tkinter .Configure未运行

Question

该代码本质上是一个数学测验，要求用户输入答案。然后，代码将显示答案是对还是错。

代码如下：

from tkinter import *
from tkinter import ttk
import random
import time

class TimesTable:

    def __init__(self, parent):
        """ Sets up the GUI. 
        """
        self.points = 0

        self.problem_label = ttk.Label(parent, text = "Question:") #empty for now
        self.problem_label.grid(row = 0, column=0, sticky = W, padx = 10, pady = 10)

        self.answer_entry = ttk.Entry(parent, width = 7)

        self.check_btn = ttk.Button(parent, text = "Check Answer", command = self.Check)

        self.next_btn = ttk.Button(parent, text = "Start", command = self.Next)
        self.next_btn.grid(row = 0, column = 1, sticky = W, padx = 10, pady = 10)

        self.feedback = ttk.Label(parent, text = "Click 'Start' to begin!")
        self.feedback.grid(row = 1, column = 0, sticky = W, padx = 10, pady = 10)


    def Next(self):
        time.sleep(0.2)
        ***self.feedback.configure(text = "")*** #Fix this (taking it out makes the .configure in Check work)
        number1 = random.randrange(2,10)
        number2 = random.randrange(2,10)
        operation = ["*", "+", "-"]
        operation_ran = operation[(random.randrange((len(operation))))]
        display_question = "Question: {} {} {} = ".format(number1, operation_ran, number2)
        self.ans = eval("{} {} {} ".format(number1, operation_ran, number2))
        self.problem_label.configure(text = display_question)
        self.check_btn.grid(row = 1, column = 1, sticky = W, padx = 10, pady = 10)
        self.answer_entry.grid(row = 0, column = 1, sticky = W, padx = 10, pady = 10)
        self.next_btn.grid_remove()

    def Check(self):
        try:
            if int(self.answer_entry.get()) == int(self.ans):
                ***self.feedback.configure(text = "Correct!")*** #Why does this not work? in def Next, it is configured to nothing but shouln't it still sleep for 0.2s before configuring to nothing via the calling of method def Next???
                self.points += 1
                self.answer_entry.delete(0,END)
                self.answer_entry.focus()
                print(self.points) #Just to check point system works
                self.Next()
            else:
                ***self.feedback.configure(text = "Wrong. The answer is {}".format(self.ans))***
                if self.points > 0:
                    self.points -= 1
                self.answer_entry.delete(0,END)
                self.answer_entry.focus()
                print(self.points)
                self.Next()

        except ValueError:
            self.feedback.configure(text = "Please enter a valid number")
            self.answer_entry.delete(0,END)
            self.answer_entry.focus()

#main routine
if __name__ == "__main__":
    root = Tk()
    root.title("Math Quiz")
    tester = TimesTable(root)
    root.mainloop()

Answer 1

这两个配置都运行正常，但你看不到“正确”的文本，因为它正在等待，你需要更新你的屏幕，然后才能让它等待看到变化。

为此，您可以使用update_idletasks方法。

此外，您还可以使用after方法来代替睡眠。对于这段特定的代码，这并不重要，但至少可以避免另一次导入(time模块)。

def Next(self):
    root.update_idletasks()
    root.after(200)
    self.feedback.configure(text = "")