当我在课堂上按下 Python Tkinter 中的按钮时如何删除条目

Question

我是初学者。 我可以请你帮忙吗？

如何清除 Python tkinter 中的条目。 我无法清除它。 我尝试了诸如 END 和 'END' 之类的参数，但是当我按下按钮时我无法清除条目

能不能尽快答复谢谢。 我现在在一个项目中工作

这是我的代码：

from tkinter import *
class TkinScreen:
    def main_screen_opening(self):
        self.screen = Tk()
        self.screen.geometry ('500x500')
        self.screen.title ('Rwooggle Account')
        my_heading1 = Label (text = 'Rwooggle.com', bg = 'blue', fg = 'yellow', font = ('Courier', 34, 'italic'), width = '500').pack()
        my_heading = Label (text = 'Login', bg = 'blue', fg = 'black', font = ('Courier', 24, 'bold'), width = '500').pack()

    def variables(self):
        self.username_var = StringVar()
        self.password_var = StringVar()
        self.age_var = IntVar()
        self.city_var = StringVar()

    def labels_entries(self):
        self.username_text = Label (text = 'Username*', font = ('Courier', 18)).pack()
        self.username_entry = Entry (textvariable = self.username_var, width = '30').pack()
        Label (text = "", width = '30').pack()
        
        self.password_text = Label (text = 'Password*', font = ('Courier', 18)).pack()
        self.password_entry = Entry (textvariable = self.password_var, width = '30').pack()
        Label (text = "", width = '30').pack()
        
        self.age_text = Label (text = 'Age', font = ('Courier', 18)).pack()
        self.age_entry = Entry (textvariable = self.age_var, width = '30').pack()
        Label (text = "", width = '30').pack()

        self.city_text = Label (text = 'Country', font = ('Courier', 18)).pack()
        self.city_entry = Entry (textvariable = self.city_var, width = '30').pack()
        Label (text = "", width = '30').pack()

    def button(self):
        log_in_but = Button (text = 'Log In', font = ('Courier', 20), command = self.button_command).pack()

    def button_command(self):
        print ('User Sucessfully Logged In')
        self.user_info = self.username_var.get()
        self.pass_info = self.password_var.get()
        self.pass_print = '*' * (len(self.pass_info))
        self.age_info = self.age_var.get()
        self.city_info = self.city_var.get().capitalize()

        txt_info = f"""\
    Username    :   {self.user_info}
    Password    :   {self.pass_print}
    Age         :   {self.age_info}
    Country     :   {self.city_info}
        """
        print (txt_info)

        self.username_entry.delete(0, 'end')
        self.password_entry.delete(0, 'end')
        self.age_entry.delete(0, 'end')
        self.city_entry.delete(0, 'end')
        

    def function(self):
        self.screen.mainloop()

tkint = TkinScreen ()
tkint.main_screen_opening()
tkint.variables()
tkint.labels_entries()
tkint.button()
tkint.function()

这是错误用户成功登录用户名：FFNNFD 密码：****** 年龄：12 国家：Eggreg

Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Users\Roger Geronimo\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__init__.py", line 1883, in __call__
    return self.func(*args)
  File "C:\Users\Roger Geronimo\Documents\Programming\SublimeText3\baf.py", line 53, in button_command
    self.username_entry.delete(0, 'end')
AttributeError: 'NoneType' object has no attribute 'delete'

我也试过 END 参数

先感谢您

Answer 1

无论您想清除什么条目，请在单击按钮时调用的函数中使用entry.set('')

Answer 2

只是改变

self.username_entry = Entry (textvariable = self.username_var, width = '30').pack()

到

self.username_entry = Entry (textvariable = self.username_var, width = '30')
self.username_entry.pack()

我建议对所有输入框执行此操作，然后像往常一样继续操作，它将解决错误：D

解释：

这是因为self.username_entry = Entry (....).pack()返回None ，即，当您使用self.username_entry.delete(0,'end')您说的是Entry (....).pack().delete(0,'end')就不存在，因为self.username_entry = Entry (....).pack()是 None 他们给出错误，你收到了。

额外提示：

• 我建议在您的小部件上使用master参数，例如Entry(root)或者当您使用更多窗口时，它会造成严重破坏。
• 您可以使用带有 tkinter 的messagebox类的东西，而不是说print ('User Sucessfully Logged In') 。 这是如何

如果您有任何疑问或错误，请告诉我

干杯