refresh automatically text wiget tkinter

**dwblas** · Dec 12 '18, 04:05 PM

Most likely the while True is hogging the processor and not letting anything else happen. Instead of a while True, call another function repeatedly, using after() to update the Text and then call itself again. The small amount of time after() waits before executing gives the processor/Tkinter time to do things like update widgets. The same for any other while True loops. Sorry, but there is too much code for me to trudge through (How come you have this problem at this stage. Has this code not been tested at all?). Will try to come up with a simple example later today, but no promises.

Edit: this is code in my toolbox. Note how the countdown timer creates the Label and then updates it through a second function (the simple progressbar has nothing to do with your question). I would also strongly suggest that you learn classes before Tkinter as it solves some problems, like accessing variables in a called function that were created somewhere else.

Code:

class ProgressBar():
    def __init__(self, root):
        self.root=root
        self.root.geometry("75x50+900+100")
        tk.Button(self.root, text="Quit", bg="red", command=self.root.destroy).pack()
        self.ctr=25
        self.start_progress_bar()
        self.start_countdown()

    def start_progress_bar(self):
        """ create a simple progress bar widget on a canvas
        """
        self.top=tk.Toplevel(self.root, takefocus=True)
        self.top.title("Progress Bar")
        self.top.geometry("+700+200")
        self.canvas = tk.Canvas(self.top, width=261, height=60, background='lightgray')
        self.canvas.pack()

        self.rc1 = self.canvas.create_rectangle(24, 20, 32, 50, outline='white', \
                                      fill='blue')
        self.start_x=20
        self.end_x=235
        self.this_x=self.start_x
        self.one_25th = (self.end_x-self.start_x)/25.0
        rc2 = self.canvas.create_rectangle(self.start_x, 20, self.end_x, 50,
                                       outline='blue', fill='lightblue')
        self.rc1 = self.canvas.create_rectangle(self.start_x, 20, self.start_x+7, 50,
                                       outline='white', fill='blue')

        self.update_scale()

    def start_countdown(self):
        """ a separate process in a separate GUI
        """
        top2=tk.Toplevel(self.root, bg="lightyellow")
        top2.geometry("50x25")
        self.label_ctr = tk.IntVar()
        self.label_ctr.set(self.ctr)
        tk.Label(top2, textvariable=self.label_ctr, width=10,
                 font=("Verdans", 15)).pack()
        if self.ctr > 0:
            self.update()
        else:
            self.top2.destroy()

    def update(self):
        if self.ctr > 0:
            self.label_ctr.set(self.ctr)
            self.ctr -= 1
            self.root.after(750, self.update)
        else:
            ## sleep for one second to allow any remaining after() to execute
            ## can also use self.root.after_cancel(id)
            self.root.after(1000, self.root.destroy)

    def update_scale(self):
        self.canvas.move(self.rc1, self.one_25th, 0)
        self.canvas.update()
        self.this_x += self.one_25th
        ## reverse direction at either end
        if (self.this_x >= self.end_x-12) or self.this_x <= self.start_x+7:
            self.one_25th *= -1

        ## only call after() while the countdown is running (self.ctr > 0)
        ## to avoid a dangling after() when the program terminates
        if self.ctr > 0:
            self.canvas.after(200, self.update_scale)

root = tk.Tk()

PB=ProgressBar(root)
root.mainloop()

refresh automatically text wiget tkinter

refresh automatically text wiget tkinter

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