Tkinter GUI启动线程后无响应

Question

我写了一个程序的小例子，它应该在按下start_button后开始运行多批次并行线程。这个过程只能启动一次，在一批线程完成后，它应该检查是否是退出的时候了。

所以例如，它可以像这样：
-批处理1（10个线程）正在运行，在它<代码>stop_button被按下。完成批次1后，程序应该停止而不运行批次2并返回初始状态（再次具有启动此过程的选项）。

但是，在这个过程中，GUI似乎根本无法注册单击或任何东西。它只是看起来冻结了。所以我应该以某种方式将线程从GUI中分离出来，但我不知道具体如何。

import threading
import tkinter as tk
import time
import random


class Blocking():
    def __init__(self):
        self.master = tk.Tk()
        self.master.geometry("400x400")

        self.start_button = tk.Button(self.master, command=self.long_task, text='press me to start', state='normal')
        self.start_button.pack()

        self.stop_button = tk.Button(self.master, command=self.stop_func, text='press me to stop', state='normal')
        self.stop_button.pack()
        self.long_task_was_stopped = False

        self.master.mainloop()

    def one_thread(self, thread_index):
        time.sleep(random.randint(5, 10))

    def long_task(self): # will run many batches of parallel one_thread functions on press of start_button
        self.start_button["state"] = 'disabled'
        # first batch of threads
        threads = []
        for thread_number in range(0,10):
            thread = threading.Thread(target=self.one_thread, args=(thread_number,))
            threads.append(thread)
            thread.start()

        for thread in threads:
            thread.join()

        print("First batch over!")
        # batch over, check if it was stopped
        print("Stop variable value:", self.long_task_was_stopped)
        if self.long_task_was_stopped == True:
            # reset states, quit function
            self.long_task_was_stopped = False
            self.start_button["state"] = 'normal'
            print("Stopped, exiting!")
            return

        # second batch of threads
        threads = []
        for thread_number in range(0,10):
            thread = threading.Thread(target=self.one_thread, args=(thread_number,))
            threads.append(thread)
            thread.start()

        for thread in threads:
            thread.join()

        print("Second batch over!")
        self.long_task_was_stopped = False
        self.start_button["state"] = 'normal'
        print("Done.")
        return

    def stop_func(self):
        print("Trying to stop...")
        self.long_task_was_stopped = True



if __name__ == '__main__':
    block = Blocking()  

编辑：解决方案似乎是在线程启动后继续在Tkinter主窗口上调用update（），并在继续之前检查所有线程，直到所有线程都结束。为此需要使用Lock（）。这是解决办法。

import threading
import tkinter as tk
import time
import random


class Blocking():
    def __init__(self):
        self.master = tk.Tk()
        self.master.geometry("400x400")

        self.start_button = tk.Button(self.master, command=self.long_task, text='press me to start', state='normal')
        self.start_button.pack()

        self.stop_button = tk.Button(self.master, command=self.stop_func, text='press me to stop', state='normal')
        self.stop_button.pack()
        self.long_task_was_stopped = False

        self.LOCK = threading.Lock()
        self.count_of_done_threads = 0
        self.master.mainloop()


    def one_thread(self, thread_index):
        time.sleep(random.randint(5, 10))
        with self.LOCK:
            print("Thread", thread_index, "done.")
            self.count_of_done_threads = self.count_of_done_threads +1

    def long_task(self): # will run many batches of parallel one_thread functions on press of start_button
        self.start_button["state"] = 'disabled'
        self.long_task_was_stopped = False

        # first batch of threads
        threads = []
        for thread_number in range(0,10):
            thread = threading.Thread(target=self.one_thread, args=(thread_number,))
            threads.append(thread)
            thread.start()

        # wait until threads are done
        while 1:
            self.master.update()
            if self.count_of_done_threads == 10: # 10 here is size of batch
                break
        self.count_of_done_threads = 0

        print("First batch over!")
        # batch over, check if it was stopped
        print("Stop variable value:", self.long_task_was_stopped)
        if self.long_task_was_stopped == True:
            # reset states, quit function
            self.long_task_was_stopped = False
            self.start_button["state"] = 'normal'
            print("Stopped, exiting!")
            return

        # second batch of threads
        threads = []
        for thread_number in range(0,10):
            thread = threading.Thread(target=self.one_thread, args=(thread_number,))
            threads.append(thread)
            thread.start()

        # wait until threads are done
        while 1:
            self.master.update()
            if self.count_of_done_threads == 10:
                break
        self.count_of_done_threads = 0

        print("Second batch over!")
        self.long_task_was_stopped = False
        self.start_button["state"] = 'normal'
        print("Done.")
        return

    def stop_func(self):
        print("Trying to stop...")
        self.long_task_was_stopped = True

if __name__ == '__main__':
    block = Blocking()  

Answer 1

您应该使用非阻塞线程。只是线程。start（）正常。在正式文件中：

其他线程可以调用线程的join（）方法。这将阻止调用线程，直到其join（）方法被调用的线程终止。

这意味着只有当您的函数one_thread完成其工作时，您的代码才会运行。

你的代码也许应该是：

import threading
import tkinter as tk
import time
import random


class Blocking():
    def __init__(self):
        self.master = tk.Tk()
        self.master.geometry("400x400")

        self.start_button = tk.Button(self.master, command=self.long_task, text='press me to start', state='normal')
        self.start_button.pack()

        self.stop_button = tk.Button(self.master, command=self.stop_func, text='press me to stop', state='normal')
        self.stop_button.pack()
        self.long_task_was_stopped = False

        self.master.mainloop()

    def one_thread(self, thread_index):
        time.sleep(random.randint(5, 10))

    def long_task(self): # will run many batches of parallel one_thread functions on press of start_button
        self.start_button["state"] = 'disabled'
        # first batch of threads
        threads = []
        for thread_number in range(0,10):
            thread = threading.Thread(target=self.one_thread, args=(thread_number,))
            threads.append(thread)
            thread.start()

        print("First batch over!")
        # batch over, check if it was stopped
        print("Stop variable value:", self.long_task_was_stopped)
        if self.long_task_was_stopped == True:
            # reset states, quit function
            self.long_task_was_stopped = False
            self.start_button["state"] = 'normal'
            print("Stopped, exiting!")
            return

        # second batch of threads
        threads = []
        for thread_number in range(0,10):
            thread = threading.Thread(target=self.one_thread, args=(thread_number,))
            threads.append(thread)
            thread.start()

        print("Second batch over!")
        self.long_task_was_stopped = False
        self.start_button["state"] = 'normal'
        print("Done.")
        return

    def stop_func(self):
        print("Trying to stop...")
        self.long_task_was_stopped = True

if __name__ == '__main__':
    block = Blocking()  

我刮网络图片的最小例子。当你运行这段代码时，它会显示加载...当完成刮擦时，它会显示图片）。

import tkinter
from PIL import ImageTk,Image
import threading,requests
from io import BytesIO

def scrapeImage():
    image = ImageTk.PhotoImage(Image.open(BytesIO(requests.get('https://s2.ax1x.com/2020/02/08/1Wl4mT.md.jpg').content)).resize((200,200))) # crawl my image
    imagePos.image = image # keep reference.
    imagePos['image'] = image


root = tkinter.Tk()
thread = threading.Thread(target=scrapeImage)
thread.start()

imagePos = tkinter.Label(text="loading.....")
imagePos.grid()

root.mainloop()