使用 .goto() 覆盖 python 海龟中先前对象的位置

Question

import turtle

wn = turtle.Screen()
wn.title("Pong")
wn.bgcolor("black")
wn.setup(height= 600, width= 800)
wn.tracer(0)

class Paddle:
    paddle = turtle.Turtle()
    def __init__(self):
        self.paddle.speed(0)
        self.paddle.color("white")
        self.paddle.shape("square")
        self.paddle.shapesize(stretch_wid = 5, stretch_len= 1)
        self.paddle.penup()
    def goto(self,location):
        self.paddle.goto(location,0)   


paddleA = Paddle()
paddleB = Paddle()

paddleA.goto(350)

paddleB.goto(-350)
    
# Ball

ball = turtle.Turtle()
ball.speed(0)
ball.color("white")
ball.shape("square")
ball.penup()
ball.goto(0,0)

# Movement Functions

# Game loop
while True:
    wn.update()

我想让这个显示的是屏幕左右两侧的两个拨片。但是，创建的屏幕中只显示一个桨。这个球拍将是最后一个调用函数 .goto() 的球拍。为什么会这样？对此行为的纠正是什么？

Answer 1

您没有在 class 中创建 唯一可识别的 实例，它只是重复使用已经构建的同一个实例。

class Paddle:
    paddle = turtle.Turtle()
    def __init__(self):
        print( id(self.paddle) )
        self.paddle.speed(0)
        self.paddle.color("white")
        self.paddle.shape("square")
        self.paddle.shapesize(stretch_wid = 5, stretch_len= 1)
        self.paddle.penup()
    def goto(self,location):
        self.paddle.goto(location,0)   
    def color(self,color):
        self.paddle.color(color) 

paddleA = Paddle()
paddleB = Paddle()

paddleA.color('red')
paddleB.color('blue')

paddleA.goto(350)
paddleB.goto(-350)
    
# Ball

ball = turtle.Turtle()
print( id(ball) )
ball.speed(0)
ball.color("white")
ball.shape("square")
ball.penup()
ball.goto(0,0)

3066489872
3066489872
3066490064

将 paddle 构造放入 init 块中：

class Paddle:
    def __init__(self):
        self.paddle = turtle.Turtle()
        print( id(self.paddle) )
        self.paddle.speed(0)
        self.paddle.color("white")
        self.paddle.shape("square")
        self.paddle.shapesize(stretch_wid = 5, stretch_len= 1)
        self.paddle.penup()
    def goto(self,location):
        self.paddle.goto(location,0)   
    def color(self,color):
        self.paddle.color(color)

3065846920
3065847064
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使用 .goto() 覆盖 python 海龟中先前对象的位置

Using .goto() overwrites the location of previous objects in python turtle

python

class

python-turtle