Question

我写了一段代码，其中有一个带有画布的简单GUI。在此画布上，我绘制了一个Matplot。 Matplot每秒更新一次SQ Lite数据库中的数据，我在其中填充了一些虚假的Sensor信息（仅用于当前测试）。

我的问题是重新绘制画布会导致我的窗口/ GUI每秒滞后。我什至试图在另一个线程中更新情节。但是即使到那里我也有滞后。

使用最新的代码，我可以完成大部分工作。线程有助于防止Canvas更新时我的GUI /窗口冻结。

我最想念的就是使它成为线程安全。

这是我收到的消息：

RuntimeError: main thread is not in main loop

这是我最新的带有线程的工作代码：

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()

这里没有主意：

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。只有数据采集必须是线程化的。

在需要时，将获取的数据传输到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采集线程和gui之间（在复制时）共享数据资源

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。如上面的注释所示，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

此函数每秒调用一次，它不在常规刷新中。

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)

该函数被单独调用，其内部发生的所有事件均不会阻止接口的正常运行。

如何使Tkinter GUI线程安全？

3 个答案: