want to implement.
   * from.moveTo(0.0, to) => from
   * from.moveTo(1.0, to) => to
   *
   * @param by - from 0.0 to 1.0 (from 0% to 100%)
   * @param target - move toward target by delta
   */
  public Point moveTo(double by, Point target) {
    Point delta = target.sub(this);
    return add(delta.dot(by));
  }

  public Point add(Point point) {
    return new Point(x + point.x, y + point.y);
  }

  public Point sub(Point point) {
    return new Point(x - point.x, y - point.y);
  }

  public Point dot(double v) {
    return new Point(v * x, v * y);
  }

  public double dist(Point point) {
    return sub(point).len();
  }

  public double len() {
    return sqrt(x * x + y * y);
  }

  public String toString() {
    return x + ":" + y;
  }
}

class Main {
  public static void main(String[] args) {
    Point source = new Point(2, 3);
    Point target = new Point(-4, 9);
    // You can utilize the cycle or implement kind of timer to animate something
    for (int t = 0; t <= 100; t++) {
      System.out.println(source.moveTo(0.01 * t, target));
    }
  }
}

https://replit.com/join/sucvdhpqoa-redneckz

Answer 2

@AlexanderAlexandrov 我已经将变量的类型相应地更改为双倍，现在在我的一个类中，我有一个方法 givePoints，它使用 Scanner 询问用户他想要多少点以及坐标是什么，然后它会保存它们变成一个点数组，第一个元素总是（0,0）。另一种方法将一组点作为参数，并按照它们到 point(0,0) 的距离的顺序对它们进行排序。这些方法效果很好。问题在于方法hitThepoints。在这里，我想首先创建点数组，对它们进行排序，然后命令我的机器人击中所有点。 Robot 是 Robot extends circle 类的对象，位置类型为 Point，首先是在 point(0,0)

public void hitThePoints(){

  Point[] poi=sortPoints (givePoints()); //Creates a sorted array of points
  Point short=new Point(poi[1].getX(),poi[1].getY());
  System.out.println(" the nearest point is :");
  System.out.println("("+short.getX()+ ","+short.getY()+")");
         
         for(int i=1; i<poi.length;i++){
              Point source=robot.position;
              Point target=new Point(poi[i].getX(), poi[i].getY());
                 while(source.getX()!=target.getX() && 
                       source.getY()!=target.getY()){
                  
                  robot.bewegeUm((source.moveTo(0.01,target)).getX(), 
                                (source.moveTo(0.01,target)).getY());

                  if(source.getX()!=target.getX() && 
                     source.getY()!=target.getY()){break;}

                  System.out.println(source.getX() +","+ source.getY());
                  
                  }
           }
      }

在 Java 中，我应该如何命令一个 2D 点沿着距离向量线移动到另一个点？

2 个答案: