如何使 Tkinter GUI 线程安全？

Question

我写了一段代码，其中有一个带有画布的简单 GUI。 在这个画布上我画了一个 Matplot。 Matplot 每秒更新一次来自 SQ Lite DB 的数据，我填充了一些虚假的传感器信息（目前仅用于测试）。

我的问题是画布的重绘会导致我的窗口/gui 每秒滞后。 我什至试图在另一个线程中更新情节。 但即使在那里我也会滞后。

使用我最新的代码，我的大部分工作都能正常工作。 线程有助于防止我的 GUI/窗口在 Canvas 更新时冻结。

我想念的最后一件事是使它成为线程安全的。

这是我得到的消息：

RuntimeError: main thread is not in main loop

这是我最新的线程工作代码：

from tkinter import *
import random
from random import randint 
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import time
import threading
from datetime import datetime

continuePlotting = False

def change_state():
    global continuePlotting
    if continuePlotting == True:
        continuePlotting = False
    else:
        continuePlotting = True    

def data_points():
    yList = []
    for x in range (0, 20):
        yList.append(random.randint(0, 100))

    return yList

def app():
    # initialise a window and creating the GUI
    root = Tk()
    root.config(background='white')
    root.geometry("1000x700")

    lab = Label(root, text="Live Plotting", bg = 'white').pack()

    fig = Figure()

    ax = fig.add_subplot(111)
    ax.set_ylim(0,100)
    ax.set_xlim(1,30)
    ax.grid()

    graph = FigureCanvasTkAgg(fig, master=root)
    graph.get_tk_widget().pack(side="top",fill='both',expand=True)

    # Updated the Canvas 
    def plotter():
        while continuePlotting:
            ax.cla()
            ax.grid()
            ax.set_ylim(0,100)
            ax.set_xlim(1,20)

            dpts = data_points()
            ax.plot(range(20), dpts, marker='o', color='orange')
            graph.draw()
            time.sleep(1)

    def gui_handler():
        change_state()
        threading.Thread(target=plotter).start()

    b = Button(root, text="Start/Stop", command=gui_handler, bg="red", fg="white")
    b.pack()

    root.mainloop()

if __name__ == '__main__':
    app()

这里没有线程的想法：

from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure
import tkinter as tk
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
import sqlite3
from datetime import datetime
from random import randint

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

        root.update_idletasks()

        f = Figure(figsize=(5,5), dpi=100)        
        x=1
        ax = f.add_subplot(111)        
        line = ax.plot(x, np.sin(x))        

        def animate(i):
            # Open Database
            conn = sqlite3.connect('Sensor_Data.db')
            c = conn.cursor()
            # Create some fake Sensor Data    
            NowIs = datetime.now()
            Temperature = randint(0, 100)
            Humidity = randint(0, 100)
            # Add Data to the Database
            c = conn.cursor()
            # Insert a row of data
            c.execute("insert into Sensor_Stream_1 (Date, Temperature, Humidity) values (?, ?, ?)",
                        (NowIs, Temperature, Humidity))
            # Save (commit) the changes
            conn.commit()
            # Select Data from the Database
            c.execute("SELECT Temperature FROM Sensor_Stream_1 LIMIT 10 OFFSET (SELECT COUNT(*) FROM Sensor_Stream_1)-10") 
            # Gives a list of all temperature values 
            x = 1
            Temperatures = []

            for record in c.fetchall():    
                Temperatures.append(str(x)+','+str(record[0]))
                x+=1
            # Setting up the Plot with X and Y Values
            xList = []
            yList = []

            for eachLine in Temperatures:
                if len(eachLine) > 1:
                    x, y = eachLine.split(',')
                    xList.append(int(x))
                    yList.append(int(y))

            ax.clear()

            ax.plot(xList, yList) 

            ax.set_ylim(0,100)
            ax.set_xlim(1,10)
            ax.grid(b=None, which='major', axis='both', **kwargs)


        label = tk.Label(root,text="Temperature / Humidity").pack(side="top", fill="both", expand=True)

        canvas = FigureCanvasTkAgg(f, master=root)
        canvas.get_tk_widget().pack(side="left", fill="both", expand=True)

        root.ani = animation.FuncAnimation(f, animate, interval=1000)            

if __name__ == "__main__":
    root = tk.Tk()
    MainApplication(root).pack(side="top", fill="both", expand=True)
    root.mainloop()

这是我的数据库架构：

CREATE TABLE `Sensor_Stream_1` (
    `Date`  TEXT,
    `Temperature`   INTEGER,
    `Humidity`  INTEGER
);

Answer 1

您的 GUI 进程不得在任何线程中运行。 只有数据采集必须被线程化。

需要时，将获取的数据传送到 gui 进程（或从可用的新数据通知的 gui 进程）。 我可能需要使用互斥锁在获取线程和 gui 之间共享数据资源（复制时）

主循环看起来像：

running = True
while running:
    root.update()
    if data_available:
        copydata_to_gui()
root.quit()

Answer 2

我在tkinter 上遇到了同样的问题，使用pypubsub事件是我的解决方案。 正如上面的评论所建议的，您必须在另一个线程中运行计算，然后将其发送到 gui 线程。

import time
import tkinter as tk
import threading
from pubsub import pub

lock = threading.Lock()


class MainApplication(tk.Frame):
    def __init__(self, parent, *args, **kwargs):
        tk.Frame.__init__(self, parent, *args, **kwargs)
        self.parent = parent
        self.label = tk.Label(root, text="Temperature / Humidity")
        self.label.pack(side="top", fill="both", expand=True)

    def listener(self, plot_data):
        with lock:
            """do your plot drawing things here"""
            self.label.configure(text=plot_data)


class WorkerThread(threading.Thread):
    def __init__(self):
        super(WorkerThread, self).__init__()
        self.daemon = True  # do not keep thread after app exit
        self._stop = False

    def run(self):
        """calculate your plot data here"""    
        for i in range(100):
            if self._stop:
                break
            time.sleep(1)
            pub.sendMessage('listener', text=str(i))


if __name__ == "__main__":
    root = tk.Tk()
    root.wm_geometry("320x240+100+100")

    main = MainApplication(root)
    main.pack(side="top", fill="both", expand=True)

    pub.subscribe(main.listener, 'listener')

    wt = WorkerThread()
    wt.start()

    root.mainloop()

Answer 3

该函数每秒调用一次，在正常刷新之外。

def start(self,parent):
    self.close=False
    self.Refresh(parent)

def Refresh(self,parent):
    '''your code'''
    if(self.close == False):
        frame.after( UpdateDelay*1000, self.Refresh, parent)

函数是单独调用的，里面发生的一切都不会阻塞接口的正常运行。