Python tkinter mainloop 在关闭窗口时不会退出 [英] Python tkinter mainloop not quitting on closing the window

问题描述

我是编程和 Python 的新手，正在制作一个用于练习的计算器应用程序.我在 Python 2.7 中使用 Tkinter.该应用程序具有您所期望的各种按钮，以及用于显示数字/结果的条目和标签小部件.

I'm new to programming and Python, and am making a calculator app to practise. I'm using Tkinter with Python 2.7. The app has various buttons as you'd expect, and Entry and Label widgets for showing the numbers/result.

我认为我的程序确实启动了主循环，但关闭窗口并不会停止主循环.由于在我添加 after 循环之前它确实正常工作，我认为 after 是问题所在.我也在使用 wait_variable.

I think my program does start mainloop, but closing the window doesn't stop mainloop. Since it did work as normal before I added an after loop, I assume the after is the problem. I'm also using wait_variable.

如果您能查看我的代码并提供一些建议，我将不胜感激！我已经包括了主要的东西；创建小部件和处理用户输入/结果输出的代码位于不同的文件(按钮、显示、输入)中，但希望没有这些文件也能理解.

I'd be very grateful if you could have a look at my code and give some advice! I've included the main stuff; the code to create the widgets and deal with user input/results output are in different files (Buttons, Displays, Inputs) but hopefully it's understandable without those.

import Tkinter as tk
# These contain the other bits of code
import Buttons as bt
import Displays as ds
import Inputs as ip


class MainWindow(tk.Frame):
    def __init__(self, parent):
        tk.Frame.__init__(self, parent)
        self.parent = parent
        self.parent.title("Calculator")

        # Making frames to fill with widgets
        self.displays_frame = tk.Frame(parent)
        self.displays_frame.grid(padx=10, pady=10)
        self.buttons_frame = tk.Frame(parent)
        self.buttons_frame.grid()
        # Initialising the widgets and user input functions
        self.display = ds.Displays(self.displays_frame)
        self.button = bt.Button(self.buttons_frame)
        self.input = ip.Inputs()

    def take_inputs(self, parent):
        self.parent = parent

        # This waits for a button to be pressed
        self.wait_variable(self.button.button_pressed)
        # On a button press, its value is inserted into display Entry box/result is put in Label
        # Both self.button.button_pressed above and self.display.r below are StringVars
        self.input.process_input(self.button.button_pressed, self.display.entry_box, self.display.r)
        # Using after here so it keeps waiting for button presses to be recorded
        self.after(100, self.take_inputs, self.parent)

def main():
    root = tk.Tk()
    app = MainWindow(root)
    # Here the wait_variable and after functions are called
    app.take_inputs(root)
    # The below string is printed after the first button has been pressed
    print "main, now starting mainloop" 
    root.mainloop()
    # "finished" is never printed
    print "finished"

if __name__ == '__main__':
    main()

因为我想我已经制作了自己的事件处理程序而不是使用 mainloop，我确实尝试将 self.parent.protocol("WM_DELETE_WINDOW", self.end(parent)) 添加到 take_inputs方法，因此我可以退出所有内容而无需运行主循环.self.end 函数有一个方法，我添加到 MainWindow 类中，该方法打印现在关闭"，然后退出或销毁程序.

As I suppose I've made my own event handler instead of using mainloop, I did try adding self.parent.protocol("WM_DELETE_WINDOW", self.end(parent)) to the take_inputs method, so I could quit everything without needing to run mainloop. The self.end function there was a method I added to MainWindow class that printed "closing now" and then exited or destroyed the program.

然而，我为 protocol 放入的任何函数都会立即运行；WM_DELETE_WINDOW" 没有被正确查找(用foo"替换WM_DELETE_WINDOW"没有给出错误).

However, whatever function I put in there for protocol was run immediately; "WM_DELETE_WINDOW" wasn't being looked up properly (replacing "WM_DELETE_WINDOW" with "foo" didn't give an error).

感谢您的帮助！

推荐答案

我重写了代码，没有使用 wait_variable.我想问题是关闭窗口没有通过 wait_variable 所以代码永远不会回到主循环.

I've rewritten the code without using wait_variable. I suppose the problem was that closing the window did not pass wait_variable so the code never got back to the mainloop.

这是新的 take_inputs 方法.button.button_go 是一个布尔变量，首先定义为 False，但作为按钮绑定到鼠标单击(未显示)的一部分设置为 True.

Here's the new take_inputs method. button.button_go is a Boolean variable first defined as False, but set to True as part of the button binding to the mouse click (not shown).

def take_inputs(self, parent):
    self.parent = parent

    # button.button_go is immediately set to False on updating the display box
    if self.button.button_go == True:
        self.input.process_input(self.button, self.display.entry_box, self.display.r)
        self.button.button_go = False
    self.after(100, self.take_inputs, self.parent)

after() 方法现在按预期与 mainloop 很好地配合.对 wait_variable 感到羞耻.听起来不错，但显然不是很有用.

The after() method now works nicely with mainloop as expected. Shame about wait_variable. It sounded neat but apparently isn't very useful.

我不知道为什么 wm_protocol "WM_DELETE_WINDOW" 定义不起作用！

I don't know why the wm_protocol "WM_DELETE_WINDOW" definition didn't work!

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