Question

我正在尝试更新标签，以显示它通过队列接收到的数字时正在递减的数字。我可以看到它正在控制台中打印，但是标签没有改变。任何帮助或建议都会有所帮助！

这是我的代码：

import tkinter as tk
import time
import threading
import queue

class GUIApp:
    def __init__(self):
        self.root = tk.Tk()
        self.buttonCountDown = tk.Button(text='Count Down', command=self.countDownAction)
        self.buttonCountDown.pack()
        self.label = tk.Label(text='default')
        self.label.pack()
        self.queue = queue.Queue()
        self.root.mainloop()

    def countDown(self, seconds):
        for i in range(seconds, 0, -1):
            self.queue.put(i)
            time.sleep(1)

    def listenToQueue(self):
        while True:
            try:
                if self.queue.empty() == False:
                    print(self.queue.get(0))
                    self.label['text'] = self.queue.get(0)
                elif self.queue.empty() == True:
                    pass
            except queue.Empty:
                pass

    def countDownAction(self):
        listenThread = threading.Thread(target=self.listenToQueue)
        listenThread.start()
        thread = threading.Thread(target=self.countDown, args=(5,))
        thread.start()
        thread.join()

app = GUIApp()

Answer 1

您需要了解的第一件事是Queue.get()删除项目并将其返回，类似于dict.pop()。因此，当您执行print(self.queue.get(0))时，该项目已从队列中删除。如果要打印和配置它，必须先将其分配给变量：

def listenToQueue(self):
    while True:
        try:
            if self.queue.empty() == False:
                s = self.queue.get(0)
                print (s)
                self.label['text'] = s
            elif self.queue.empty() == True:
                pass
        except queue.Empty:
            pass

接下来，调用thread.join()将等待线程终止。您无需在当前设置中完全调用此方法。

def countDownAction(self):
    listenThread = threading.Thread(target=self.listenToQueue)
    listenThread.start()
    thread = threading.Thread(target=self.countDown, args=(5,))
    thread.start()
    #thread.join() #not required

从队列中获取消息时更新标签

1 个答案: