Python

Question

我正在尝试编写以下代码，但它没有按预期工作

问题：我想首先在 tkinter window 中显示登录按钮，然后弹出一个输入凭据，

但是当我尝试调用命令参数中的方法时，首先出现 "Enter Credentials" 弹出窗口，然后出现 "Login" 按钮，但该按钮没有任何效果。

请建议在这种情况下如何调用登录按钮。

代码如下：

import sys
import tkinter.messagebox as box
from tkinter.filedialog import asksaveasfile
if sys.version_info[0] >= 3:
    import tkinter as tk
else:
    import Tkinter as tk


class App(tk.Frame):

    def __init__(self, master, username, password):
        tk.Frame.__init__(self, master)

        self.dict = {'Asia': ['Japan', 'China', 'Malaysia'],
                     'Europe': ['Germany', 'France', 'Switzerland']}

        self.variable_a = tk.StringVar(self)
        self.variable_b = tk.StringVar(self)

        self.variable_a.trace('w', self.update_options)
        self.variable_b.trace('w', self.fun2)

        self.optionmenu_a = tk.OptionMenu(self, self.variable_a, *self.dict.keys(), command=self.fun)
        self.optionmenu_b = tk.OptionMenu(self, self.variable_b, '')
        export = self.sample(username, password)
        self.button = tk.Button(self,text="Login", command=export)

        self.variable_a.set('Asia')

        self.optionmenu_a.pack()
        self.optionmenu_b.pack()
        self.button.pack()
        self.pack()

    def fun(self,value):
        print(value)

    def fun2(self, *args):
        print(self.variable_b.get())

    def sample(self, username, password):
        box.showinfo('info', 'Enter Credentials')



    def update_options(self, *args):
        countries = self.dict[self.variable_a.get()]
        self.variable_b.set(countries[0])

        menu = self.optionmenu_b['menu']
        menu.delete(0, 'end')

        for country in countries:
            menu.add_command(label=country, command=lambda nation=country: self.variable_b.set(nation))


if __name__ == "__main__":
    root = tk.Tk()
    username = "root"
    password = "admin"
    app = App(root, username, password)
    app.mainloop()

Answer 1

问题出在你如何声明函数 export 来显示弹出窗口，它调用了显示消息框的 sample 方法，这就是你也得到弹出窗口的原因很快。

作为快速修复，直接在命令中用 lambda 替换 export 东西：

self.button = tk.Button(self,
                        text="Login",
                        command=lambda : self.sample(username, password))

Python - tkinter - 如何在命令参数中调用方法

Python - tkinter - How to call a method in command argument

dynamic

tkinter

optionmenu