我正在用python编写一个蛇游戏。但如果我们快速按下两个按钮，它会在一个滴答声中发出两个命令。我能做些什么来防止它？

在我的蛇游戏中，我遇到了以下问题：如果蛇向右移动，玩家连续快速地向上和向左按键，蛇向左转弯，越过身体，游戏结束，将其视为碰撞。如何防止游戏在蛇移动之前执行两个改变方向的命令

我检查按下哪个键的代码如下：

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT and left == False:
                right = True
                up = False
                down = False
            elif event.key == pygame.K_LEFT and right == False:
                left = True
                up = False
                down = False
            elif event.key == pygame.K_DOWN and up == False:
                down = True
                right = False
                left = False
            elif event.key == pygame.K_UP and down == False:
                up = True
                right = False
                left = False

可以找到项目的完整代码

---

要运行代码，您需要通过pip安装pygame软件包。

如果我理解正确，您遇到了一个问题，即当您的蛇向右移动时，您按下向上键，然后快速连续按下向左键，蛇头向左转动，从而导致与自己的身体发生碰撞

这看起来像是你的蛇的运动独立于按键，这会导致在一次移动中按下两个键的可能性，并且因为唯一的条件是蛇没有向右移动，这在你按下向上键后实际上是正确的，它会导致这种行为

---

防止这种情况发生的一种快速方法是设置一些变量，例如从上次按下时开始移动的

，每次蛇移动时，您都会指定
True
，每次按下键时，您都会指定
False
。然后，在检查按下了哪个键时，检查
True
值。
问题是，检查键的频率比蛇移动的频率高。例如，在蛇向上移动之前，您可以按向上和向左，这将导致只向左移动。要解决此问题，您需要一个标志，指示蛇已移动，以便您知道何时检查是否再次按下按键：

moved = True

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        if event.type == pygame.KEYDOWN:
            if(moved):
                if event.key == pygame.K_RIGHT and left == False:
                    right = True
                    up = False
                    down = False
                    moved = False
                elif event.key == pygame.K_LEFT and right == False:
                    left = True
                    up = False
                    down = False
                    moved = False
                elif event.key == pygame.K_DOWN and up == False:
                    down = True
                    right = False
                    left = False
                    moved = False
                elif event.key == pygame.K_UP and down == False:
                    up = True
                    right = False
                    left = False
                    moved = False

    if up:
        next = (snakes_block[0][0], snakes_block[0][1] - 1)
        imghadd = pygame.transform.rotate(imghad, 180)
        moved = True
    elif down:
        next = (snakes_block[0][0], snakes_block[0][1] + 1)
        imghadd = pygame.transform.rotate(imghad, 360)
        moved = True
    elif left:
        next = (snakes_block[0][0] - 1, snakes_block[0][1])
        imghadd = pygame.transform.rotate(imghad, 270)
        moved = True
    elif right:
        next = (snakes_block[0][0] + 1, snakes_block[0][1])
        imghadd = pygame.transform.rotate(imghad, 90)
        moved = True

moved变量用于检查自按下按键后蛇是否已移动，程序仅在移动后检测按键，这样您就无法使蛇朝其无法移动的方向移动。
问题是所有事件都保留在列表中，您会减慢代码速度，以便系统有时间放置两个（或更多）按键
KEYDOWN
此列表中的事件，然后运行
for event
循环，检查此列表中的所有
KEYDOWN

正如@VaclavPelc提到的，若您已经改变了方向并跳过了其他键，那个么您可以使用变量来控制

这样，当您按下多个键时，它将只使用第一个正确的键/方向-因此您无法快速更改决策-即，当您向下移动并按下
左
和
右
时，它将使用
左
，因为这是第一个正确的方向

while True:

    changed_direction = False

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.KEYDOWN:
            if not changed_direction:
                if event.key == pygame.K_RIGHT and left == False:
                    right = True
                    up = False
                    down = False
                    changed_direction = True
                elif event.key == pygame.K_LEFT and right == False:
                    left = True
                    up = False
                    down = False
                    changed_direction = True
                elif event.key == pygame.K_DOWN and up == False:
                    down = True
                    right = False
                    left = False
                    changed_direction = True
                elif event.key == pygame.K_UP and down == False:
                    up = True
                    right = False
                    left = False
                    changed_direction = True

while True:

    previous_left = left
    previous_right = right
    previous_up = up
    previous_down = down
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT and previous_left == False:
                right = True
                up = False
                down = False
            elif event.key == pygame.K_LEFT and previous_right == False:
                left = True
                up = False
                down = False
            elif event.key == pygame.K_DOWN and previous_up == False:
                down = True
                right = False
                left = False
            elif event.key == pygame.K_UP and previous_down == False:
                up = True
                right = False
                left = False


另一种方法是将上一个方向保留在不同的变量中，并在检查上一个方向时使用这些变量

while True:

    changed_direction = False

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.KEYDOWN:
            if not changed_direction:
                if event.key == pygame.K_RIGHT and left == False:
                    right = True
                    up = False
                    down = False
                    changed_direction = True
                elif event.key == pygame.K_LEFT and right == False:
                    left = True
                    up = False
                    down = False
                    changed_direction = True
                elif event.key == pygame.K_DOWN and up == False:
                    down = True
                    right = False
                    left = False
                    changed_direction = True
                elif event.key == pygame.K_UP and down == False:
                    up = True
                    right = False
                    left = False
                    changed_direction = True

while True:

    previous_left = left
    previous_right = right
    previous_up = up
    previous_down = down
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT and previous_left == False:
                right = True
                up = False
                down = False
            elif event.key == pygame.K_LEFT and previous_right == False:
                left = True
                up = False
                down = False
            elif event.key == pygame.K_DOWN and previous_up == False:
                down = True
                right = False
                left = False
            elif event.key == pygame.K_UP and previous_down == False:
                up = True
                right = False
                left = False

这样，当您按下多个键时，它将使用最后一个正确的键/方向-这样您可以快速更改决策-即，当您向下移动并按下
左
和
右
时，它将使用
右
，因为这是最后一个正确的方向

while True:

    changed_direction = False

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.KEYDOWN:
            if not changed_direction:
                if event.key == pygame.K_RIGHT and left == False:
                    right = True
                    up = False
                    down = False
                    changed_direction = True
                elif event.key == pygame.K_LEFT and right == False:
                    left = True
                    up = False
                    down = False
                    changed_direction = True
                elif event.key == pygame.K_DOWN and up == False:
                    down = True
                    right = False
                    left = False
                    changed_direction = True
                elif event.key == pygame.K_UP and down == False:
                    up = True
                    right = False
                    left = False
                    changed_direction = True

while True:

    previous_left = left
    previous_right = right
    previous_up = up
    previous_down = down
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT and previous_left == False:
                right = True
                up = False
                down = False
            elif event.key == pygame.K_LEFT and previous_right == False:
                left = True
                up = False
                down = False
            elif event.key == pygame.K_DOWN and previous_up == False:
                down = True
                right = False
                left = False
            elif event.key == pygame.K_UP and previous_down == False:
                up = True
                right = False
                left = False

您应该使用
print（）
来调试它，并查看当您按下左键时
right
是否为false。顺便说一句：相反
delay（500）
您可以使用
mainClock。勾选（2）
以获得相同的效果。无需使用
mainClock。如果您将其延迟到一秒内仅显示两帧，则勾选（40）
。您正在检查
False
。您不应该检查
是否为True
。如果我以前使用的键L是
UP
，那么
UP
应该是
True
。所以如果我按下
键
，那么，我是否应该检查previous是否为
UP
？然后改变方向？