如何在新的 Tkinter 窗口打开时运行可取消的函数

Question

在 tkinter 中，我想创建以下内容：

当按下按钮 foo 时，函数 foo 立即开始运行。将弹出一个带有“取消”按钮的新窗口，让用户中途终止进程（因为我的实际进程可能需要长达 30 分钟）。如果 foo 运行完成，则窗口会自行关闭并通知用户该过程已完成。

这是演示我的玩具问题的代码：

from tkinter import ttk, messagebox, Toplevel, Tk
import time
import multiprocessing

def foo():
    for i in range(100):
        print(i)
        time.sleep(0.1)

class TerminatedProcess(Exception):
    def __init__(self, str = "Process was terminated"):
        self.error_str = str

class ProcessWindow(Toplevel):
    def __init__(self, parent, process):
        Toplevel.__init__(self, parent)
        self.parent = parent
        self. process = process

        terminate_button = ttk.Button(self, text="Cancel", command=self.cancel)
        terminate_button.grid(row=0, column=0)

        self.grab_set() # so you can't push submit multiple times

    def cancel(self):
        self.process.terminate()
        self.destroy()
        raise TerminatedProcess

    def launch(self):
        self.process.start()
        self.process.join()
        self.destroy()

class MainApplication(ttk.Frame):
    def __init__(self, parent, *args, **kwargs):
        ttk.Frame.__init__(self, parent, *args, **kwargs)
        self.parent = parent

        self.button = ttk.Button(self, text = "foo", command = self.callback)
        self.button.grid(row = 0, column = 0)

    def callback(self):
        try:
            proc = multiprocessing.Process(target=foo)
            process_window = ProcessWindow(self, proc)
            process_window.launch()
        except TerminatedProcess as e: # raised if foo is cancelled in other window
            messagebox.showinfo(title="Cancelled", message=e.error_str)
        else:
            messagebox.showinfo(message="sucessful run", title="Finished")

def main():
    root = Tk()
    my_app = MainApplication(root, padding=(4))
    my_app.grid(column=0, row=0)
    root.mainloop()

if __name__ == '__main__':
    main()

使用此代码，当按下按钮 foo 时，确实会创建 process_window，因为函数 foo 运行，并且我得到一个“运行成功”对话框，但该窗口从未弹出！这是一个问题，因为用户需要有终止 foo 的选项。有趣的是，如果我删除 process_window.launch()，我仍然会收到“运行成功”消息（如预期的那样），但 process_window 会显示出来。

我尝试将启动命令放在初始化中，但这也导致窗口不显示。

我也尝试过在窗口声明之外启动进程，如下：

proc.start()
process_window = ProcessWindow(self, proc)
proc.join()

窗口仍然无法显示，但进程已运行。

我的问题是，我需要如何安排这些部分来生成 ProcessWindow 并在 ProcessWindow 打开时自动启动进程？

更新（解决方法）：我知道我可以在 ProcessWindow 中创建一个启动按钮来运行该功能（然后在按下一次后禁用该按钮），但我仍然想知道如何实现原始问题中描述的内容。

Answer 1

也许你正在寻找这样的东西：

from tkinter import ttk, messagebox, Toplevel, Tk
import time
import multiprocessing

def foo():
    for i in range(100):
        print(i)
        time.sleep(0.1)

class ProcessWindow(Toplevel):
    def __init__(self, parent, process):
        Toplevel.__init__(self, parent)
        self.parent = parent
        self.process = process

        terminate_button = ttk.Button(self, text="Cancel", command=self.cancel)
        terminate_button.grid(row=0, column=0)

        self.grab_set() # so you can't push submit multiple times

    def cancel(self):
        self.process.terminate()
        self.destroy()
        messagebox.showinfo(title="Cancelled", message='Process was terminated')

    def launch(self):
        self.process.start()
        self.after(10, self.isAlive)            # Starting the loop to check when the process is going to end

    def isAlive(self):
        if self.process.is_alive():                     # Process still running
            self.after(100, self.isAlive)               # Going again...
        elif self:
            # Process finished
            messagebox.showinfo(message="sucessful run", title="Finished")
            self.destroy()

class MainApplication(ttk.Frame):
    def __init__(self, parent, *args, **kwargs):
        ttk.Frame.__init__(self, parent, *args, **kwargs)
        self.parent = parent

        self.button = ttk.Button(self, text = "foo", command = self.callback)
        self.button.grid(row = 0, column = 0)

    def callback(self):
        proc = multiprocessing.Process(target=foo)
        process_window = ProcessWindow(self, proc)
        process_window.launch()

def main():
    root = Tk()
    my_app = MainApplication(root, padding=(4))
    my_app.grid(column=0, row=0)
    root.mainloop()

if __name__ == '__main__':
    main()