当我尝试添加更多形状时，为什么我的乌龟停止移动？

Question

我正在尝试绘制一个形状，然后使用箭头键在屏幕上移动该形状。我的目标是最终制作一款 2D 游戏，但我不知道如何绘制多个圆圈并使其全部移动。

到目前为止我粘贴了我的代码。画完圆圈后，我尝试画一条线，但似乎不喜欢那样。如果我取出那个 forward 语句，那么我可以再次移动圆圈。

import turtle

def Left():
  move.left(1)
  move.forward(1)

def Right():
  move.right(1)
  move.forward(1)

def Forwards():
  move.forward(1)

def Backwards():
  move.backward(1)

def moving_object(move):
    move.fillcolor('orange')
    move.begin_fill()
    move.circle(20)
    move.forward(10)
    move.end_fill()

screen = turtle.Screen()
screen.setup(600,600)
screen.bgcolor('green')
screen.tracer(0)

move = turtle.Turtle()
move.color('orange')
move.speed(0)
move.width(2)
move.hideturtle()
move.penup()
move.goto(-250, 0)
move.pendown()

screen.listen()
screen.onkeypress(Left, "Left")
screen.onkeypress(Right, "Right")
screen.onkeypress(Forwards, "Up")
screen.onkeypress(Backwards, "Down")

while True :
    move.clear()
    moving_object(move)
    screen.update()

Answer 1

你的海龟代码的整个结构是不正确的。在像海龟这样的事件驱动世界中不应该有 while True:。您的循环逻辑使 moving_object() 内的任何向前运动无限重复，并将您的乌龟推出屏幕。

让我们重建您的程序以展示类似坦克的运动，其中圆圈是坦克，线条是它的枪：

from turtle import Screen, Turtle

DIAMETER = 40

def left():
    turtle.left(15)
    moving_object(turtle)

def right():
    turtle.right(15)
    moving_object(turtle)

def forward():
    turtle.forward(5)
    moving_object(turtle)

def backward():
    turtle.backward(5)
    moving_object(turtle)

def moving_object(move):
    move.clear()

    move.begin_fill()
    move.dot(DIAMETER)  # dot makes position center of circle
    move.end_fill()

    move.forward(DIAMETER/2 + 25)
    move.backward(DIAMETER/2 + 25)  # return so we don't move object

    screen.update()

screen = Screen()
screen.setup(600, 600)
screen.bgcolor('green')
screen.tracer(0)

turtle = Turtle()
turtle.hideturtle()
turtle.color('orange')
turtle.width(5)

screen.onkeypress(left, 'Left')
screen.onkeypress(right, 'Right')
screen.onkeypress(forward, 'Up')
screen.onkeypress(backward, 'Down')
screen.listen()

moving_object(turtle)

screen.update()
screen.mainloop()