forward需要1个参数（给定0个）

Question

from turtle import *
from Tkinter import *

class TurtleApp:
    def left(self):
            self.turtle.right(90)
    def forward(self):
            self.turtle.forward(self.step)
    def right(self):
            self.turtle.right(90)
    def backward(self):
            self.turtle.backward(self.step)


    def __init__(self):
            self.main = Tk()
            self.main.title('TurtleApp')
            self.step = 10
            self.turtle = Turtle()
            self.window = Screen()
            self.window.setup(500,500)
            self.turtle.speed(self.step)
            topFrame = Frame(self.main)
            topFrame.pack(side='top')
            topLabel = Label(topFrame, text='Turtle Controls')
            topLabel.pack()
            self.createDirectionPad()
            self.createStepEntry()

    def createDirectionPad(self):
            leftFrame = Frame(self.main)
            leftFrame.pack(side='left')
            leftButton = Button(leftFrame, text='Left',command=left)
            forwardButton = Button(leftFrame, text='Forward',command=forward)
            rightButton = Button(leftFrame, text='Right',command=right)
            backwardButton = Button(leftFrame, text='Backward',command=backward)
            leftButton.grid(row=1,column=0)
            forwardButton.grid(row=0,column=1)
            rightButton.grid(row=1,column=2)
            backwardButton.grid(row=2,column=1)

    def createStepEntry(self):
            rightFrame = Frame(self.main)
            rightFrame.pack(side='right')
            stepLabel = Label(rightFrame,text='Enter step size')
            stepLabel.pack(side='top')
            stepEntry = Entry(rightFrame)
            stepEntry.pack()
            stepButton = Button(rightFrame,text='Change step size')
            stepButton.pack(side='bottom')


root = TurtleApp()

root.main.mainloop()

当我运行这个程序，然后单击“Forward”按钮时，我得到一个类型错误，表示给定了0个参数。除了自我（已经给了？）我不知道该怎么说。是我在这里遗漏了什么东西，还是计划太差，以至于无法移动海龟？你知道吗

Answer 1

您需要引用在TurtleApp类中定义的forward()方法，而不是在turtle模块中定义的turtle.forward()函数。调用后者是因为from turtle import *将forward()放入全局范围，因此调用了错误的forward()。你知道吗

将createDirectionPad()中的代码更改为在引用类的方法时使用self：

    leftButton = Button(leftFrame, text='Left',command=self.left)
    forwardButton = Button(leftFrame, text='Forward',command=self.forward)
    rightButton = Button(leftFrame, text='Right',command=self.right)
    backwardButton = Button(leftFrame, text='Backward',command=self.backward)