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Question

I have a problem with the following python script. Later, it will catch the data from a barcode scanner and display the text as a label. But whenever the text should be changed from the label (highlighted line), the program crashes. I am an absolute beginner Python and can not explain that. I comment out the line, the program works.

from Tkinter import *
import pyHook

class Application(Frame):
    def __init__(self):
        Frame.__init__(self)
        self.master.title("Sc4nn0r")
        self.variable = "Start Variable"

        self.master.geometry("363x200")
        self.master.resizable(0,0)

        self.master.rowconfigure( 0, weight = 1)
        self.master.columnconfigure( 0, weight = 1 )
        self.grid( sticky = W+E+N+S )

        self.label4String = StringVar()
        self.label4 = Label(self, textvariable=self.label4String)
        self.label4.grid( row = 2, column = 1, columnspan = 2, sticky = W+E+N+S)
        self.label4String.set("Variable1")

        self.string = ''
        hook = pyHook.HookManager()
        hook.KeyDown = self.read
        hook.HookKeyboard()

    def read(self, event):
        print(event.Ascii);
        if event.Ascii != 13:
            self.string = self.string + chr(event.Ascii)
        else:
            self.post(self.string.strip(' \0'))
            self.string = ''
        return True

    def post(self,string):
        self.label4String.set(string) # THIS LINE I Mean ##########
        print(string)


def main():
    Application().mainloop()

if __name__ == '__main__':
    main()

I hope it can someone help me.

Answer 1

I would suggest getting rid of StringVar in its entirety. Instead, use self.label4 = Label(self, text = "Variable1") . Then, whenever you wish to change the label, you can use self.label4.config(text = string) .