refreshing data inside tkinter loop

user_15277820 0
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Situation: I have a tkinter GUI that displays weather data collected from an API. I have a 'get_weather' function which requests data from an API. The response is piped into a 'formatting' function then back to the 'get_weather' function. A formatted string is then displayed as the text of a tkinter Label. The program is intended to run at start up (cronjob) and keep running continuously. It all works great except...

Problem: I can't get the 'get_weather' function to auto refresh. I want the 'get_weather' function to run every 30 minutes to update the data from the API to the GUI.

I have tried: an infinite While loop; which prevents the Tk loop from starting. putting a time.sleep(60) in the code; stops the GUI from launching for a minute. and the after method (see bellow for usage). it didn't seem to do anything unless I made the time parameter a huge number. Then it delayed the GUI launch.

On a side note: I did not make my own class. That's the plan for the next iteration. I'm just not confident making classes. I wanted to get the other problems out of the way before I did that. Also I have all of the functions defined above the start of the Tk loop. They are called within the loop. That just made sense to me but if anyone has a reason why they should be in the loop I want to hear it. I have learned threading but I don't think that's the solution here.

Code looks like: (the program is 300 lines and has other functions. I'm just gonna summarize the problem code)

from Tkinter import Tk*
import [a few other modules]

def change_location(city):
    # passes a 'city' value from an Entry widget
    # sends request to a geo location api for gps coordinates.
    # saves location coordinates to a local config file.
    getweather()

def formatting(json):
    # takes json from api and formats it to a string
    return string

def get_weather():
    # opens a local config file with gps coordinates.
    # Note: the weather api I'm using requires gps coordinates
    # uses gps coordinates in weather api request
    weather['text'] = formatting(response.json())

# start of tkinter loop
root = Tk()
weather = Label(root)
# manual refresh button that works
refresh = Button(root, text="Refresh", command=get_weather)
new_city = Entry(root)

weather.grid(row=0, column=0)
refresh.grid(row=0, column=1)
new_city.grid(row2, column=1)

# after method like his only seems to delay GUI launch only calls 'get_weather' once. 
# I also tried weather.after(10000, get_weather())
root.after(10000, get_weather)
root.mainloop()

I can post the full code I just don't think anyone wants to read through 300 lines for what should be a simple solution.

edit: corrected button naming typo + added 'change_location' function to summery

nested-loops tkinter python loops
2 Answers

Put root.after(1800000, get_weather) inside of get_weather() also, so:

def get_weather():
    root.after(1800000, get_weather) # 30 mins is 1800000 ms

So now once the function is called initially, it will get called every 30 mins.

Though note, button is probably mistyped, you forgot to put it inside Button(). Anyway, if you press the button, then this after() will get called twice, hence speeding up the process. So it is recommended to use flags to make sure that the button is pressed just once and then disable the button. Or find another alternative. I would recommend to not use any buttons at all.

user_133820000

I found a work around. Its not a fail proof solution but it works pretty well. I abstracted the after method to another function 'refresher'. 'refresher' calls 'get_weather' but the after method loops 'refresher' instead of 'get_weather'. 'refresher' is called in the Tk loop.

Using the 'change_location' function still compounds the timer (by calling 'get_weather'). Because the after method is attached to a different function it only compounds the timer for one cycle. Its unlikely the timer would be compounded enough to slow down the program and its corrected in the next cycle either way.

def refresher():
    get_weather()
    root.after(1800000, refresher)
user_152778200
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