CODEWITHSUNDEEP
pythontkinter
Jason Woodruff
Jason Woodruff

Reputation: 87

Tkinter - Getting input without the Entry Widget?

Maybe I have titled my question correctly. To explain:

I have a USB barcode scanner that I have hooked up to a RPI2 and I can scan barcodes that will place the 12 digits into a terminal (example 070038348184) with a click of the barcode scanner trigger button. This verifies to me the barcode scanner and the RPI2 can interact with one another. With that said, I am trying to write a Tkinter/Python script to get input from this scanner without using an entry widget. The nature of this project does not have a keyboard, just a touchscreen. So using a entry and button widget to get the barcode scan stored into a variable is what I would like to avoid. I have did some research, but not able to discern any clear cut solution. Finally, I would like to be able to pull the trigger on the scanner and grab the digits from the terminal and store them into a variable for use in the Tkinter/Python script. Any suggestions would be appreciated.

Upvotes: 3

Views: 2388

Answers (1)

furas
furas

Reputation: 142651

As I understand this scanner works as keyboard - it sends keys presses directly to program - so maybe try to use bind('<Key>', callback) to catch all keypresses. 

import tkinter as tk
from tkinter.messagebox import showinfo

def get_key(event):
    global code

    if event.char in '0123456789':
        code += event.char
        #print('>', code)
        label['text'] = code

    elif event.keysym == 'Return':
        #print('result:', code)
        showinfo('Code', code)

# --- main ---

root = tk.Tk()
root.geometry('100x20')

# global variables
code = ''

label = tk.Label(root, text="?")
label.pack()

root.bind('<Key>', get_key)

root.mainloop()

EDIT: as you asked - the same in class

import tkinter as tk
from tkinter.messagebox import showinfo

class Window(tk.Tk):

    def __init__(self):
        tk.Tk.__init__(self)

        self.geometry('100x20')

        self.code = ''

        self.label = tk.Label(self, text="?")
        self.label.pack()

        self.bind('<Key>', self.get_key)

    def get_key(self, event):

        if event.char in '0123456789':
            self.code += event.char
            #print('>', self.code)
            self.label['text'] = self.code

        elif event.keysym == 'Return':
            #print('result:', self.code)
            showinfo('Code', self.code)

# --- main ---

win = Window()
win.mainloop()

#Window().mainloop()

Upvotes: 2

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