Snake collision不工作- Java处理

Question

我正在和学生们一起制作一个蛇游戏，我们即将完成，但我们添加的最后一件事不起作用:如果蛇与自己相撞，它不会结束游戏！检查背后的逻辑是正确的，它似乎在较低的帧率下更可靠，尽管它仍然不是在任何时候都能正确工作。

用于检测冲突的代码位于draw()中，并编写为：

    System.out.println("headX: " + x.get(x.size()-1) + "\theadY: " +y.get(y.size()-1));
    for (int i=0; i < x.size()-1; i++) {
      System.out.println("i: " + i + "\tx: " + x.get(i) + "\ty: " + y.get(i));
      if ((x.get(x.size()-1) == x.get(i)) && (y.get(y.size()-1) == y.get(i))) {
        println("=======================================");
        alive = false;
        textSize(90);
        text("YOU LOSE", 300, 400);
      }
    }

这包括我为检查而添加的一些print语句，并且它确实具有if语句中的条件，而无需执行if语句中的代码。

蛇被保存在数组列表中，作为一系列x和y坐标，并从每个坐标绘制一个矩形。这个for循环应该检查除头部之外的每个蛇片的坐标，并将其与头部进行比较。即使它是真的，代码也不会总是执行。

下面是在Processing IDE中编写的完整代码

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Random;
boolean moveRight = true;
boolean moveLeft = false;
boolean moveUp = false;
boolean moveDown = false;
boolean alive = true;

Random food = new Random();
int foodX = food.nextInt(100)*10;
int foodY = food.nextInt(100)*10;

ArrayList<Integer> x = new ArrayList<Integer>(Arrays.asList(0, 10, 20, 30, 40, 50, 60, 70, 80, 80, 70, 60, 50, 40, 30, 20, 20));
ArrayList<Integer> y = new ArrayList<Integer>(Arrays.asList(0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 10, 10, 10, 10, 10, 20));
void setup() {
  size(1000, 1000);
  frameRate(60);
}
  void draw() {
    if (alive) {
      background(242, 195, 53);
      if (moveRight) {
        int headX = x.get(x.size()-1)+10;
        int headY = y.get(y.size()-1);
        x.add(headX);
        y.add(headY);
        //if you eat food, stuff below is false
        if (headX != foodX || headY != foodY) {
          x.remove(0);
          y.remove(0);
        } else {
          updateFood();
        }
      }
      if (moveLeft) {
        int headX = x.get(x.size()-1)-10;
        int headY = y.get(y.size()-1);
        x.add(headX);
        y.add(headY);
        if (headX != foodX || headY != foodY) {
          x.remove(0);
          y.remove(0);
        } else {
          updateFood();
        }
      }
      if (moveUp) {
        int headX = x.get(x.size()-1);
        int headY = y.get(y.size()-1)-10;
        x.add(headX);
        y.add(headY);
        if (headX != foodX || headY != foodY) {
          x.remove(0);
          y.remove(0);
        } else {
          updateFood();
        }
      }
      if (moveDown) {
        int headX = x.get(x.size()-1);
        int headY = y.get(y.size()-1)+10;
        x.add(headX);
        y.add(headY);
        if (headX != foodX || headY != foodY) {
          x.remove(0);
          y.remove(0);
        } else {
          updateFood();
        }
      }

      drawFood();
      fill(25, 62, 125);

      for (int i=0; i < x.size(); i++) {
        rect(x.get(i), y.get(i), 10, 10);
      }
      if (x.get(x.size() -1) >1000 || y.get(y.size()  -1) > 1000 || x.get(x.size() -1) < 0 || y.get(y.size() -1) < 0) {
        textSize(90);
        text("YOU LOSE", 300, 400);
        fill(255, 255, 255);

        alive = false;
      }
      System.out.println("headX: " + x.get(x.size()-1) + "\theadY: " +y.get(y.size()-1));
      for (int i=0; i < x.size()-1; i++) {
        System.out.println("i: " + i + "\tx: " + x.get(i) + "\ty: " + y.get(i));
        if ((x.get(x.size()-1) == x.get(i)) && (y.get(y.size()-1) == y.get(i))) {
          println("=======================================");
          alive = false;
          textSize(90);
          text("YOU LOSE", 300, 400);
        }
      }
    }
  } 



  void keyPressed()
  {
    if (key == 'd') {
      if (!moveLeft) {

        moveRight = true;
        moveLeft = false;
        moveUp = false;
        moveDown = false;
      }
    }
    if (key == 'a') {
      if (!moveRight) {
        moveLeft = true;
        moveUp = false;
        moveRight = false;
        moveDown = false;
      }
    }

    if (key == 'w') {
      if (!moveDown) {
        moveUp = true;
        moveLeft = false;
        moveDown = false;
        moveRight = false;
      }
    }
    if (key == 's') {
      if (!moveUp)
        moveUp = false;
      moveLeft = false;
      moveDown = true;
      moveRight = false;
    }
  }
  void drawFood() {
    fill(255, 12, 12);
    rect(foodX, foodY, 10, 10);
  }
  void updateFood() {
    foodX = food.nextInt(100)*10;
    foodY = food.nextInt(100)*10;
  }

编辑:整数不能可靠地使用==，它们必须使用.equals。看看这个问题：Java: Integer equals vs. ==

Answer 1

整数并不总是与==一起使用，而是必须使用.equals。改变

if(x.get(x.size()-1) == x.get(i)) && (y.get(y.size()-1) == y.get(i))

至

if(x.get(x.size()-1).equals(x.get(i))) && (y.get(y.size()-1.equals(y.get(i)))

解决了问题