Python Forum

I have written a loop that changes a Label. However, I don't know how to wait until the changed label is displayed to start my time delay. If I change the Label then immediately time.sleep(5), the label never gets changed. If I remove the sleep and go though the loop once, the label does get changed but obviously only 1 time. How can I accomplish this? TIA.

See [Tkinter] How to deal with code that blocks the mainloop, freezing the gui

Thanks for that link. I now see what to do but not how to do it. I am struggling trying to figure out what to use for 'after'. The window in question is saved as self.root. If I understand my code should simply be:

print('starting scan')
sensors=self.xml.getSensors()
scan=True
while (scan):
     junk,sensID=self.menu.getNextMenu()
     sens=functions.findID(sensors,sensID)
     print(sensID,sens.temp)
     self.updateLines(sensID,'  *tmp: '+ str(sens.temp))
     self.root.after(0)
     time.sleep(5)

Unfortunately that doesn't work so it is not as simple has I had hoped. The 'updateLines' method is:

def updateLines(self,first,second):
        self.drawLine1(first)
        self.drawLine2(second)

def drawLine1(self,str):
        self.line1=CL.CustomFont_Label(self.root,text=self.pad(str),font_path=se
lf.fontPath,size=36).grid(row=0,column=0,columnspan=5)

def drawLine2(self,str):
        self.line2=CL.CustomFont_Label(self.root,text=self.pad(str),font_path=se
lf.fontPath,size=36).grid(row=1,column=0,columnspan=5)

CustomFont_Label is from this recipe.

It will be something more like this

    def scanning(self):
        junk,sensID=self.menu.getNextMenu()
        sens=functions.findID(self.sensors,sensID)
        print(sensID,sens.temp)
        self.updateLines(sensID,f'  *tmp: {sens.temp}')
        if self.scan:
            self.root.after(5000, self.scanning)

after uses a separate thread to call the passed in callable once the duration of milliseconds is up, the GUI will continue to function as normal.

---

Example

import tkinter as tk
import datetime


class MainFrame(tk.Frame):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.label = tk.Label(self)
        self.label.pack()
        self.pack()
        self.every5sec()

    def every5sec(self):
        self.label['text'] = datetime.datetime.now()
        self.after(5000, self.every5sec)


if __name__ == '__main__':
    app = tk.Tk()
    main_frame = MainFrame()
    app.mainloop()

Thanks. I think I see said the blind man as he picked up a hammer and saw.