Trinket 实现 Turtle Graphics 时出现类型错误

Question

下面的代码在使用 Python 3.10 的 Windows 10 上运行良好。当你点击乌龟时，它的颜色就会改变。但是，当我在基于浏览器的 Trinket 环境中运行代码时，此处：https://trinket.io/python/0da2ab1181，我收到以下错误：

ExternalError: TypeError: Cannot read properties of undefined (reading 'constructor') on line 15 in main.py

当我点击海龟时。

请问我怎样才能正确地工作？我查看了该模块的文档，他们给出了：

Help on function fillcolor in turtle:

turtle.fillcolor = fillcolor(*args)
    Return or set the fillcolor.
    
    Arguments:
    Four input formats are allowed:
      - fillcolor()
        Return the current fillcolor as color specification string,
        possibly in hex-number format (see example).
        May be used as input to another color/pencolor/fillcolor call.
      - fillcolor(colorstring)
        s is a Tk color specification string, such as "red" or "yellow"
      - fillcolor((r, g, b))
        *a tuple* of r, g, and b, which represent, an RGB color,
        and each of r, g, and b are in the range 0..colormode,
        where colormode is either 1.0 or 255
      - fillcolor(r, g, b)
        r, g, and b represent an RGB color, and each of r, g, and b
        are in the range 0..colormode
    
    If turtleshape is a polygon, the interior of that polygon is drawn
    with the newly set fillcolor.
    
    Example:
    >>> fillcolor('violet')
    >>> col = pencolor()
    >>> fillcolor(col)
    >>> fillcolor(0, .5, 0)

程序代码：

class ToggleTurtle(turtle.Turtle):
    def __init__(self):
        super().__init__()
        self.shape("turtle")
        self.color1 = "red"
        self.color2 = "blue"
        self.fillcolor(self.color1)
        self.onclick(self.toggle_color)

    def toggle_color(self, x, y):
        if self.fillcolor() == self.color1:
            self.fillcolor(self.color2)
        else:
            self.fillcolor(self.color1)


tt = ToggleTurtle()

turtle.done()

Answer 1

在这个 trinket.io 海龟库中，像

fillcolor()

是

pencolor()

这样的函数只是 setters，而不是像标准 Python 海龟库中那样同时具有 setter 和 getters。因此，正如@jasonharper 建议的（+1），我们需要明确地跟踪颜色状态：

class ToggleTurtle(turtle.Turtle):
    COLOR_1 = "red"
    COLOR_2 = "blue"

    def __init__(self):
        super().__init__()
        self.shape("turtle")

        self.current_color = self.COLOR_1
        self.fillcolor(self.current_color)

        self.onclick(self.toggle_color)

    def toggle_color(self, x, y):
        if self.current_color == self.COLOR_1:
            self.current_color = self.COLOR_2
        else:
            self.current_color = self.COLOR_1

        self.fillcolor(self.current_color)