Cannot refresh custom tkinter frame in real time

Question

I'm trying to continuously refresh a CTkinter frame, but the code keeps getting stuck in the TS_Button_Update() function and the main window doesn't ever open (print(countdown) repeatedly prints, however). I also eventually want the code to also update other characteristics of the GUI such as button colors based on variables - is there any way I can change the code such that it refreshes automatically in real time?

Here is a snippet of the code (the complete program is too long to paste here):

class HomeScreen(customtkinter.CTkFrame):
    def TS_Button_Update(self,TS_progress_Button,temperature):
        countdown = ser_ard1.readline().decode('ascii')
        countdown = countdown.replace('\n','')
        print(countdown)
        temperature.set(countdown)
        TS_progress_Button.configure(text = countdown)
        TS_progress_Button.after(2000,self.TS_Button_Update(TS_progress_Button,temperature))
    
    def __init__(self, master, **kwargs):
        super().__init__(master, **kwargs)
        global TS_progress_Button, temperature
        width, height = self.winfo_screenwidth(), self.winfo_screenheight()
        rrw = width/1920
        rrh= height/1080
        countdown = ser_ard1.readline().decode('ascii')
        countdown = countdown.replace('\n','')
        temperature = StringVar()
        temperature.set(countdown)
        print(countdown)
        
        TS_progress_Button=customtkinter.CTkLabel(self, fg_color=main_fg, bg_color=main_fg, text_color = 'white', width=rrw*225, height=rrh*20
                                                  , textvariable=temperature)
        TS_progress_Button.place(x=rrw*750,y=rrh*1000)
        self.TS_Button_Update(TS_progress_Button,temperature)

I've also tried other variations such as self.update() after calling the TS_Button_Update() for the first time (and removed the built in loop), as well as having the function place a new label at every iteration, and no luck. Can anyone help me figure out what I'm doing wrong please?

score 1 · Accepted Answer · answered Apr 16 '23 at 08:32

When calling TS_progress_Button.after(2000,self.TS_Button_Update(TS_progress_Button,temperature)), you are not actualy passing a refenrence to TS_Button_Update to be executed later, but calling it in place, what will cause the function to be stuck in a loop.

Replace this line with TS_progress_Button.after(2000, self.TS_Button_Update, TS_progress_Button, temperature).

This will schedule the function to be called after a delay of 2000 milliseconds, passing TS_progress_Button and temperature as arguments.

Regarding other gui components

The same approche can be used:

def update_button_color():
    if some_condition:
        TS_progress_Button.configure(bg='red')
    else:
        TS_progress_Button.configure(bg='green')
    TS_progress_Button.after(1000, update_button_color) # The function will be called every second, since it calls itself

# Call the function once to start the periodic updates
update_button_color()

Cannot refresh custom tkinter frame in real time

1 Answers1